5
0
mirror of https://github.com/cwinfo/matterbridge.git synced 2024-12-25 16:25:40 +00:00

Add MediaConvertWebPToPNG option (telegram). (#741)

* Add MediaConvertWebPToPNG option (telegram).

When enabled matterbridge will convert .webp files to .png files
before uploading them to the mediaserver of the other bridges.

Fixes #398
This commit is contained in:
Wim 2019-02-27 00:41:50 +01:00 committed by GitHub
parent d44d2a5f00
commit 26a7e35f27
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
28 changed files with 4317 additions and 0 deletions

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@ -48,6 +48,8 @@ after_script:
- ./cc-test-reporter after-build --exit-code ${TRAVIS_TEST_RESULT}
deploy:
on:
all_branches: true
provider: bintray
on:
all_branches: true

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@ -93,6 +93,7 @@ type Protocol struct {
MediaDownloadSize int // all protocols
MediaServerDownload string
MediaServerUpload string
MediaConvertWebPToPNG bool // telegram
MessageDelay int // IRC, time in millisecond to wait between messages
MessageFormat string // telegram
MessageLength int // IRC, max length of a message allowed

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@ -3,6 +3,7 @@ package helper
import (
"bytes"
"fmt"
"image/png"
"io"
"net/http"
"regexp"
@ -10,6 +11,8 @@ import (
"time"
"unicode/utf8"
"golang.org/x/image/webp"
"github.com/42wim/matterbridge/bridge/config"
"github.com/sirupsen/logrus"
"gitlab.com/golang-commonmark/markdown"
@ -177,3 +180,19 @@ func ParseMarkdown(input string) string {
md := markdown.New(markdown.XHTMLOutput(true), markdown.Breaks(true))
return (md.RenderToString([]byte(input)))
}
// ConvertWebPToPNG convert input data (which should be WebP format to PNG format)
func ConvertWebPToPNG(data *[]byte) error {
r := bytes.NewReader(*data)
m, err := webp.Decode(r)
if err != nil {
return err
}
var output []byte
w := bytes.NewBuffer(output)
if err := png.Encode(w, m); err != nil {
return err
}
*data = w.Bytes()
return nil
}

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@ -1,6 +1,8 @@
package helper
import (
"io/ioutil"
"os"
"testing"
"github.com/stretchr/testify/assert"
@ -103,3 +105,22 @@ func TestGetSubLines(t *testing.T) {
assert.Equalf(t, testcase.nonSplitOutput, nonSplitLines, "'%s' testcase should give expected lines without splitting.", testname)
}
}
func TestConvertWebPToPNG(t *testing.T) {
if os.Getenv("LOCAL_TEST") == "" {
t.Skip()
}
input, err := ioutil.ReadFile("test.webp")
if err != nil {
t.Fail()
}
d := &input
err = ConvertWebPToPNG(d)
if err != nil {
t.Fail()
}
err = ioutil.WriteFile("test.png", *d, 0644)
if err != nil {
t.Fail()
}
}

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@ -245,6 +245,15 @@ func (b *Btelegram) handleDownload(rmsg *config.Message, message *tgbotapi.Messa
if err != nil {
return err
}
if strings.HasSuffix(name, ".webp") && b.GetBool("MediaConvertWebPToPNG") {
b.Log.Debugf("WebP to PNG conversion enabled, converting %s", name)
err := helper.ConvertWebPToPNG(data)
if err != nil {
b.Log.Errorf("conversion failed: %s", err)
} else {
name = strings.Replace(name, ".webp", ".png", 1)
}
}
helper.HandleDownloadData(b.Log, rmsg, name, message.Caption, "", data, b.General)
return nil
}

1
go.mod
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@ -66,6 +66,7 @@ require (
go.uber.org/atomic v1.3.2 // indirect
go.uber.org/multierr v1.1.0 // indirect
go.uber.org/zap v1.9.1 // indirect
golang.org/x/image v0.0.0-20190220214146-31aff87c08e9
gopkg.in/fsnotify.v1 v1.4.7 // indirect
gopkg.in/natefinch/lumberjack.v2 v2.0.0 // indirect
gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 // indirect

2
go.sum
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@ -205,6 +205,8 @@ golang.org/x/crypto v0.0.0-20190130090550-b01c7a725664 h1:YbZJ76lQ1BqNhVe7dKTSB6
golang.org/x/crypto v0.0.0-20190130090550-b01c7a725664/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
golang.org/x/crypto v0.0.0-20190131182504-b8fe1690c613 h1:MQ/ZZiDsUapFFiMS+vzwXkCTeEKaum+Do5rINYJDmxc=
golang.org/x/crypto v0.0.0-20190131182504-b8fe1690c613/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
golang.org/x/image v0.0.0-20190220214146-31aff87c08e9 h1:+vH8qNweCrORN49012OX3h0oWEXO3p+rRnpAGQinddk=
golang.org/x/image v0.0.0-20190220214146-31aff87c08e9/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
golang.org/x/net v0.0.0-20190110200230-915654e7eabc h1:Yx9JGxI1SBhVLFjpAkWMaO1TF+xyqtHLjZpvQboJGiM=
golang.org/x/net v0.0.0-20190110200230-915654e7eabc/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=

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@ -913,6 +913,11 @@ QuoteDisable=false
#OPTIONAL (default "{MESSAGE} (re @{QUOTENICK}: {QUOTEMESSAGE})")
QuoteFormat="{MESSAGE} (re @{QUOTENICK}: {QUOTEMESSAGE})"
#Convert WebP images to PNG before upload.
#https://github.com/42wim/matterbridge/issues/398
#OPTIONAL (default false)
MediaConvertWebPToPNG=false
#Disable sending of edits to other bridges
#OPTIONAL (default false)
EditDisable=false

3
vendor/golang.org/x/image/AUTHORS generated vendored Normal file
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@ -0,0 +1,3 @@
# This source code refers to The Go Authors for copyright purposes.
# The master list of authors is in the main Go distribution,
# visible at http://tip.golang.org/AUTHORS.

3
vendor/golang.org/x/image/CONTRIBUTORS generated vendored Normal file
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@ -0,0 +1,3 @@
# This source code was written by the Go contributors.
# The master list of contributors is in the main Go distribution,
# visible at http://tip.golang.org/CONTRIBUTORS.

27
vendor/golang.org/x/image/LICENSE generated vendored Normal file
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@ -0,0 +1,27 @@
Copyright (c) 2009 The Go Authors. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
* Neither the name of Google Inc. nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

22
vendor/golang.org/x/image/PATENTS generated vendored Normal file
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@ -0,0 +1,22 @@
Additional IP Rights Grant (Patents)
"This implementation" means the copyrightable works distributed by
Google as part of the Go project.
Google hereby grants to You a perpetual, worldwide, non-exclusive,
no-charge, royalty-free, irrevocable (except as stated in this section)
patent license to make, have made, use, offer to sell, sell, import,
transfer and otherwise run, modify and propagate the contents of this
implementation of Go, where such license applies only to those patent
claims, both currently owned or controlled by Google and acquired in
the future, licensable by Google that are necessarily infringed by this
implementation of Go. This grant does not include claims that would be
infringed only as a consequence of further modification of this
implementation. If you or your agent or exclusive licensee institute or
order or agree to the institution of patent litigation against any
entity (including a cross-claim or counterclaim in a lawsuit) alleging
that this implementation of Go or any code incorporated within this
implementation of Go constitutes direct or contributory patent
infringement, or inducement of patent infringement, then any patent
rights granted to you under this License for this implementation of Go
shall terminate as of the date such litigation is filed.

193
vendor/golang.org/x/image/riff/riff.go generated vendored Normal file
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@ -0,0 +1,193 @@
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package riff implements the Resource Interchange File Format, used by media
// formats such as AVI, WAVE and WEBP.
//
// A RIFF stream contains a sequence of chunks. Each chunk consists of an 8-byte
// header (containing a 4-byte chunk type and a 4-byte chunk length), the chunk
// data (presented as an io.Reader), and some padding bytes.
//
// A detailed description of the format is at
// http://www.tactilemedia.com/info/MCI_Control_Info.html
package riff // import "golang.org/x/image/riff"
import (
"errors"
"io"
"io/ioutil"
"math"
)
var (
errMissingPaddingByte = errors.New("riff: missing padding byte")
errMissingRIFFChunkHeader = errors.New("riff: missing RIFF chunk header")
errListSubchunkTooLong = errors.New("riff: list subchunk too long")
errShortChunkData = errors.New("riff: short chunk data")
errShortChunkHeader = errors.New("riff: short chunk header")
errStaleReader = errors.New("riff: stale reader")
)
// u32 decodes the first four bytes of b as a little-endian integer.
func u32(b []byte) uint32 {
return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
}
const chunkHeaderSize = 8
// FourCC is a four character code.
type FourCC [4]byte
// LIST is the "LIST" FourCC.
var LIST = FourCC{'L', 'I', 'S', 'T'}
// NewReader returns the RIFF stream's form type, such as "AVI " or "WAVE", and
// its chunks as a *Reader.
func NewReader(r io.Reader) (formType FourCC, data *Reader, err error) {
var buf [chunkHeaderSize]byte
if _, err := io.ReadFull(r, buf[:]); err != nil {
if err == io.EOF || err == io.ErrUnexpectedEOF {
err = errMissingRIFFChunkHeader
}
return FourCC{}, nil, err
}
if buf[0] != 'R' || buf[1] != 'I' || buf[2] != 'F' || buf[3] != 'F' {
return FourCC{}, nil, errMissingRIFFChunkHeader
}
return NewListReader(u32(buf[4:]), r)
}
// NewListReader returns a LIST chunk's list type, such as "movi" or "wavl",
// and its chunks as a *Reader.
func NewListReader(chunkLen uint32, chunkData io.Reader) (listType FourCC, data *Reader, err error) {
if chunkLen < 4 {
return FourCC{}, nil, errShortChunkData
}
z := &Reader{r: chunkData}
if _, err := io.ReadFull(chunkData, z.buf[:4]); err != nil {
if err == io.EOF || err == io.ErrUnexpectedEOF {
err = errShortChunkData
}
return FourCC{}, nil, err
}
z.totalLen = chunkLen - 4
return FourCC{z.buf[0], z.buf[1], z.buf[2], z.buf[3]}, z, nil
}
// Reader reads chunks from an underlying io.Reader.
type Reader struct {
r io.Reader
err error
totalLen uint32
chunkLen uint32
chunkReader *chunkReader
buf [chunkHeaderSize]byte
padded bool
}
// Next returns the next chunk's ID, length and data. It returns io.EOF if there
// are no more chunks. The io.Reader returned becomes stale after the next Next
// call, and should no longer be used.
//
// It is valid to call Next even if all of the previous chunk's data has not
// been read.
func (z *Reader) Next() (chunkID FourCC, chunkLen uint32, chunkData io.Reader, err error) {
if z.err != nil {
return FourCC{}, 0, nil, z.err
}
// Drain the rest of the previous chunk.
if z.chunkLen != 0 {
want := z.chunkLen
var got int64
got, z.err = io.Copy(ioutil.Discard, z.chunkReader)
if z.err == nil && uint32(got) != want {
z.err = errShortChunkData
}
if z.err != nil {
return FourCC{}, 0, nil, z.err
}
}
z.chunkReader = nil
if z.padded {
if z.totalLen == 0 {
z.err = errListSubchunkTooLong
return FourCC{}, 0, nil, z.err
}
z.totalLen--
_, z.err = io.ReadFull(z.r, z.buf[:1])
if z.err != nil {
if z.err == io.EOF {
z.err = errMissingPaddingByte
}
return FourCC{}, 0, nil, z.err
}
}
// We are done if we have no more data.
if z.totalLen == 0 {
z.err = io.EOF
return FourCC{}, 0, nil, z.err
}
// Read the next chunk header.
if z.totalLen < chunkHeaderSize {
z.err = errShortChunkHeader
return FourCC{}, 0, nil, z.err
}
z.totalLen -= chunkHeaderSize
if _, z.err = io.ReadFull(z.r, z.buf[:chunkHeaderSize]); z.err != nil {
if z.err == io.EOF || z.err == io.ErrUnexpectedEOF {
z.err = errShortChunkHeader
}
return FourCC{}, 0, nil, z.err
}
chunkID = FourCC{z.buf[0], z.buf[1], z.buf[2], z.buf[3]}
z.chunkLen = u32(z.buf[4:])
if z.chunkLen > z.totalLen {
z.err = errListSubchunkTooLong
return FourCC{}, 0, nil, z.err
}
z.padded = z.chunkLen&1 == 1
z.chunkReader = &chunkReader{z}
return chunkID, z.chunkLen, z.chunkReader, nil
}
type chunkReader struct {
z *Reader
}
func (c *chunkReader) Read(p []byte) (int, error) {
if c != c.z.chunkReader {
return 0, errStaleReader
}
z := c.z
if z.err != nil {
if z.err == io.EOF {
return 0, errStaleReader
}
return 0, z.err
}
n := int(z.chunkLen)
if n == 0 {
return 0, io.EOF
}
if n < 0 {
// Converting uint32 to int overflowed.
n = math.MaxInt32
}
if n > len(p) {
n = len(p)
}
n, err := z.r.Read(p[:n])
z.totalLen -= uint32(n)
z.chunkLen -= uint32(n)
if err != io.EOF {
z.err = err
}
return n, err
}

403
vendor/golang.org/x/image/vp8/decode.go generated vendored Normal file
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@ -0,0 +1,403 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package vp8 implements a decoder for the VP8 lossy image format.
//
// The VP8 specification is RFC 6386.
package vp8 // import "golang.org/x/image/vp8"
// This file implements the top-level decoding algorithm.
import (
"errors"
"image"
"io"
)
// limitReader wraps an io.Reader to read at most n bytes from it.
type limitReader struct {
r io.Reader
n int
}
// ReadFull reads exactly len(p) bytes into p.
func (r *limitReader) ReadFull(p []byte) error {
if len(p) > r.n {
return io.ErrUnexpectedEOF
}
n, err := io.ReadFull(r.r, p)
r.n -= n
return err
}
// FrameHeader is a frame header, as specified in section 9.1.
type FrameHeader struct {
KeyFrame bool
VersionNumber uint8
ShowFrame bool
FirstPartitionLen uint32
Width int
Height int
XScale uint8
YScale uint8
}
const (
nSegment = 4
nSegmentProb = 3
)
// segmentHeader holds segment-related header information.
type segmentHeader struct {
useSegment bool
updateMap bool
relativeDelta bool
quantizer [nSegment]int8
filterStrength [nSegment]int8
prob [nSegmentProb]uint8
}
const (
nRefLFDelta = 4
nModeLFDelta = 4
)
// filterHeader holds filter-related header information.
type filterHeader struct {
simple bool
level int8
sharpness uint8
useLFDelta bool
refLFDelta [nRefLFDelta]int8
modeLFDelta [nModeLFDelta]int8
perSegmentLevel [nSegment]int8
}
// mb is the per-macroblock decode state. A decoder maintains mbw+1 of these
// as it is decoding macroblocks left-to-right and top-to-bottom: mbw for the
// macroblocks in the row above, and one for the macroblock to the left.
type mb struct {
// pred is the predictor mode for the 4 bottom or right 4x4 luma regions.
pred [4]uint8
// nzMask is a mask of 8 bits: 4 for the bottom or right 4x4 luma regions,
// and 2 + 2 for the bottom or right 4x4 chroma regions. A 1 bit indicates
// that region has non-zero coefficients.
nzMask uint8
// nzY16 is a 0/1 value that is 1 if the macroblock used Y16 prediction and
// had non-zero coefficients.
nzY16 uint8
}
// Decoder decodes VP8 bitstreams into frames. Decoding one frame consists of
// calling Init, DecodeFrameHeader and then DecodeFrame in that order.
// A Decoder can be re-used to decode multiple frames.
type Decoder struct {
// r is the input bitsream.
r limitReader
// scratch is a scratch buffer.
scratch [8]byte
// img is the YCbCr image to decode into.
img *image.YCbCr
// mbw and mbh are the number of 16x16 macroblocks wide and high the image is.
mbw, mbh int
// frameHeader is the frame header. When decoding multiple frames,
// frames that aren't key frames will inherit the Width, Height,
// XScale and YScale of the most recent key frame.
frameHeader FrameHeader
// Other headers.
segmentHeader segmentHeader
filterHeader filterHeader
// The image data is divided into a number of independent partitions.
// There is 1 "first partition" and between 1 and 8 "other partitions"
// for coefficient data.
fp partition
op [8]partition
nOP int
// Quantization factors.
quant [nSegment]quant
// DCT/WHT coefficient decoding probabilities.
tokenProb [nPlane][nBand][nContext][nProb]uint8
useSkipProb bool
skipProb uint8
// Loop filter parameters.
filterParams [nSegment][2]filterParam
perMBFilterParams []filterParam
// The eight fields below relate to the current macroblock being decoded.
//
// Segment-based adjustments.
segment int
// Per-macroblock state for the macroblock immediately left of and those
// macroblocks immediately above the current macroblock.
leftMB mb
upMB []mb
// Bitmasks for which 4x4 regions of coeff contain non-zero coefficients.
nzDCMask, nzACMask uint32
// Predictor modes.
usePredY16 bool // The libwebp C code calls this !is_i4x4_.
predY16 uint8
predC8 uint8
predY4 [4][4]uint8
// The two fields below form a workspace for reconstructing a macroblock.
// Their specific sizes are documented in reconstruct.go.
coeff [1*16*16 + 2*8*8 + 1*4*4]int16
ybr [1 + 16 + 1 + 8][32]uint8
}
// NewDecoder returns a new Decoder.
func NewDecoder() *Decoder {
return &Decoder{}
}
// Init initializes the decoder to read at most n bytes from r.
func (d *Decoder) Init(r io.Reader, n int) {
d.r = limitReader{r, n}
}
// DecodeFrameHeader decodes the frame header.
func (d *Decoder) DecodeFrameHeader() (fh FrameHeader, err error) {
// All frame headers are at least 3 bytes long.
b := d.scratch[:3]
if err = d.r.ReadFull(b); err != nil {
return
}
d.frameHeader.KeyFrame = (b[0] & 1) == 0
d.frameHeader.VersionNumber = (b[0] >> 1) & 7
d.frameHeader.ShowFrame = (b[0]>>4)&1 == 1
d.frameHeader.FirstPartitionLen = uint32(b[0])>>5 | uint32(b[1])<<3 | uint32(b[2])<<11
if !d.frameHeader.KeyFrame {
return d.frameHeader, nil
}
// Frame headers for key frames are an additional 7 bytes long.
b = d.scratch[:7]
if err = d.r.ReadFull(b); err != nil {
return
}
// Check the magic sync code.
if b[0] != 0x9d || b[1] != 0x01 || b[2] != 0x2a {
err = errors.New("vp8: invalid format")
return
}
d.frameHeader.Width = int(b[4]&0x3f)<<8 | int(b[3])
d.frameHeader.Height = int(b[6]&0x3f)<<8 | int(b[5])
d.frameHeader.XScale = b[4] >> 6
d.frameHeader.YScale = b[6] >> 6
d.mbw = (d.frameHeader.Width + 0x0f) >> 4
d.mbh = (d.frameHeader.Height + 0x0f) >> 4
d.segmentHeader = segmentHeader{
prob: [3]uint8{0xff, 0xff, 0xff},
}
d.tokenProb = defaultTokenProb
d.segment = 0
return d.frameHeader, nil
}
// ensureImg ensures that d.img is large enough to hold the decoded frame.
func (d *Decoder) ensureImg() {
if d.img != nil {
p0, p1 := d.img.Rect.Min, d.img.Rect.Max
if p0.X == 0 && p0.Y == 0 && p1.X >= 16*d.mbw && p1.Y >= 16*d.mbh {
return
}
}
m := image.NewYCbCr(image.Rect(0, 0, 16*d.mbw, 16*d.mbh), image.YCbCrSubsampleRatio420)
d.img = m.SubImage(image.Rect(0, 0, d.frameHeader.Width, d.frameHeader.Height)).(*image.YCbCr)
d.perMBFilterParams = make([]filterParam, d.mbw*d.mbh)
d.upMB = make([]mb, d.mbw)
}
// parseSegmentHeader parses the segment header, as specified in section 9.3.
func (d *Decoder) parseSegmentHeader() {
d.segmentHeader.useSegment = d.fp.readBit(uniformProb)
if !d.segmentHeader.useSegment {
d.segmentHeader.updateMap = false
return
}
d.segmentHeader.updateMap = d.fp.readBit(uniformProb)
if d.fp.readBit(uniformProb) {
d.segmentHeader.relativeDelta = !d.fp.readBit(uniformProb)
for i := range d.segmentHeader.quantizer {
d.segmentHeader.quantizer[i] = int8(d.fp.readOptionalInt(uniformProb, 7))
}
for i := range d.segmentHeader.filterStrength {
d.segmentHeader.filterStrength[i] = int8(d.fp.readOptionalInt(uniformProb, 6))
}
}
if !d.segmentHeader.updateMap {
return
}
for i := range d.segmentHeader.prob {
if d.fp.readBit(uniformProb) {
d.segmentHeader.prob[i] = uint8(d.fp.readUint(uniformProb, 8))
} else {
d.segmentHeader.prob[i] = 0xff
}
}
}
// parseFilterHeader parses the filter header, as specified in section 9.4.
func (d *Decoder) parseFilterHeader() {
d.filterHeader.simple = d.fp.readBit(uniformProb)
d.filterHeader.level = int8(d.fp.readUint(uniformProb, 6))
d.filterHeader.sharpness = uint8(d.fp.readUint(uniformProb, 3))
d.filterHeader.useLFDelta = d.fp.readBit(uniformProb)
if d.filterHeader.useLFDelta && d.fp.readBit(uniformProb) {
for i := range d.filterHeader.refLFDelta {
d.filterHeader.refLFDelta[i] = int8(d.fp.readOptionalInt(uniformProb, 6))
}
for i := range d.filterHeader.modeLFDelta {
d.filterHeader.modeLFDelta[i] = int8(d.fp.readOptionalInt(uniformProb, 6))
}
}
if d.filterHeader.level == 0 {
return
}
if d.segmentHeader.useSegment {
for i := range d.filterHeader.perSegmentLevel {
strength := d.segmentHeader.filterStrength[i]
if d.segmentHeader.relativeDelta {
strength += d.filterHeader.level
}
d.filterHeader.perSegmentLevel[i] = strength
}
} else {
d.filterHeader.perSegmentLevel[0] = d.filterHeader.level
}
d.computeFilterParams()
}
// parseOtherPartitions parses the other partitions, as specified in section 9.5.
func (d *Decoder) parseOtherPartitions() error {
const maxNOP = 1 << 3
var partLens [maxNOP]int
d.nOP = 1 << d.fp.readUint(uniformProb, 2)
// The final partition length is implied by the remaining chunk data
// (d.r.n) and the other d.nOP-1 partition lengths. Those d.nOP-1 partition
// lengths are stored as 24-bit uints, i.e. up to 16 MiB per partition.
n := 3 * (d.nOP - 1)
partLens[d.nOP-1] = d.r.n - n
if partLens[d.nOP-1] < 0 {
return io.ErrUnexpectedEOF
}
if n > 0 {
buf := make([]byte, n)
if err := d.r.ReadFull(buf); err != nil {
return err
}
for i := 0; i < d.nOP-1; i++ {
pl := int(buf[3*i+0]) | int(buf[3*i+1])<<8 | int(buf[3*i+2])<<16
if pl > partLens[d.nOP-1] {
return io.ErrUnexpectedEOF
}
partLens[i] = pl
partLens[d.nOP-1] -= pl
}
}
// We check if the final partition length can also fit into a 24-bit uint.
// Strictly speaking, this isn't part of the spec, but it guards against a
// malicious WEBP image that is too large to ReadFull the encoded DCT
// coefficients into memory, whether that's because the actual WEBP file is
// too large, or whether its RIFF metadata lists too large a chunk.
if 1<<24 <= partLens[d.nOP-1] {
return errors.New("vp8: too much data to decode")
}
buf := make([]byte, d.r.n)
if err := d.r.ReadFull(buf); err != nil {
return err
}
for i, pl := range partLens {
if i == d.nOP {
break
}
d.op[i].init(buf[:pl])
buf = buf[pl:]
}
return nil
}
// parseOtherHeaders parses header information other than the frame header.
func (d *Decoder) parseOtherHeaders() error {
// Initialize and parse the first partition.
firstPartition := make([]byte, d.frameHeader.FirstPartitionLen)
if err := d.r.ReadFull(firstPartition); err != nil {
return err
}
d.fp.init(firstPartition)
if d.frameHeader.KeyFrame {
// Read and ignore the color space and pixel clamp values. They are
// specified in section 9.2, but are unimplemented.
d.fp.readBit(uniformProb)
d.fp.readBit(uniformProb)
}
d.parseSegmentHeader()
d.parseFilterHeader()
if err := d.parseOtherPartitions(); err != nil {
return err
}
d.parseQuant()
if !d.frameHeader.KeyFrame {
// Golden and AltRef frames are specified in section 9.7.
// TODO(nigeltao): implement. Note that they are only used for video, not still images.
return errors.New("vp8: Golden / AltRef frames are not implemented")
}
// Read and ignore the refreshLastFrameBuffer bit, specified in section 9.8.
// It applies only to video, and not still images.
d.fp.readBit(uniformProb)
d.parseTokenProb()
d.useSkipProb = d.fp.readBit(uniformProb)
if d.useSkipProb {
d.skipProb = uint8(d.fp.readUint(uniformProb, 8))
}
if d.fp.unexpectedEOF {
return io.ErrUnexpectedEOF
}
return nil
}
// DecodeFrame decodes the frame and returns it as an YCbCr image.
// The image's contents are valid up until the next call to Decoder.Init.
func (d *Decoder) DecodeFrame() (*image.YCbCr, error) {
d.ensureImg()
if err := d.parseOtherHeaders(); err != nil {
return nil, err
}
// Reconstruct the rows.
for mbx := 0; mbx < d.mbw; mbx++ {
d.upMB[mbx] = mb{}
}
for mby := 0; mby < d.mbh; mby++ {
d.leftMB = mb{}
for mbx := 0; mbx < d.mbw; mbx++ {
skip := d.reconstruct(mbx, mby)
fs := d.filterParams[d.segment][btou(!d.usePredY16)]
fs.inner = fs.inner || !skip
d.perMBFilterParams[d.mbw*mby+mbx] = fs
}
}
if d.fp.unexpectedEOF {
return nil, io.ErrUnexpectedEOF
}
for i := 0; i < d.nOP; i++ {
if d.op[i].unexpectedEOF {
return nil, io.ErrUnexpectedEOF
}
}
// Apply the loop filter.
//
// Even if we are using per-segment levels, section 15 says that "loop
// filtering must be skipped entirely if loop_filter_level at either the
// frame header level or macroblock override level is 0".
if d.filterHeader.level != 0 {
if d.filterHeader.simple {
d.simpleFilter()
} else {
d.normalFilter()
}
}
return d.img, nil
}

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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// filter2 modifies a 2-pixel wide or 2-pixel high band along an edge.
func filter2(pix []byte, level, index, iStep, jStep int) {
for n := 16; n > 0; n, index = n-1, index+iStep {
p1 := int(pix[index-2*jStep])
p0 := int(pix[index-1*jStep])
q0 := int(pix[index+0*jStep])
q1 := int(pix[index+1*jStep])
if abs(p0-q0)<<1+abs(p1-q1)>>1 > level {
continue
}
a := 3*(q0-p0) + clamp127(p1-q1)
a1 := clamp15((a + 4) >> 3)
a2 := clamp15((a + 3) >> 3)
pix[index-1*jStep] = clamp255(p0 + a2)
pix[index+0*jStep] = clamp255(q0 - a1)
}
}
// filter246 modifies a 2-, 4- or 6-pixel wide or high band along an edge.
func filter246(pix []byte, n, level, ilevel, hlevel, index, iStep, jStep int, fourNotSix bool) {
for ; n > 0; n, index = n-1, index+iStep {
p3 := int(pix[index-4*jStep])
p2 := int(pix[index-3*jStep])
p1 := int(pix[index-2*jStep])
p0 := int(pix[index-1*jStep])
q0 := int(pix[index+0*jStep])
q1 := int(pix[index+1*jStep])
q2 := int(pix[index+2*jStep])
q3 := int(pix[index+3*jStep])
if abs(p0-q0)<<1+abs(p1-q1)>>1 > level {
continue
}
if abs(p3-p2) > ilevel ||
abs(p2-p1) > ilevel ||
abs(p1-p0) > ilevel ||
abs(q1-q0) > ilevel ||
abs(q2-q1) > ilevel ||
abs(q3-q2) > ilevel {
continue
}
if abs(p1-p0) > hlevel || abs(q1-q0) > hlevel {
// Filter 2 pixels.
a := 3*(q0-p0) + clamp127(p1-q1)
a1 := clamp15((a + 4) >> 3)
a2 := clamp15((a + 3) >> 3)
pix[index-1*jStep] = clamp255(p0 + a2)
pix[index+0*jStep] = clamp255(q0 - a1)
} else if fourNotSix {
// Filter 4 pixels.
a := 3 * (q0 - p0)
a1 := clamp15((a + 4) >> 3)
a2 := clamp15((a + 3) >> 3)
a3 := (a1 + 1) >> 1
pix[index-2*jStep] = clamp255(p1 + a3)
pix[index-1*jStep] = clamp255(p0 + a2)
pix[index+0*jStep] = clamp255(q0 - a1)
pix[index+1*jStep] = clamp255(q1 - a3)
} else {
// Filter 6 pixels.
a := clamp127(3*(q0-p0) + clamp127(p1-q1))
a1 := (27*a + 63) >> 7
a2 := (18*a + 63) >> 7
a3 := (9*a + 63) >> 7
pix[index-3*jStep] = clamp255(p2 + a3)
pix[index-2*jStep] = clamp255(p1 + a2)
pix[index-1*jStep] = clamp255(p0 + a1)
pix[index+0*jStep] = clamp255(q0 - a1)
pix[index+1*jStep] = clamp255(q1 - a2)
pix[index+2*jStep] = clamp255(q2 - a3)
}
}
}
// simpleFilter implements the simple filter, as specified in section 15.2.
func (d *Decoder) simpleFilter() {
for mby := 0; mby < d.mbh; mby++ {
for mbx := 0; mbx < d.mbw; mbx++ {
f := d.perMBFilterParams[d.mbw*mby+mbx]
if f.level == 0 {
continue
}
l := int(f.level)
yIndex := (mby*d.img.YStride + mbx) * 16
if mbx > 0 {
filter2(d.img.Y, l+4, yIndex, d.img.YStride, 1)
}
if f.inner {
filter2(d.img.Y, l, yIndex+0x4, d.img.YStride, 1)
filter2(d.img.Y, l, yIndex+0x8, d.img.YStride, 1)
filter2(d.img.Y, l, yIndex+0xc, d.img.YStride, 1)
}
if mby > 0 {
filter2(d.img.Y, l+4, yIndex, 1, d.img.YStride)
}
if f.inner {
filter2(d.img.Y, l, yIndex+d.img.YStride*0x4, 1, d.img.YStride)
filter2(d.img.Y, l, yIndex+d.img.YStride*0x8, 1, d.img.YStride)
filter2(d.img.Y, l, yIndex+d.img.YStride*0xc, 1, d.img.YStride)
}
}
}
}
// normalFilter implements the normal filter, as specified in section 15.3.
func (d *Decoder) normalFilter() {
for mby := 0; mby < d.mbh; mby++ {
for mbx := 0; mbx < d.mbw; mbx++ {
f := d.perMBFilterParams[d.mbw*mby+mbx]
if f.level == 0 {
continue
}
l, il, hl := int(f.level), int(f.ilevel), int(f.hlevel)
yIndex := (mby*d.img.YStride + mbx) * 16
cIndex := (mby*d.img.CStride + mbx) * 8
if mbx > 0 {
filter246(d.img.Y, 16, l+4, il, hl, yIndex, d.img.YStride, 1, false)
filter246(d.img.Cb, 8, l+4, il, hl, cIndex, d.img.CStride, 1, false)
filter246(d.img.Cr, 8, l+4, il, hl, cIndex, d.img.CStride, 1, false)
}
if f.inner {
filter246(d.img.Y, 16, l, il, hl, yIndex+0x4, d.img.YStride, 1, true)
filter246(d.img.Y, 16, l, il, hl, yIndex+0x8, d.img.YStride, 1, true)
filter246(d.img.Y, 16, l, il, hl, yIndex+0xc, d.img.YStride, 1, true)
filter246(d.img.Cb, 8, l, il, hl, cIndex+0x4, d.img.CStride, 1, true)
filter246(d.img.Cr, 8, l, il, hl, cIndex+0x4, d.img.CStride, 1, true)
}
if mby > 0 {
filter246(d.img.Y, 16, l+4, il, hl, yIndex, 1, d.img.YStride, false)
filter246(d.img.Cb, 8, l+4, il, hl, cIndex, 1, d.img.CStride, false)
filter246(d.img.Cr, 8, l+4, il, hl, cIndex, 1, d.img.CStride, false)
}
if f.inner {
filter246(d.img.Y, 16, l, il, hl, yIndex+d.img.YStride*0x4, 1, d.img.YStride, true)
filter246(d.img.Y, 16, l, il, hl, yIndex+d.img.YStride*0x8, 1, d.img.YStride, true)
filter246(d.img.Y, 16, l, il, hl, yIndex+d.img.YStride*0xc, 1, d.img.YStride, true)
filter246(d.img.Cb, 8, l, il, hl, cIndex+d.img.CStride*0x4, 1, d.img.CStride, true)
filter246(d.img.Cr, 8, l, il, hl, cIndex+d.img.CStride*0x4, 1, d.img.CStride, true)
}
}
}
}
// filterParam holds the loop filter parameters for a macroblock.
type filterParam struct {
// The first three fields are thresholds used by the loop filter to smooth
// over the edges and interior of a macroblock. level is used by both the
// simple and normal filters. The inner level and high edge variance level
// are only used by the normal filter.
level, ilevel, hlevel uint8
// inner is whether the inner loop filter cannot be optimized out as a
// no-op for this particular macroblock.
inner bool
}
// computeFilterParams computes the loop filter parameters, as specified in
// section 15.4.
func (d *Decoder) computeFilterParams() {
for i := range d.filterParams {
baseLevel := d.filterHeader.level
if d.segmentHeader.useSegment {
baseLevel = d.segmentHeader.filterStrength[i]
if d.segmentHeader.relativeDelta {
baseLevel += d.filterHeader.level
}
}
for j := range d.filterParams[i] {
p := &d.filterParams[i][j]
p.inner = j != 0
level := baseLevel
if d.filterHeader.useLFDelta {
// The libwebp C code has a "TODO: only CURRENT is handled for now."
level += d.filterHeader.refLFDelta[0]
if j != 0 {
level += d.filterHeader.modeLFDelta[0]
}
}
if level <= 0 {
p.level = 0
continue
}
if level > 63 {
level = 63
}
ilevel := level
if d.filterHeader.sharpness > 0 {
if d.filterHeader.sharpness > 4 {
ilevel >>= 2
} else {
ilevel >>= 1
}
if x := int8(9 - d.filterHeader.sharpness); ilevel > x {
ilevel = x
}
}
if ilevel < 1 {
ilevel = 1
}
p.ilevel = uint8(ilevel)
p.level = uint8(2*level + ilevel)
if d.frameHeader.KeyFrame {
if level < 15 {
p.hlevel = 0
} else if level < 40 {
p.hlevel = 1
} else {
p.hlevel = 2
}
} else {
if level < 15 {
p.hlevel = 0
} else if level < 20 {
p.hlevel = 1
} else if level < 40 {
p.hlevel = 2
} else {
p.hlevel = 3
}
}
}
}
}
// intSize is either 32 or 64.
const intSize = 32 << (^uint(0) >> 63)
func abs(x int) int {
// m := -1 if x < 0. m := 0 otherwise.
m := x >> (intSize - 1)
// In two's complement representation, the negative number
// of any number (except the smallest one) can be computed
// by flipping all the bits and add 1. This is faster than
// code with a branch.
// See Hacker's Delight, section 2-4.
return (x ^ m) - m
}
func clamp15(x int) int {
if x < -16 {
return -16
}
if x > 15 {
return 15
}
return x
}
func clamp127(x int) int {
if x < -128 {
return -128
}
if x > 127 {
return 127
}
return x
}
func clamp255(x int) uint8 {
if x < 0 {
return 0
}
if x > 255 {
return 255
}
return uint8(x)
}

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vendor/golang.org/x/image/vp8/idct.go generated vendored Normal file
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// This file implements the inverse Discrete Cosine Transform and the inverse
// Walsh Hadamard Transform (WHT), as specified in sections 14.3 and 14.4.
func clip8(i int32) uint8 {
if i < 0 {
return 0
}
if i > 255 {
return 255
}
return uint8(i)
}
func (z *Decoder) inverseDCT4(y, x, coeffBase int) {
const (
c1 = 85627 // 65536 * cos(pi/8) * sqrt(2).
c2 = 35468 // 65536 * sin(pi/8) * sqrt(2).
)
var m [4][4]int32
for i := 0; i < 4; i++ {
a := int32(z.coeff[coeffBase+0]) + int32(z.coeff[coeffBase+8])
b := int32(z.coeff[coeffBase+0]) - int32(z.coeff[coeffBase+8])
c := (int32(z.coeff[coeffBase+4])*c2)>>16 - (int32(z.coeff[coeffBase+12])*c1)>>16
d := (int32(z.coeff[coeffBase+4])*c1)>>16 + (int32(z.coeff[coeffBase+12])*c2)>>16
m[i][0] = a + d
m[i][1] = b + c
m[i][2] = b - c
m[i][3] = a - d
coeffBase++
}
for j := 0; j < 4; j++ {
dc := m[0][j] + 4
a := dc + m[2][j]
b := dc - m[2][j]
c := (m[1][j]*c2)>>16 - (m[3][j]*c1)>>16
d := (m[1][j]*c1)>>16 + (m[3][j]*c2)>>16
z.ybr[y+j][x+0] = clip8(int32(z.ybr[y+j][x+0]) + (a+d)>>3)
z.ybr[y+j][x+1] = clip8(int32(z.ybr[y+j][x+1]) + (b+c)>>3)
z.ybr[y+j][x+2] = clip8(int32(z.ybr[y+j][x+2]) + (b-c)>>3)
z.ybr[y+j][x+3] = clip8(int32(z.ybr[y+j][x+3]) + (a-d)>>3)
}
}
func (z *Decoder) inverseDCT4DCOnly(y, x, coeffBase int) {
dc := (int32(z.coeff[coeffBase+0]) + 4) >> 3
for j := 0; j < 4; j++ {
for i := 0; i < 4; i++ {
z.ybr[y+j][x+i] = clip8(int32(z.ybr[y+j][x+i]) + dc)
}
}
}
func (z *Decoder) inverseDCT8(y, x, coeffBase int) {
z.inverseDCT4(y+0, x+0, coeffBase+0*16)
z.inverseDCT4(y+0, x+4, coeffBase+1*16)
z.inverseDCT4(y+4, x+0, coeffBase+2*16)
z.inverseDCT4(y+4, x+4, coeffBase+3*16)
}
func (z *Decoder) inverseDCT8DCOnly(y, x, coeffBase int) {
z.inverseDCT4DCOnly(y+0, x+0, coeffBase+0*16)
z.inverseDCT4DCOnly(y+0, x+4, coeffBase+1*16)
z.inverseDCT4DCOnly(y+4, x+0, coeffBase+2*16)
z.inverseDCT4DCOnly(y+4, x+4, coeffBase+3*16)
}
func (d *Decoder) inverseWHT16() {
var m [16]int32
for i := 0; i < 4; i++ {
a0 := int32(d.coeff[384+0+i]) + int32(d.coeff[384+12+i])
a1 := int32(d.coeff[384+4+i]) + int32(d.coeff[384+8+i])
a2 := int32(d.coeff[384+4+i]) - int32(d.coeff[384+8+i])
a3 := int32(d.coeff[384+0+i]) - int32(d.coeff[384+12+i])
m[0+i] = a0 + a1
m[8+i] = a0 - a1
m[4+i] = a3 + a2
m[12+i] = a3 - a2
}
out := 0
for i := 0; i < 4; i++ {
dc := m[0+i*4] + 3
a0 := dc + m[3+i*4]
a1 := m[1+i*4] + m[2+i*4]
a2 := m[1+i*4] - m[2+i*4]
a3 := dc - m[3+i*4]
d.coeff[out+0] = int16((a0 + a1) >> 3)
d.coeff[out+16] = int16((a3 + a2) >> 3)
d.coeff[out+32] = int16((a0 - a1) >> 3)
d.coeff[out+48] = int16((a3 - a2) >> 3)
out += 64
}
}

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vendor/golang.org/x/image/vp8/partition.go generated vendored Normal file
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// Each VP8 frame consists of between 2 and 9 bitstream partitions.
// Each partition is byte-aligned and is independently arithmetic-encoded.
//
// This file implements decoding a partition's bitstream, as specified in
// chapter 7. The implementation follows libwebp's approach instead of the
// specification's reference C implementation. For example, we use a look-up
// table instead of a for loop to recalibrate the encoded range.
var (
lutShift = [127]uint8{
7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
}
lutRangeM1 = [127]uint8{
127,
127, 191,
127, 159, 191, 223,
127, 143, 159, 175, 191, 207, 223, 239,
127, 135, 143, 151, 159, 167, 175, 183, 191, 199, 207, 215, 223, 231, 239, 247,
127, 131, 135, 139, 143, 147, 151, 155, 159, 163, 167, 171, 175, 179, 183, 187,
191, 195, 199, 203, 207, 211, 215, 219, 223, 227, 231, 235, 239, 243, 247, 251,
127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 153, 155, 157,
159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 187, 189,
191, 193, 195, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 219, 221,
223, 225, 227, 229, 231, 233, 235, 237, 239, 241, 243, 245, 247, 249, 251, 253,
}
)
// uniformProb represents a 50% probability that the next bit is 0.
const uniformProb = 128
// partition holds arithmetic-coded bits.
type partition struct {
// buf is the input bytes.
buf []byte
// r is how many of buf's bytes have been consumed.
r int
// rangeM1 is range minus 1, where range is in the arithmetic coding sense,
// not the Go language sense.
rangeM1 uint32
// bits and nBits hold those bits shifted out of buf but not yet consumed.
bits uint32
nBits uint8
// unexpectedEOF tells whether we tried to read past buf.
unexpectedEOF bool
}
// init initializes the partition.
func (p *partition) init(buf []byte) {
p.buf = buf
p.r = 0
p.rangeM1 = 254
p.bits = 0
p.nBits = 0
p.unexpectedEOF = false
}
// readBit returns the next bit.
func (p *partition) readBit(prob uint8) bool {
if p.nBits < 8 {
if p.r >= len(p.buf) {
p.unexpectedEOF = true
return false
}
// Expression split for 386 compiler.
x := uint32(p.buf[p.r])
p.bits |= x << (8 - p.nBits)
p.r++
p.nBits += 8
}
split := (p.rangeM1*uint32(prob))>>8 + 1
bit := p.bits >= split<<8
if bit {
p.rangeM1 -= split
p.bits -= split << 8
} else {
p.rangeM1 = split - 1
}
if p.rangeM1 < 127 {
shift := lutShift[p.rangeM1]
p.rangeM1 = uint32(lutRangeM1[p.rangeM1])
p.bits <<= shift
p.nBits -= shift
}
return bit
}
// readUint returns the next n-bit unsigned integer.
func (p *partition) readUint(prob, n uint8) uint32 {
var u uint32
for n > 0 {
n--
if p.readBit(prob) {
u |= 1 << n
}
}
return u
}
// readInt returns the next n-bit signed integer.
func (p *partition) readInt(prob, n uint8) int32 {
u := p.readUint(prob, n)
b := p.readBit(prob)
if b {
return -int32(u)
}
return int32(u)
}
// readOptionalInt returns the next n-bit signed integer in an encoding
// where the likely result is zero.
func (p *partition) readOptionalInt(prob, n uint8) int32 {
if !p.readBit(prob) {
return 0
}
return p.readInt(prob, n)
}

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// This file implements parsing the predictor modes, as specified in chapter
// 11.
func (d *Decoder) parsePredModeY16(mbx int) {
var p uint8
if !d.fp.readBit(156) {
if !d.fp.readBit(163) {
p = predDC
} else {
p = predVE
}
} else if !d.fp.readBit(128) {
p = predHE
} else {
p = predTM
}
for i := 0; i < 4; i++ {
d.upMB[mbx].pred[i] = p
d.leftMB.pred[i] = p
}
d.predY16 = p
}
func (d *Decoder) parsePredModeC8() {
if !d.fp.readBit(142) {
d.predC8 = predDC
} else if !d.fp.readBit(114) {
d.predC8 = predVE
} else if !d.fp.readBit(183) {
d.predC8 = predHE
} else {
d.predC8 = predTM
}
}
func (d *Decoder) parsePredModeY4(mbx int) {
for j := 0; j < 4; j++ {
p := d.leftMB.pred[j]
for i := 0; i < 4; i++ {
prob := &predProb[d.upMB[mbx].pred[i]][p]
if !d.fp.readBit(prob[0]) {
p = predDC
} else if !d.fp.readBit(prob[1]) {
p = predTM
} else if !d.fp.readBit(prob[2]) {
p = predVE
} else if !d.fp.readBit(prob[3]) {
if !d.fp.readBit(prob[4]) {
p = predHE
} else if !d.fp.readBit(prob[5]) {
p = predRD
} else {
p = predVR
}
} else if !d.fp.readBit(prob[6]) {
p = predLD
} else if !d.fp.readBit(prob[7]) {
p = predVL
} else if !d.fp.readBit(prob[8]) {
p = predHD
} else {
p = predHU
}
d.predY4[j][i] = p
d.upMB[mbx].pred[i] = p
}
d.leftMB.pred[j] = p
}
}
// predProb are the probabilities to decode a 4x4 region's predictor mode given
// the predictor modes of the regions above and left of it.
// These values are specified in section 11.5.
var predProb = [nPred][nPred][9]uint8{
{
{231, 120, 48, 89, 115, 113, 120, 152, 112},
{152, 179, 64, 126, 170, 118, 46, 70, 95},
{175, 69, 143, 80, 85, 82, 72, 155, 103},
{56, 58, 10, 171, 218, 189, 17, 13, 152},
{114, 26, 17, 163, 44, 195, 21, 10, 173},
{121, 24, 80, 195, 26, 62, 44, 64, 85},
{144, 71, 10, 38, 171, 213, 144, 34, 26},
{170, 46, 55, 19, 136, 160, 33, 206, 71},
{63, 20, 8, 114, 114, 208, 12, 9, 226},
{81, 40, 11, 96, 182, 84, 29, 16, 36},
},
{
{134, 183, 89, 137, 98, 101, 106, 165, 148},
{72, 187, 100, 130, 157, 111, 32, 75, 80},
{66, 102, 167, 99, 74, 62, 40, 234, 128},
{41, 53, 9, 178, 241, 141, 26, 8, 107},
{74, 43, 26, 146, 73, 166, 49, 23, 157},
{65, 38, 105, 160, 51, 52, 31, 115, 128},
{104, 79, 12, 27, 217, 255, 87, 17, 7},
{87, 68, 71, 44, 114, 51, 15, 186, 23},
{47, 41, 14, 110, 182, 183, 21, 17, 194},
{66, 45, 25, 102, 197, 189, 23, 18, 22},
},
{
{88, 88, 147, 150, 42, 46, 45, 196, 205},
{43, 97, 183, 117, 85, 38, 35, 179, 61},
{39, 53, 200, 87, 26, 21, 43, 232, 171},
{56, 34, 51, 104, 114, 102, 29, 93, 77},
{39, 28, 85, 171, 58, 165, 90, 98, 64},
{34, 22, 116, 206, 23, 34, 43, 166, 73},
{107, 54, 32, 26, 51, 1, 81, 43, 31},
{68, 25, 106, 22, 64, 171, 36, 225, 114},
{34, 19, 21, 102, 132, 188, 16, 76, 124},
{62, 18, 78, 95, 85, 57, 50, 48, 51},
},
{
{193, 101, 35, 159, 215, 111, 89, 46, 111},
{60, 148, 31, 172, 219, 228, 21, 18, 111},
{112, 113, 77, 85, 179, 255, 38, 120, 114},
{40, 42, 1, 196, 245, 209, 10, 25, 109},
{88, 43, 29, 140, 166, 213, 37, 43, 154},
{61, 63, 30, 155, 67, 45, 68, 1, 209},
{100, 80, 8, 43, 154, 1, 51, 26, 71},
{142, 78, 78, 16, 255, 128, 34, 197, 171},
{41, 40, 5, 102, 211, 183, 4, 1, 221},
{51, 50, 17, 168, 209, 192, 23, 25, 82},
},
{
{138, 31, 36, 171, 27, 166, 38, 44, 229},
{67, 87, 58, 169, 82, 115, 26, 59, 179},
{63, 59, 90, 180, 59, 166, 93, 73, 154},
{40, 40, 21, 116, 143, 209, 34, 39, 175},
{47, 15, 16, 183, 34, 223, 49, 45, 183},
{46, 17, 33, 183, 6, 98, 15, 32, 183},
{57, 46, 22, 24, 128, 1, 54, 17, 37},
{65, 32, 73, 115, 28, 128, 23, 128, 205},
{40, 3, 9, 115, 51, 192, 18, 6, 223},
{87, 37, 9, 115, 59, 77, 64, 21, 47},
},
{
{104, 55, 44, 218, 9, 54, 53, 130, 226},
{64, 90, 70, 205, 40, 41, 23, 26, 57},
{54, 57, 112, 184, 5, 41, 38, 166, 213},
{30, 34, 26, 133, 152, 116, 10, 32, 134},
{39, 19, 53, 221, 26, 114, 32, 73, 255},
{31, 9, 65, 234, 2, 15, 1, 118, 73},
{75, 32, 12, 51, 192, 255, 160, 43, 51},
{88, 31, 35, 67, 102, 85, 55, 186, 85},
{56, 21, 23, 111, 59, 205, 45, 37, 192},
{55, 38, 70, 124, 73, 102, 1, 34, 98},
},
{
{125, 98, 42, 88, 104, 85, 117, 175, 82},
{95, 84, 53, 89, 128, 100, 113, 101, 45},
{75, 79, 123, 47, 51, 128, 81, 171, 1},
{57, 17, 5, 71, 102, 57, 53, 41, 49},
{38, 33, 13, 121, 57, 73, 26, 1, 85},
{41, 10, 67, 138, 77, 110, 90, 47, 114},
{115, 21, 2, 10, 102, 255, 166, 23, 6},
{101, 29, 16, 10, 85, 128, 101, 196, 26},
{57, 18, 10, 102, 102, 213, 34, 20, 43},
{117, 20, 15, 36, 163, 128, 68, 1, 26},
},
{
{102, 61, 71, 37, 34, 53, 31, 243, 192},
{69, 60, 71, 38, 73, 119, 28, 222, 37},
{68, 45, 128, 34, 1, 47, 11, 245, 171},
{62, 17, 19, 70, 146, 85, 55, 62, 70},
{37, 43, 37, 154, 100, 163, 85, 160, 1},
{63, 9, 92, 136, 28, 64, 32, 201, 85},
{75, 15, 9, 9, 64, 255, 184, 119, 16},
{86, 6, 28, 5, 64, 255, 25, 248, 1},
{56, 8, 17, 132, 137, 255, 55, 116, 128},
{58, 15, 20, 82, 135, 57, 26, 121, 40},
},
{
{164, 50, 31, 137, 154, 133, 25, 35, 218},
{51, 103, 44, 131, 131, 123, 31, 6, 158},
{86, 40, 64, 135, 148, 224, 45, 183, 128},
{22, 26, 17, 131, 240, 154, 14, 1, 209},
{45, 16, 21, 91, 64, 222, 7, 1, 197},
{56, 21, 39, 155, 60, 138, 23, 102, 213},
{83, 12, 13, 54, 192, 255, 68, 47, 28},
{85, 26, 85, 85, 128, 128, 32, 146, 171},
{18, 11, 7, 63, 144, 171, 4, 4, 246},
{35, 27, 10, 146, 174, 171, 12, 26, 128},
},
{
{190, 80, 35, 99, 180, 80, 126, 54, 45},
{85, 126, 47, 87, 176, 51, 41, 20, 32},
{101, 75, 128, 139, 118, 146, 116, 128, 85},
{56, 41, 15, 176, 236, 85, 37, 9, 62},
{71, 30, 17, 119, 118, 255, 17, 18, 138},
{101, 38, 60, 138, 55, 70, 43, 26, 142},
{146, 36, 19, 30, 171, 255, 97, 27, 20},
{138, 45, 61, 62, 219, 1, 81, 188, 64},
{32, 41, 20, 117, 151, 142, 20, 21, 163},
{112, 19, 12, 61, 195, 128, 48, 4, 24},
},
}

553
vendor/golang.org/x/image/vp8/predfunc.go generated vendored Normal file
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@ -0,0 +1,553 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// This file implements the predicition functions, as specified in chapter 12.
//
// For each macroblock (of 1x16x16 luma and 2x8x8 chroma coefficients), the
// luma values are either predicted as one large 16x16 region or 16 separate
// 4x4 regions. The chroma values are always predicted as one 8x8 region.
//
// For 4x4 regions, the target block's predicted values (Xs) are a function of
// its previously-decoded top and left border values, as well as a number of
// pixels from the top-right:
//
// a b c d e f g h
// p X X X X
// q X X X X
// r X X X X
// s X X X X
//
// The predictor modes are:
// - DC: all Xs = (b + c + d + e + p + q + r + s + 4) / 8.
// - TM: the first X = (b + p - a), the second X = (c + p - a), and so on.
// - VE: each X = the weighted average of its column's top value and that
// value's neighbors, i.e. averages of abc, bcd, cde or def.
// - HE: similar to VE except rows instead of columns, and the final row is
// an average of r, s and s.
// - RD, VR, LD, VL, HD, HU: these diagonal modes ("Right Down", "Vertical
// Right", etc) are more complicated and are described in section 12.3.
// All Xs are clipped to the range [0, 255].
//
// For 8x8 and 16x16 regions, the target block's predicted values are a
// function of the top and left border values without the top-right overhang,
// i.e. without the 8x8 or 16x16 equivalent of f, g and h. Furthermore:
// - There are no diagonal predictor modes, only DC, TM, VE and HE.
// - The DC mode has variants for macroblocks in the top row and/or left
// column, i.e. for macroblocks with mby == 0 || mbx == 0.
// - The VE and HE modes take only the column top or row left values; they do
// not smooth that top/left value with its neighbors.
// nPred is the number of predictor modes, not including the Top/Left versions
// of the DC predictor mode.
const nPred = 10
const (
predDC = iota
predTM
predVE
predHE
predRD
predVR
predLD
predVL
predHD
predHU
predDCTop
predDCLeft
predDCTopLeft
)
func checkTopLeftPred(mbx, mby int, p uint8) uint8 {
if p != predDC {
return p
}
if mbx == 0 {
if mby == 0 {
return predDCTopLeft
}
return predDCLeft
}
if mby == 0 {
return predDCTop
}
return predDC
}
var predFunc4 = [...]func(*Decoder, int, int){
predFunc4DC,
predFunc4TM,
predFunc4VE,
predFunc4HE,
predFunc4RD,
predFunc4VR,
predFunc4LD,
predFunc4VL,
predFunc4HD,
predFunc4HU,
nil,
nil,
nil,
}
var predFunc8 = [...]func(*Decoder, int, int){
predFunc8DC,
predFunc8TM,
predFunc8VE,
predFunc8HE,
nil,
nil,
nil,
nil,
nil,
nil,
predFunc8DCTop,
predFunc8DCLeft,
predFunc8DCTopLeft,
}
var predFunc16 = [...]func(*Decoder, int, int){
predFunc16DC,
predFunc16TM,
predFunc16VE,
predFunc16HE,
nil,
nil,
nil,
nil,
nil,
nil,
predFunc16DCTop,
predFunc16DCLeft,
predFunc16DCTopLeft,
}
func predFunc4DC(z *Decoder, y, x int) {
sum := uint32(4)
for i := 0; i < 4; i++ {
sum += uint32(z.ybr[y-1][x+i])
}
for j := 0; j < 4; j++ {
sum += uint32(z.ybr[y+j][x-1])
}
avg := uint8(sum / 8)
for j := 0; j < 4; j++ {
for i := 0; i < 4; i++ {
z.ybr[y+j][x+i] = avg
}
}
}
func predFunc4TM(z *Decoder, y, x int) {
delta0 := -int32(z.ybr[y-1][x-1])
for j := 0; j < 4; j++ {
delta1 := delta0 + int32(z.ybr[y+j][x-1])
for i := 0; i < 4; i++ {
delta2 := delta1 + int32(z.ybr[y-1][x+i])
z.ybr[y+j][x+i] = uint8(clip(delta2, 0, 255))
}
}
}
func predFunc4VE(z *Decoder, y, x int) {
a := int32(z.ybr[y-1][x-1])
b := int32(z.ybr[y-1][x+0])
c := int32(z.ybr[y-1][x+1])
d := int32(z.ybr[y-1][x+2])
e := int32(z.ybr[y-1][x+3])
f := int32(z.ybr[y-1][x+4])
abc := uint8((a + 2*b + c + 2) / 4)
bcd := uint8((b + 2*c + d + 2) / 4)
cde := uint8((c + 2*d + e + 2) / 4)
def := uint8((d + 2*e + f + 2) / 4)
for j := 0; j < 4; j++ {
z.ybr[y+j][x+0] = abc
z.ybr[y+j][x+1] = bcd
z.ybr[y+j][x+2] = cde
z.ybr[y+j][x+3] = def
}
}
func predFunc4HE(z *Decoder, y, x int) {
s := int32(z.ybr[y+3][x-1])
r := int32(z.ybr[y+2][x-1])
q := int32(z.ybr[y+1][x-1])
p := int32(z.ybr[y+0][x-1])
a := int32(z.ybr[y-1][x-1])
ssr := uint8((s + 2*s + r + 2) / 4)
srq := uint8((s + 2*r + q + 2) / 4)
rqp := uint8((r + 2*q + p + 2) / 4)
apq := uint8((a + 2*p + q + 2) / 4)
for i := 0; i < 4; i++ {
z.ybr[y+0][x+i] = apq
z.ybr[y+1][x+i] = rqp
z.ybr[y+2][x+i] = srq
z.ybr[y+3][x+i] = ssr
}
}
func predFunc4RD(z *Decoder, y, x int) {
s := int32(z.ybr[y+3][x-1])
r := int32(z.ybr[y+2][x-1])
q := int32(z.ybr[y+1][x-1])
p := int32(z.ybr[y+0][x-1])
a := int32(z.ybr[y-1][x-1])
b := int32(z.ybr[y-1][x+0])
c := int32(z.ybr[y-1][x+1])
d := int32(z.ybr[y-1][x+2])
e := int32(z.ybr[y-1][x+3])
srq := uint8((s + 2*r + q + 2) / 4)
rqp := uint8((r + 2*q + p + 2) / 4)
qpa := uint8((q + 2*p + a + 2) / 4)
pab := uint8((p + 2*a + b + 2) / 4)
abc := uint8((a + 2*b + c + 2) / 4)
bcd := uint8((b + 2*c + d + 2) / 4)
cde := uint8((c + 2*d + e + 2) / 4)
z.ybr[y+0][x+0] = pab
z.ybr[y+0][x+1] = abc
z.ybr[y+0][x+2] = bcd
z.ybr[y+0][x+3] = cde
z.ybr[y+1][x+0] = qpa
z.ybr[y+1][x+1] = pab
z.ybr[y+1][x+2] = abc
z.ybr[y+1][x+3] = bcd
z.ybr[y+2][x+0] = rqp
z.ybr[y+2][x+1] = qpa
z.ybr[y+2][x+2] = pab
z.ybr[y+2][x+3] = abc
z.ybr[y+3][x+0] = srq
z.ybr[y+3][x+1] = rqp
z.ybr[y+3][x+2] = qpa
z.ybr[y+3][x+3] = pab
}
func predFunc4VR(z *Decoder, y, x int) {
r := int32(z.ybr[y+2][x-1])
q := int32(z.ybr[y+1][x-1])
p := int32(z.ybr[y+0][x-1])
a := int32(z.ybr[y-1][x-1])
b := int32(z.ybr[y-1][x+0])
c := int32(z.ybr[y-1][x+1])
d := int32(z.ybr[y-1][x+2])
e := int32(z.ybr[y-1][x+3])
ab := uint8((a + b + 1) / 2)
bc := uint8((b + c + 1) / 2)
cd := uint8((c + d + 1) / 2)
de := uint8((d + e + 1) / 2)
rqp := uint8((r + 2*q + p + 2) / 4)
qpa := uint8((q + 2*p + a + 2) / 4)
pab := uint8((p + 2*a + b + 2) / 4)
abc := uint8((a + 2*b + c + 2) / 4)
bcd := uint8((b + 2*c + d + 2) / 4)
cde := uint8((c + 2*d + e + 2) / 4)
z.ybr[y+0][x+0] = ab
z.ybr[y+0][x+1] = bc
z.ybr[y+0][x+2] = cd
z.ybr[y+0][x+3] = de
z.ybr[y+1][x+0] = pab
z.ybr[y+1][x+1] = abc
z.ybr[y+1][x+2] = bcd
z.ybr[y+1][x+3] = cde
z.ybr[y+2][x+0] = qpa
z.ybr[y+2][x+1] = ab
z.ybr[y+2][x+2] = bc
z.ybr[y+2][x+3] = cd
z.ybr[y+3][x+0] = rqp
z.ybr[y+3][x+1] = pab
z.ybr[y+3][x+2] = abc
z.ybr[y+3][x+3] = bcd
}
func predFunc4LD(z *Decoder, y, x int) {
a := int32(z.ybr[y-1][x+0])
b := int32(z.ybr[y-1][x+1])
c := int32(z.ybr[y-1][x+2])
d := int32(z.ybr[y-1][x+3])
e := int32(z.ybr[y-1][x+4])
f := int32(z.ybr[y-1][x+5])
g := int32(z.ybr[y-1][x+6])
h := int32(z.ybr[y-1][x+7])
abc := uint8((a + 2*b + c + 2) / 4)
bcd := uint8((b + 2*c + d + 2) / 4)
cde := uint8((c + 2*d + e + 2) / 4)
def := uint8((d + 2*e + f + 2) / 4)
efg := uint8((e + 2*f + g + 2) / 4)
fgh := uint8((f + 2*g + h + 2) / 4)
ghh := uint8((g + 2*h + h + 2) / 4)
z.ybr[y+0][x+0] = abc
z.ybr[y+0][x+1] = bcd
z.ybr[y+0][x+2] = cde
z.ybr[y+0][x+3] = def
z.ybr[y+1][x+0] = bcd
z.ybr[y+1][x+1] = cde
z.ybr[y+1][x+2] = def
z.ybr[y+1][x+3] = efg
z.ybr[y+2][x+0] = cde
z.ybr[y+2][x+1] = def
z.ybr[y+2][x+2] = efg
z.ybr[y+2][x+3] = fgh
z.ybr[y+3][x+0] = def
z.ybr[y+3][x+1] = efg
z.ybr[y+3][x+2] = fgh
z.ybr[y+3][x+3] = ghh
}
func predFunc4VL(z *Decoder, y, x int) {
a := int32(z.ybr[y-1][x+0])
b := int32(z.ybr[y-1][x+1])
c := int32(z.ybr[y-1][x+2])
d := int32(z.ybr[y-1][x+3])
e := int32(z.ybr[y-1][x+4])
f := int32(z.ybr[y-1][x+5])
g := int32(z.ybr[y-1][x+6])
h := int32(z.ybr[y-1][x+7])
ab := uint8((a + b + 1) / 2)
bc := uint8((b + c + 1) / 2)
cd := uint8((c + d + 1) / 2)
de := uint8((d + e + 1) / 2)
abc := uint8((a + 2*b + c + 2) / 4)
bcd := uint8((b + 2*c + d + 2) / 4)
cde := uint8((c + 2*d + e + 2) / 4)
def := uint8((d + 2*e + f + 2) / 4)
efg := uint8((e + 2*f + g + 2) / 4)
fgh := uint8((f + 2*g + h + 2) / 4)
z.ybr[y+0][x+0] = ab
z.ybr[y+0][x+1] = bc
z.ybr[y+0][x+2] = cd
z.ybr[y+0][x+3] = de
z.ybr[y+1][x+0] = abc
z.ybr[y+1][x+1] = bcd
z.ybr[y+1][x+2] = cde
z.ybr[y+1][x+3] = def
z.ybr[y+2][x+0] = bc
z.ybr[y+2][x+1] = cd
z.ybr[y+2][x+2] = de
z.ybr[y+2][x+3] = efg
z.ybr[y+3][x+0] = bcd
z.ybr[y+3][x+1] = cde
z.ybr[y+3][x+2] = def
z.ybr[y+3][x+3] = fgh
}
func predFunc4HD(z *Decoder, y, x int) {
s := int32(z.ybr[y+3][x-1])
r := int32(z.ybr[y+2][x-1])
q := int32(z.ybr[y+1][x-1])
p := int32(z.ybr[y+0][x-1])
a := int32(z.ybr[y-1][x-1])
b := int32(z.ybr[y-1][x+0])
c := int32(z.ybr[y-1][x+1])
d := int32(z.ybr[y-1][x+2])
sr := uint8((s + r + 1) / 2)
rq := uint8((r + q + 1) / 2)
qp := uint8((q + p + 1) / 2)
pa := uint8((p + a + 1) / 2)
srq := uint8((s + 2*r + q + 2) / 4)
rqp := uint8((r + 2*q + p + 2) / 4)
qpa := uint8((q + 2*p + a + 2) / 4)
pab := uint8((p + 2*a + b + 2) / 4)
abc := uint8((a + 2*b + c + 2) / 4)
bcd := uint8((b + 2*c + d + 2) / 4)
z.ybr[y+0][x+0] = pa
z.ybr[y+0][x+1] = pab
z.ybr[y+0][x+2] = abc
z.ybr[y+0][x+3] = bcd
z.ybr[y+1][x+0] = qp
z.ybr[y+1][x+1] = qpa
z.ybr[y+1][x+2] = pa
z.ybr[y+1][x+3] = pab
z.ybr[y+2][x+0] = rq
z.ybr[y+2][x+1] = rqp
z.ybr[y+2][x+2] = qp
z.ybr[y+2][x+3] = qpa
z.ybr[y+3][x+0] = sr
z.ybr[y+3][x+1] = srq
z.ybr[y+3][x+2] = rq
z.ybr[y+3][x+3] = rqp
}
func predFunc4HU(z *Decoder, y, x int) {
s := int32(z.ybr[y+3][x-1])
r := int32(z.ybr[y+2][x-1])
q := int32(z.ybr[y+1][x-1])
p := int32(z.ybr[y+0][x-1])
pq := uint8((p + q + 1) / 2)
qr := uint8((q + r + 1) / 2)
rs := uint8((r + s + 1) / 2)
pqr := uint8((p + 2*q + r + 2) / 4)
qrs := uint8((q + 2*r + s + 2) / 4)
rss := uint8((r + 2*s + s + 2) / 4)
sss := uint8(s)
z.ybr[y+0][x+0] = pq
z.ybr[y+0][x+1] = pqr
z.ybr[y+0][x+2] = qr
z.ybr[y+0][x+3] = qrs
z.ybr[y+1][x+0] = qr
z.ybr[y+1][x+1] = qrs
z.ybr[y+1][x+2] = rs
z.ybr[y+1][x+3] = rss
z.ybr[y+2][x+0] = rs
z.ybr[y+2][x+1] = rss
z.ybr[y+2][x+2] = sss
z.ybr[y+2][x+3] = sss
z.ybr[y+3][x+0] = sss
z.ybr[y+3][x+1] = sss
z.ybr[y+3][x+2] = sss
z.ybr[y+3][x+3] = sss
}
func predFunc8DC(z *Decoder, y, x int) {
sum := uint32(8)
for i := 0; i < 8; i++ {
sum += uint32(z.ybr[y-1][x+i])
}
for j := 0; j < 8; j++ {
sum += uint32(z.ybr[y+j][x-1])
}
avg := uint8(sum / 16)
for j := 0; j < 8; j++ {
for i := 0; i < 8; i++ {
z.ybr[y+j][x+i] = avg
}
}
}
func predFunc8TM(z *Decoder, y, x int) {
delta0 := -int32(z.ybr[y-1][x-1])
for j := 0; j < 8; j++ {
delta1 := delta0 + int32(z.ybr[y+j][x-1])
for i := 0; i < 8; i++ {
delta2 := delta1 + int32(z.ybr[y-1][x+i])
z.ybr[y+j][x+i] = uint8(clip(delta2, 0, 255))
}
}
}
func predFunc8VE(z *Decoder, y, x int) {
for j := 0; j < 8; j++ {
for i := 0; i < 8; i++ {
z.ybr[y+j][x+i] = z.ybr[y-1][x+i]
}
}
}
func predFunc8HE(z *Decoder, y, x int) {
for j := 0; j < 8; j++ {
for i := 0; i < 8; i++ {
z.ybr[y+j][x+i] = z.ybr[y+j][x-1]
}
}
}
func predFunc8DCTop(z *Decoder, y, x int) {
sum := uint32(4)
for j := 0; j < 8; j++ {
sum += uint32(z.ybr[y+j][x-1])
}
avg := uint8(sum / 8)
for j := 0; j < 8; j++ {
for i := 0; i < 8; i++ {
z.ybr[y+j][x+i] = avg
}
}
}
func predFunc8DCLeft(z *Decoder, y, x int) {
sum := uint32(4)
for i := 0; i < 8; i++ {
sum += uint32(z.ybr[y-1][x+i])
}
avg := uint8(sum / 8)
for j := 0; j < 8; j++ {
for i := 0; i < 8; i++ {
z.ybr[y+j][x+i] = avg
}
}
}
func predFunc8DCTopLeft(z *Decoder, y, x int) {
for j := 0; j < 8; j++ {
for i := 0; i < 8; i++ {
z.ybr[y+j][x+i] = 0x80
}
}
}
func predFunc16DC(z *Decoder, y, x int) {
sum := uint32(16)
for i := 0; i < 16; i++ {
sum += uint32(z.ybr[y-1][x+i])
}
for j := 0; j < 16; j++ {
sum += uint32(z.ybr[y+j][x-1])
}
avg := uint8(sum / 32)
for j := 0; j < 16; j++ {
for i := 0; i < 16; i++ {
z.ybr[y+j][x+i] = avg
}
}
}
func predFunc16TM(z *Decoder, y, x int) {
delta0 := -int32(z.ybr[y-1][x-1])
for j := 0; j < 16; j++ {
delta1 := delta0 + int32(z.ybr[y+j][x-1])
for i := 0; i < 16; i++ {
delta2 := delta1 + int32(z.ybr[y-1][x+i])
z.ybr[y+j][x+i] = uint8(clip(delta2, 0, 255))
}
}
}
func predFunc16VE(z *Decoder, y, x int) {
for j := 0; j < 16; j++ {
for i := 0; i < 16; i++ {
z.ybr[y+j][x+i] = z.ybr[y-1][x+i]
}
}
}
func predFunc16HE(z *Decoder, y, x int) {
for j := 0; j < 16; j++ {
for i := 0; i < 16; i++ {
z.ybr[y+j][x+i] = z.ybr[y+j][x-1]
}
}
}
func predFunc16DCTop(z *Decoder, y, x int) {
sum := uint32(8)
for j := 0; j < 16; j++ {
sum += uint32(z.ybr[y+j][x-1])
}
avg := uint8(sum / 16)
for j := 0; j < 16; j++ {
for i := 0; i < 16; i++ {
z.ybr[y+j][x+i] = avg
}
}
}
func predFunc16DCLeft(z *Decoder, y, x int) {
sum := uint32(8)
for i := 0; i < 16; i++ {
sum += uint32(z.ybr[y-1][x+i])
}
avg := uint8(sum / 16)
for j := 0; j < 16; j++ {
for i := 0; i < 16; i++ {
z.ybr[y+j][x+i] = avg
}
}
}
func predFunc16DCTopLeft(z *Decoder, y, x int) {
for j := 0; j < 16; j++ {
for i := 0; i < 16; i++ {
z.ybr[y+j][x+i] = 0x80
}
}
}

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// This file implements parsing the quantization factors.
// quant are DC/AC quantization factors.
type quant struct {
y1 [2]uint16
y2 [2]uint16
uv [2]uint16
}
// clip clips x to the range [min, max] inclusive.
func clip(x, min, max int32) int32 {
if x < min {
return min
}
if x > max {
return max
}
return x
}
// parseQuant parses the quantization factors, as specified in section 9.6.
func (d *Decoder) parseQuant() {
baseQ0 := d.fp.readUint(uniformProb, 7)
dqy1DC := d.fp.readOptionalInt(uniformProb, 4)
const dqy1AC = 0
dqy2DC := d.fp.readOptionalInt(uniformProb, 4)
dqy2AC := d.fp.readOptionalInt(uniformProb, 4)
dquvDC := d.fp.readOptionalInt(uniformProb, 4)
dquvAC := d.fp.readOptionalInt(uniformProb, 4)
for i := 0; i < nSegment; i++ {
q := int32(baseQ0)
if d.segmentHeader.useSegment {
if d.segmentHeader.relativeDelta {
q += int32(d.segmentHeader.quantizer[i])
} else {
q = int32(d.segmentHeader.quantizer[i])
}
}
d.quant[i].y1[0] = dequantTableDC[clip(q+dqy1DC, 0, 127)]
d.quant[i].y1[1] = dequantTableAC[clip(q+dqy1AC, 0, 127)]
d.quant[i].y2[0] = dequantTableDC[clip(q+dqy2DC, 0, 127)] * 2
d.quant[i].y2[1] = dequantTableAC[clip(q+dqy2AC, 0, 127)] * 155 / 100
if d.quant[i].y2[1] < 8 {
d.quant[i].y2[1] = 8
}
// The 117 is not a typo. The dequant_init function in the spec's Reference
// Decoder Source Code (http://tools.ietf.org/html/rfc6386#section-9.6 Page 145)
// says to clamp the LHS value at 132, which is equal to dequantTableDC[117].
d.quant[i].uv[0] = dequantTableDC[clip(q+dquvDC, 0, 117)]
d.quant[i].uv[1] = dequantTableAC[clip(q+dquvAC, 0, 127)]
}
}
// The dequantization tables are specified in section 14.1.
var (
dequantTableDC = [128]uint16{
4, 5, 6, 7, 8, 9, 10, 10,
11, 12, 13, 14, 15, 16, 17, 17,
18, 19, 20, 20, 21, 21, 22, 22,
23, 23, 24, 25, 25, 26, 27, 28,
29, 30, 31, 32, 33, 34, 35, 36,
37, 37, 38, 39, 40, 41, 42, 43,
44, 45, 46, 46, 47, 48, 49, 50,
51, 52, 53, 54, 55, 56, 57, 58,
59, 60, 61, 62, 63, 64, 65, 66,
67, 68, 69, 70, 71, 72, 73, 74,
75, 76, 76, 77, 78, 79, 80, 81,
82, 83, 84, 85, 86, 87, 88, 89,
91, 93, 95, 96, 98, 100, 101, 102,
104, 106, 108, 110, 112, 114, 116, 118,
122, 124, 126, 128, 130, 132, 134, 136,
138, 140, 143, 145, 148, 151, 154, 157,
}
dequantTableAC = [128]uint16{
4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16, 17, 18, 19,
20, 21, 22, 23, 24, 25, 26, 27,
28, 29, 30, 31, 32, 33, 34, 35,
36, 37, 38, 39, 40, 41, 42, 43,
44, 45, 46, 47, 48, 49, 50, 51,
52, 53, 54, 55, 56, 57, 58, 60,
62, 64, 66, 68, 70, 72, 74, 76,
78, 80, 82, 84, 86, 88, 90, 92,
94, 96, 98, 100, 102, 104, 106, 108,
110, 112, 114, 116, 119, 122, 125, 128,
131, 134, 137, 140, 143, 146, 149, 152,
155, 158, 161, 164, 167, 170, 173, 177,
181, 185, 189, 193, 197, 201, 205, 209,
213, 217, 221, 225, 229, 234, 239, 245,
249, 254, 259, 264, 269, 274, 279, 284,
}
)

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// This file implements decoding DCT/WHT residual coefficients and
// reconstructing YCbCr data equal to predicted values plus residuals.
//
// There are 1*16*16 + 2*8*8 + 1*4*4 coefficients per macroblock:
// - 1*16*16 luma DCT coefficients,
// - 2*8*8 chroma DCT coefficients, and
// - 1*4*4 luma WHT coefficients.
// Coefficients are read in lots of 16, and the later coefficients in each lot
// are often zero.
//
// The YCbCr data consists of 1*16*16 luma values and 2*8*8 chroma values,
// plus previously decoded values along the top and left borders. The combined
// values are laid out as a [1+16+1+8][32]uint8 so that vertically adjacent
// samples are 32 bytes apart. In detail, the layout is:
//
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
// . . . . . . . a b b b b b b b b b b b b b b b b c c c c . . . . 0
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 1
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 2
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 3
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y c c c c . . . . 4
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 5
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 6
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 7
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y c c c c . . . . 8
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 9
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 10
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 11
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y c c c c . . . . 12
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 13
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 14
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 15
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 16
// . . . . . . . e f f f f f f f f . . . . . . . g h h h h h h h h 17
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 18
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 19
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 20
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 21
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 22
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 23
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 24
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 25
//
// Y, B and R are the reconstructed luma (Y) and chroma (B, R) values.
// The Y values are predicted (either as one 16x16 region or 16 4x4 regions)
// based on the row above's Y values (some combination of {abc} or {dYC}) and
// the column left's Y values (either {ad} or {bY}). Similarly, B and R values
// are predicted on the row above and column left of their respective 8x8
// region: {efi} for B, {ghj} for R.
//
// For uppermost macroblocks (i.e. those with mby == 0), the {abcefgh} values
// are initialized to 0x81. Otherwise, they are copied from the bottom row of
// the macroblock above. The {c} values are then duplicated from row 0 to rows
// 4, 8 and 12 of the ybr workspace.
// Similarly, for leftmost macroblocks (i.e. those with mbx == 0), the {adeigj}
// values are initialized to 0x7f. Otherwise, they are copied from the right
// column of the macroblock to the left.
// For the top-left macroblock (with mby == 0 && mbx == 0), {aeg} is 0x81.
//
// When moving from one macroblock to the next horizontally, the {adeigj}
// values can simply be copied from the workspace to itself, shifted by 8 or
// 16 columns. When moving from one macroblock to the next vertically,
// filtering can occur and hence the row values have to be copied from the
// post-filtered image instead of the pre-filtered workspace.
const (
bCoeffBase = 1*16*16 + 0*8*8
rCoeffBase = 1*16*16 + 1*8*8
whtCoeffBase = 1*16*16 + 2*8*8
)
const (
ybrYX = 8
ybrYY = 1
ybrBX = 8
ybrBY = 18
ybrRX = 24
ybrRY = 18
)
// prepareYBR prepares the {abcdefghij} elements of ybr.
func (d *Decoder) prepareYBR(mbx, mby int) {
if mbx == 0 {
for y := 0; y < 17; y++ {
d.ybr[y][7] = 0x81
}
for y := 17; y < 26; y++ {
d.ybr[y][7] = 0x81
d.ybr[y][23] = 0x81
}
} else {
for y := 0; y < 17; y++ {
d.ybr[y][7] = d.ybr[y][7+16]
}
for y := 17; y < 26; y++ {
d.ybr[y][7] = d.ybr[y][15]
d.ybr[y][23] = d.ybr[y][31]
}
}
if mby == 0 {
for x := 7; x < 28; x++ {
d.ybr[0][x] = 0x7f
}
for x := 7; x < 16; x++ {
d.ybr[17][x] = 0x7f
}
for x := 23; x < 32; x++ {
d.ybr[17][x] = 0x7f
}
} else {
for i := 0; i < 16; i++ {
d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+i]
}
for i := 0; i < 8; i++ {
d.ybr[17][8+i] = d.img.Cb[(8*mby-1)*d.img.CStride+8*mbx+i]
}
for i := 0; i < 8; i++ {
d.ybr[17][24+i] = d.img.Cr[(8*mby-1)*d.img.CStride+8*mbx+i]
}
if mbx == d.mbw-1 {
for i := 16; i < 20; i++ {
d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+15]
}
} else {
for i := 16; i < 20; i++ {
d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+i]
}
}
}
for y := 4; y < 16; y += 4 {
d.ybr[y][24] = d.ybr[0][24]
d.ybr[y][25] = d.ybr[0][25]
d.ybr[y][26] = d.ybr[0][26]
d.ybr[y][27] = d.ybr[0][27]
}
}
// btou converts a bool to a 0/1 value.
func btou(b bool) uint8 {
if b {
return 1
}
return 0
}
// pack packs four 0/1 values into four bits of a uint32.
func pack(x [4]uint8, shift int) uint32 {
u := uint32(x[0])<<0 | uint32(x[1])<<1 | uint32(x[2])<<2 | uint32(x[3])<<3
return u << uint(shift)
}
// unpack unpacks four 0/1 values from a four-bit value.
var unpack = [16][4]uint8{
{0, 0, 0, 0},
{1, 0, 0, 0},
{0, 1, 0, 0},
{1, 1, 0, 0},
{0, 0, 1, 0},
{1, 0, 1, 0},
{0, 1, 1, 0},
{1, 1, 1, 0},
{0, 0, 0, 1},
{1, 0, 0, 1},
{0, 1, 0, 1},
{1, 1, 0, 1},
{0, 0, 1, 1},
{1, 0, 1, 1},
{0, 1, 1, 1},
{1, 1, 1, 1},
}
var (
// The mapping from 4x4 region position to band is specified in section 13.3.
bands = [17]uint8{0, 1, 2, 3, 6, 4, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7, 0}
// Category probabilties are specified in section 13.2.
// Decoding categories 1 and 2 are done inline.
cat3456 = [4][12]uint8{
{173, 148, 140, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{176, 155, 140, 135, 0, 0, 0, 0, 0, 0, 0, 0},
{180, 157, 141, 134, 130, 0, 0, 0, 0, 0, 0, 0},
{254, 254, 243, 230, 196, 177, 153, 140, 133, 130, 129, 0},
}
// The zigzag order is:
// 0 1 5 6
// 2 4 7 12
// 3 8 11 13
// 9 10 14 15
zigzag = [16]uint8{0, 1, 4, 8, 5, 2, 3, 6, 9, 12, 13, 10, 7, 11, 14, 15}
)
// parseResiduals4 parses a 4x4 region of residual coefficients, as specified
// in section 13.3, and returns a 0/1 value indicating whether there was at
// least one non-zero coefficient.
// r is the partition to read bits from.
// plane and context describe which token probability table to use. context is
// either 0, 1 or 2, and equals how many of the macroblock left and macroblock
// above have non-zero coefficients.
// quant are the DC/AC quantization factors.
// skipFirstCoeff is whether the DC coefficient has already been parsed.
// coeffBase is the base index of d.coeff to write to.
func (d *Decoder) parseResiduals4(r *partition, plane int, context uint8, quant [2]uint16, skipFirstCoeff bool, coeffBase int) uint8 {
prob, n := &d.tokenProb[plane], 0
if skipFirstCoeff {
n = 1
}
p := prob[bands[n]][context]
if !r.readBit(p[0]) {
return 0
}
for n != 16 {
n++
if !r.readBit(p[1]) {
p = prob[bands[n]][0]
continue
}
var v uint32
if !r.readBit(p[2]) {
v = 1
p = prob[bands[n]][1]
} else {
if !r.readBit(p[3]) {
if !r.readBit(p[4]) {
v = 2
} else {
v = 3 + r.readUint(p[5], 1)
}
} else if !r.readBit(p[6]) {
if !r.readBit(p[7]) {
// Category 1.
v = 5 + r.readUint(159, 1)
} else {
// Category 2.
v = 7 + 2*r.readUint(165, 1) + r.readUint(145, 1)
}
} else {
// Categories 3, 4, 5 or 6.
b1 := r.readUint(p[8], 1)
b0 := r.readUint(p[9+b1], 1)
cat := 2*b1 + b0
tab := &cat3456[cat]
v = 0
for i := 0; tab[i] != 0; i++ {
v *= 2
v += r.readUint(tab[i], 1)
}
v += 3 + (8 << cat)
}
p = prob[bands[n]][2]
}
z := zigzag[n-1]
c := int32(v) * int32(quant[btou(z > 0)])
if r.readBit(uniformProb) {
c = -c
}
d.coeff[coeffBase+int(z)] = int16(c)
if n == 16 || !r.readBit(p[0]) {
return 1
}
}
return 1
}
// parseResiduals parses the residuals and returns whether inner loop filtering
// should be skipped for this macroblock.
func (d *Decoder) parseResiduals(mbx, mby int) (skip bool) {
partition := &d.op[mby&(d.nOP-1)]
plane := planeY1SansY2
quant := &d.quant[d.segment]
// Parse the DC coefficient of each 4x4 luma region.
if d.usePredY16 {
nz := d.parseResiduals4(partition, planeY2, d.leftMB.nzY16+d.upMB[mbx].nzY16, quant.y2, false, whtCoeffBase)
d.leftMB.nzY16 = nz
d.upMB[mbx].nzY16 = nz
d.inverseWHT16()
plane = planeY1WithY2
}
var (
nzDC, nzAC [4]uint8
nzDCMask, nzACMask uint32
coeffBase int
)
// Parse the luma coefficients.
lnz := unpack[d.leftMB.nzMask&0x0f]
unz := unpack[d.upMB[mbx].nzMask&0x0f]
for y := 0; y < 4; y++ {
nz := lnz[y]
for x := 0; x < 4; x++ {
nz = d.parseResiduals4(partition, plane, nz+unz[x], quant.y1, d.usePredY16, coeffBase)
unz[x] = nz
nzAC[x] = nz
nzDC[x] = btou(d.coeff[coeffBase] != 0)
coeffBase += 16
}
lnz[y] = nz
nzDCMask |= pack(nzDC, y*4)
nzACMask |= pack(nzAC, y*4)
}
lnzMask := pack(lnz, 0)
unzMask := pack(unz, 0)
// Parse the chroma coefficients.
lnz = unpack[d.leftMB.nzMask>>4]
unz = unpack[d.upMB[mbx].nzMask>>4]
for c := 0; c < 4; c += 2 {
for y := 0; y < 2; y++ {
nz := lnz[y+c]
for x := 0; x < 2; x++ {
nz = d.parseResiduals4(partition, planeUV, nz+unz[x+c], quant.uv, false, coeffBase)
unz[x+c] = nz
nzAC[y*2+x] = nz
nzDC[y*2+x] = btou(d.coeff[coeffBase] != 0)
coeffBase += 16
}
lnz[y+c] = nz
}
nzDCMask |= pack(nzDC, 16+c*2)
nzACMask |= pack(nzAC, 16+c*2)
}
lnzMask |= pack(lnz, 4)
unzMask |= pack(unz, 4)
// Save decoder state.
d.leftMB.nzMask = uint8(lnzMask)
d.upMB[mbx].nzMask = uint8(unzMask)
d.nzDCMask = nzDCMask
d.nzACMask = nzACMask
// Section 15.1 of the spec says that "Steps 2 and 4 [of the loop filter]
// are skipped... [if] there is no DCT coefficient coded for the whole
// macroblock."
return nzDCMask == 0 && nzACMask == 0
}
// reconstructMacroblock applies the predictor functions and adds the inverse-
// DCT transformed residuals to recover the YCbCr data.
func (d *Decoder) reconstructMacroblock(mbx, mby int) {
if d.usePredY16 {
p := checkTopLeftPred(mbx, mby, d.predY16)
predFunc16[p](d, 1, 8)
for j := 0; j < 4; j++ {
for i := 0; i < 4; i++ {
n := 4*j + i
y := 4*j + 1
x := 4*i + 8
mask := uint32(1) << uint(n)
if d.nzACMask&mask != 0 {
d.inverseDCT4(y, x, 16*n)
} else if d.nzDCMask&mask != 0 {
d.inverseDCT4DCOnly(y, x, 16*n)
}
}
}
} else {
for j := 0; j < 4; j++ {
for i := 0; i < 4; i++ {
n := 4*j + i
y := 4*j + 1
x := 4*i + 8
predFunc4[d.predY4[j][i]](d, y, x)
mask := uint32(1) << uint(n)
if d.nzACMask&mask != 0 {
d.inverseDCT4(y, x, 16*n)
} else if d.nzDCMask&mask != 0 {
d.inverseDCT4DCOnly(y, x, 16*n)
}
}
}
}
p := checkTopLeftPred(mbx, mby, d.predC8)
predFunc8[p](d, ybrBY, ybrBX)
if d.nzACMask&0x0f0000 != 0 {
d.inverseDCT8(ybrBY, ybrBX, bCoeffBase)
} else if d.nzDCMask&0x0f0000 != 0 {
d.inverseDCT8DCOnly(ybrBY, ybrBX, bCoeffBase)
}
predFunc8[p](d, ybrRY, ybrRX)
if d.nzACMask&0xf00000 != 0 {
d.inverseDCT8(ybrRY, ybrRX, rCoeffBase)
} else if d.nzDCMask&0xf00000 != 0 {
d.inverseDCT8DCOnly(ybrRY, ybrRX, rCoeffBase)
}
}
// reconstruct reconstructs one macroblock and returns whether inner loop
// filtering should be skipped for it.
func (d *Decoder) reconstruct(mbx, mby int) (skip bool) {
if d.segmentHeader.updateMap {
if !d.fp.readBit(d.segmentHeader.prob[0]) {
d.segment = int(d.fp.readUint(d.segmentHeader.prob[1], 1))
} else {
d.segment = int(d.fp.readUint(d.segmentHeader.prob[2], 1)) + 2
}
}
if d.useSkipProb {
skip = d.fp.readBit(d.skipProb)
}
// Prepare the workspace.
for i := range d.coeff {
d.coeff[i] = 0
}
d.prepareYBR(mbx, mby)
// Parse the predictor modes.
d.usePredY16 = d.fp.readBit(145)
if d.usePredY16 {
d.parsePredModeY16(mbx)
} else {
d.parsePredModeY4(mbx)
}
d.parsePredModeC8()
// Parse the residuals.
if !skip {
skip = d.parseResiduals(mbx, mby)
} else {
if d.usePredY16 {
d.leftMB.nzY16 = 0
d.upMB[mbx].nzY16 = 0
}
d.leftMB.nzMask = 0
d.upMB[mbx].nzMask = 0
d.nzDCMask = 0
d.nzACMask = 0
}
// Reconstruct the YCbCr data and copy it to the image.
d.reconstructMacroblock(mbx, mby)
for i, y := (mby*d.img.YStride+mbx)*16, 0; y < 16; i, y = i+d.img.YStride, y+1 {
copy(d.img.Y[i:i+16], d.ybr[ybrYY+y][ybrYX:ybrYX+16])
}
for i, y := (mby*d.img.CStride+mbx)*8, 0; y < 8; i, y = i+d.img.CStride, y+1 {
copy(d.img.Cb[i:i+8], d.ybr[ybrBY+y][ybrBX:ybrBX+8])
copy(d.img.Cr[i:i+8], d.ybr[ybrRY+y][ybrRX:ybrRX+8])
}
return skip
}

381
vendor/golang.org/x/image/vp8/token.go generated vendored Normal file
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@ -0,0 +1,381 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// This file contains token probabilities for decoding DCT/WHT coefficients, as
// specified in chapter 13.
func (d *Decoder) parseTokenProb() {
for i := range d.tokenProb {
for j := range d.tokenProb[i] {
for k := range d.tokenProb[i][j] {
for l := range d.tokenProb[i][j][k] {
if d.fp.readBit(tokenProbUpdateProb[i][j][k][l]) {
d.tokenProb[i][j][k][l] = uint8(d.fp.readUint(uniformProb, 8))
}
}
}
}
}
}
// The plane enumeration is specified in section 13.3.
const (
planeY1WithY2 = iota
planeY2
planeUV
planeY1SansY2
nPlane
)
const (
nBand = 8
nContext = 3
nProb = 11
)
// Token probability update probabilities are specified in section 13.4.
var tokenProbUpdateProb = [nPlane][nBand][nContext][nProb]uint8{
{
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{176, 246, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{223, 241, 252, 255, 255, 255, 255, 255, 255, 255, 255},
{249, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 244, 252, 255, 255, 255, 255, 255, 255, 255, 255},
{234, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{253, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 246, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{239, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 248, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{251, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{251, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 254, 253, 255, 254, 255, 255, 255, 255, 255, 255},
{250, 255, 254, 255, 254, 255, 255, 255, 255, 255, 255},
{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
},
{
{
{217, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{225, 252, 241, 253, 255, 255, 254, 255, 255, 255, 255},
{234, 250, 241, 250, 253, 255, 253, 254, 255, 255, 255},
},
{
{255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{223, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{238, 253, 254, 254, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 248, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{249, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 253, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{247, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{252, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{253, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 254, 253, 255, 255, 255, 255, 255, 255, 255, 255},
{250, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
},
{
{
{186, 251, 250, 255, 255, 255, 255, 255, 255, 255, 255},
{234, 251, 244, 254, 255, 255, 255, 255, 255, 255, 255},
{251, 251, 243, 253, 254, 255, 254, 255, 255, 255, 255},
},
{
{255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{236, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{251, 253, 253, 254, 254, 255, 255, 255, 255, 255, 255},
},
{
{255, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
},
{
{
{248, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{250, 254, 252, 254, 255, 255, 255, 255, 255, 255, 255},
{248, 254, 249, 253, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255},
{246, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255},
{252, 254, 251, 254, 254, 255, 255, 255, 255, 255, 255},
},
{
{255, 254, 252, 255, 255, 255, 255, 255, 255, 255, 255},
{248, 254, 253, 255, 255, 255, 255, 255, 255, 255, 255},
{253, 255, 254, 254, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 251, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{245, 251, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{253, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 251, 253, 255, 255, 255, 255, 255, 255, 255, 255},
{252, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 252, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{249, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 253, 255, 255, 255, 255, 255, 255, 255, 255},
{250, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
},
}
// Default token probabilities are specified in section 13.5.
var defaultTokenProb = [nPlane][nBand][nContext][nProb]uint8{
{
{
{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
},
{
{253, 136, 254, 255, 228, 219, 128, 128, 128, 128, 128},
{189, 129, 242, 255, 227, 213, 255, 219, 128, 128, 128},
{106, 126, 227, 252, 214, 209, 255, 255, 128, 128, 128},
},
{
{1, 98, 248, 255, 236, 226, 255, 255, 128, 128, 128},
{181, 133, 238, 254, 221, 234, 255, 154, 128, 128, 128},
{78, 134, 202, 247, 198, 180, 255, 219, 128, 128, 128},
},
{
{1, 185, 249, 255, 243, 255, 128, 128, 128, 128, 128},
{184, 150, 247, 255, 236, 224, 128, 128, 128, 128, 128},
{77, 110, 216, 255, 236, 230, 128, 128, 128, 128, 128},
},
{
{1, 101, 251, 255, 241, 255, 128, 128, 128, 128, 128},
{170, 139, 241, 252, 236, 209, 255, 255, 128, 128, 128},
{37, 116, 196, 243, 228, 255, 255, 255, 128, 128, 128},
},
{
{1, 204, 254, 255, 245, 255, 128, 128, 128, 128, 128},
{207, 160, 250, 255, 238, 128, 128, 128, 128, 128, 128},
{102, 103, 231, 255, 211, 171, 128, 128, 128, 128, 128},
},
{
{1, 152, 252, 255, 240, 255, 128, 128, 128, 128, 128},
{177, 135, 243, 255, 234, 225, 128, 128, 128, 128, 128},
{80, 129, 211, 255, 194, 224, 128, 128, 128, 128, 128},
},
{
{1, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
{246, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
{255, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
},
},
{
{
{198, 35, 237, 223, 193, 187, 162, 160, 145, 155, 62},
{131, 45, 198, 221, 172, 176, 220, 157, 252, 221, 1},
{68, 47, 146, 208, 149, 167, 221, 162, 255, 223, 128},
},
{
{1, 149, 241, 255, 221, 224, 255, 255, 128, 128, 128},
{184, 141, 234, 253, 222, 220, 255, 199, 128, 128, 128},
{81, 99, 181, 242, 176, 190, 249, 202, 255, 255, 128},
},
{
{1, 129, 232, 253, 214, 197, 242, 196, 255, 255, 128},
{99, 121, 210, 250, 201, 198, 255, 202, 128, 128, 128},
{23, 91, 163, 242, 170, 187, 247, 210, 255, 255, 128},
},
{
{1, 200, 246, 255, 234, 255, 128, 128, 128, 128, 128},
{109, 178, 241, 255, 231, 245, 255, 255, 128, 128, 128},
{44, 130, 201, 253, 205, 192, 255, 255, 128, 128, 128},
},
{
{1, 132, 239, 251, 219, 209, 255, 165, 128, 128, 128},
{94, 136, 225, 251, 218, 190, 255, 255, 128, 128, 128},
{22, 100, 174, 245, 186, 161, 255, 199, 128, 128, 128},
},
{
{1, 182, 249, 255, 232, 235, 128, 128, 128, 128, 128},
{124, 143, 241, 255, 227, 234, 128, 128, 128, 128, 128},
{35, 77, 181, 251, 193, 211, 255, 205, 128, 128, 128},
},
{
{1, 157, 247, 255, 236, 231, 255, 255, 128, 128, 128},
{121, 141, 235, 255, 225, 227, 255, 255, 128, 128, 128},
{45, 99, 188, 251, 195, 217, 255, 224, 128, 128, 128},
},
{
{1, 1, 251, 255, 213, 255, 128, 128, 128, 128, 128},
{203, 1, 248, 255, 255, 128, 128, 128, 128, 128, 128},
{137, 1, 177, 255, 224, 255, 128, 128, 128, 128, 128},
},
},
{
{
{253, 9, 248, 251, 207, 208, 255, 192, 128, 128, 128},
{175, 13, 224, 243, 193, 185, 249, 198, 255, 255, 128},
{73, 17, 171, 221, 161, 179, 236, 167, 255, 234, 128},
},
{
{1, 95, 247, 253, 212, 183, 255, 255, 128, 128, 128},
{239, 90, 244, 250, 211, 209, 255, 255, 128, 128, 128},
{155, 77, 195, 248, 188, 195, 255, 255, 128, 128, 128},
},
{
{1, 24, 239, 251, 218, 219, 255, 205, 128, 128, 128},
{201, 51, 219, 255, 196, 186, 128, 128, 128, 128, 128},
{69, 46, 190, 239, 201, 218, 255, 228, 128, 128, 128},
},
{
{1, 191, 251, 255, 255, 128, 128, 128, 128, 128, 128},
{223, 165, 249, 255, 213, 255, 128, 128, 128, 128, 128},
{141, 124, 248, 255, 255, 128, 128, 128, 128, 128, 128},
},
{
{1, 16, 248, 255, 255, 128, 128, 128, 128, 128, 128},
{190, 36, 230, 255, 236, 255, 128, 128, 128, 128, 128},
{149, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
},
{
{1, 226, 255, 128, 128, 128, 128, 128, 128, 128, 128},
{247, 192, 255, 128, 128, 128, 128, 128, 128, 128, 128},
{240, 128, 255, 128, 128, 128, 128, 128, 128, 128, 128},
},
{
{1, 134, 252, 255, 255, 128, 128, 128, 128, 128, 128},
{213, 62, 250, 255, 255, 128, 128, 128, 128, 128, 128},
{55, 93, 255, 128, 128, 128, 128, 128, 128, 128, 128},
},
{
{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
},
},
{
{
{202, 24, 213, 235, 186, 191, 220, 160, 240, 175, 255},
{126, 38, 182, 232, 169, 184, 228, 174, 255, 187, 128},
{61, 46, 138, 219, 151, 178, 240, 170, 255, 216, 128},
},
{
{1, 112, 230, 250, 199, 191, 247, 159, 255, 255, 128},
{166, 109, 228, 252, 211, 215, 255, 174, 128, 128, 128},
{39, 77, 162, 232, 172, 180, 245, 178, 255, 255, 128},
},
{
{1, 52, 220, 246, 198, 199, 249, 220, 255, 255, 128},
{124, 74, 191, 243, 183, 193, 250, 221, 255, 255, 128},
{24, 71, 130, 219, 154, 170, 243, 182, 255, 255, 128},
},
{
{1, 182, 225, 249, 219, 240, 255, 224, 128, 128, 128},
{149, 150, 226, 252, 216, 205, 255, 171, 128, 128, 128},
{28, 108, 170, 242, 183, 194, 254, 223, 255, 255, 128},
},
{
{1, 81, 230, 252, 204, 203, 255, 192, 128, 128, 128},
{123, 102, 209, 247, 188, 196, 255, 233, 128, 128, 128},
{20, 95, 153, 243, 164, 173, 255, 203, 128, 128, 128},
},
{
{1, 222, 248, 255, 216, 213, 128, 128, 128, 128, 128},
{168, 175, 246, 252, 235, 205, 255, 255, 128, 128, 128},
{47, 116, 215, 255, 211, 212, 255, 255, 128, 128, 128},
},
{
{1, 121, 236, 253, 212, 214, 255, 255, 128, 128, 128},
{141, 84, 213, 252, 201, 202, 255, 219, 128, 128, 128},
{42, 80, 160, 240, 162, 185, 255, 205, 128, 128, 128},
},
{
{1, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
{244, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
{238, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
},
},
}

603
vendor/golang.org/x/image/vp8l/decode.go generated vendored Normal file
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@ -0,0 +1,603 @@
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package vp8l implements a decoder for the VP8L lossless image format.
//
// The VP8L specification is at:
// https://developers.google.com/speed/webp/docs/riff_container
package vp8l // import "golang.org/x/image/vp8l"
import (
"bufio"
"errors"
"image"
"image/color"
"io"
)
var (
errInvalidCodeLengths = errors.New("vp8l: invalid code lengths")
errInvalidHuffmanTree = errors.New("vp8l: invalid Huffman tree")
)
// colorCacheMultiplier is the multiplier used for the color cache hash
// function, specified in section 4.2.3.
const colorCacheMultiplier = 0x1e35a7bd
// distanceMapTable is the look-up table for distanceMap.
var distanceMapTable = [120]uint8{
0x18, 0x07, 0x17, 0x19, 0x28, 0x06, 0x27, 0x29, 0x16, 0x1a,
0x26, 0x2a, 0x38, 0x05, 0x37, 0x39, 0x15, 0x1b, 0x36, 0x3a,
0x25, 0x2b, 0x48, 0x04, 0x47, 0x49, 0x14, 0x1c, 0x35, 0x3b,
0x46, 0x4a, 0x24, 0x2c, 0x58, 0x45, 0x4b, 0x34, 0x3c, 0x03,
0x57, 0x59, 0x13, 0x1d, 0x56, 0x5a, 0x23, 0x2d, 0x44, 0x4c,
0x55, 0x5b, 0x33, 0x3d, 0x68, 0x02, 0x67, 0x69, 0x12, 0x1e,
0x66, 0x6a, 0x22, 0x2e, 0x54, 0x5c, 0x43, 0x4d, 0x65, 0x6b,
0x32, 0x3e, 0x78, 0x01, 0x77, 0x79, 0x53, 0x5d, 0x11, 0x1f,
0x64, 0x6c, 0x42, 0x4e, 0x76, 0x7a, 0x21, 0x2f, 0x75, 0x7b,
0x31, 0x3f, 0x63, 0x6d, 0x52, 0x5e, 0x00, 0x74, 0x7c, 0x41,
0x4f, 0x10, 0x20, 0x62, 0x6e, 0x30, 0x73, 0x7d, 0x51, 0x5f,
0x40, 0x72, 0x7e, 0x61, 0x6f, 0x50, 0x71, 0x7f, 0x60, 0x70,
}
// distanceMap maps a LZ77 backwards reference distance to a two-dimensional
// pixel offset, specified in section 4.2.2.
func distanceMap(w int32, code uint32) int32 {
if int32(code) > int32(len(distanceMapTable)) {
return int32(code) - int32(len(distanceMapTable))
}
distCode := int32(distanceMapTable[code-1])
yOffset := distCode >> 4
xOffset := 8 - distCode&0xf
if d := yOffset*w + xOffset; d >= 1 {
return d
}
return 1
}
// decoder holds the bit-stream for a VP8L image.
type decoder struct {
r io.ByteReader
bits uint32
nBits uint32
}
// read reads the next n bits from the decoder's bit-stream.
func (d *decoder) read(n uint32) (uint32, error) {
for d.nBits < n {
c, err := d.r.ReadByte()
if err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return 0, err
}
d.bits |= uint32(c) << d.nBits
d.nBits += 8
}
u := d.bits & (1<<n - 1)
d.bits >>= n
d.nBits -= n
return u, nil
}
// decodeTransform decodes the next transform and the width of the image after
// transformation (or equivalently, before inverse transformation), specified
// in section 3.
func (d *decoder) decodeTransform(w int32, h int32) (t transform, newWidth int32, err error) {
t.oldWidth = w
t.transformType, err = d.read(2)
if err != nil {
return transform{}, 0, err
}
switch t.transformType {
case transformTypePredictor, transformTypeCrossColor:
t.bits, err = d.read(3)
if err != nil {
return transform{}, 0, err
}
t.bits += 2
t.pix, err = d.decodePix(nTiles(w, t.bits), nTiles(h, t.bits), 0, false)
if err != nil {
return transform{}, 0, err
}
case transformTypeSubtractGreen:
// No-op.
case transformTypeColorIndexing:
nColors, err := d.read(8)
if err != nil {
return transform{}, 0, err
}
nColors++
t.bits = 0
switch {
case nColors <= 2:
t.bits = 3
case nColors <= 4:
t.bits = 2
case nColors <= 16:
t.bits = 1
}
w = nTiles(w, t.bits)
pix, err := d.decodePix(int32(nColors), 1, 4*256, false)
if err != nil {
return transform{}, 0, err
}
for p := 4; p < len(pix); p += 4 {
pix[p+0] += pix[p-4]
pix[p+1] += pix[p-3]
pix[p+2] += pix[p-2]
pix[p+3] += pix[p-1]
}
// The spec says that "if the index is equal or larger than color_table_size,
// the argb color value should be set to 0x00000000 (transparent black)."
// We re-slice up to 256 4-byte pixels.
t.pix = pix[:4*256]
}
return t, w, nil
}
// repeatsCodeLength is the minimum code length for repeated codes.
const repeatsCodeLength = 16
// These magic numbers are specified at the end of section 5.2.2.
// The 3-length arrays apply to code lengths >= repeatsCodeLength.
var (
codeLengthCodeOrder = [19]uint8{
17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
}
repeatBits = [3]uint8{2, 3, 7}
repeatOffsets = [3]uint8{3, 3, 11}
)
// decodeCodeLengths decodes a Huffman tree's code lengths which are themselves
// encoded via a Huffman tree, specified in section 5.2.2.
func (d *decoder) decodeCodeLengths(dst []uint32, codeLengthCodeLengths []uint32) error {
h := hTree{}
if err := h.build(codeLengthCodeLengths); err != nil {
return err
}
maxSymbol := len(dst)
useLength, err := d.read(1)
if err != nil {
return err
}
if useLength != 0 {
n, err := d.read(3)
if err != nil {
return err
}
n = 2 + 2*n
ms, err := d.read(n)
if err != nil {
return err
}
maxSymbol = int(ms) + 2
if maxSymbol > len(dst) {
return errInvalidCodeLengths
}
}
// The spec says that "if code 16 [meaning repeat] is used before
// a non-zero value has been emitted, a value of 8 is repeated."
prevCodeLength := uint32(8)
for symbol := 0; symbol < len(dst); {
if maxSymbol == 0 {
break
}
maxSymbol--
codeLength, err := h.next(d)
if err != nil {
return err
}
if codeLength < repeatsCodeLength {
dst[symbol] = codeLength
symbol++
if codeLength != 0 {
prevCodeLength = codeLength
}
continue
}
repeat, err := d.read(uint32(repeatBits[codeLength-repeatsCodeLength]))
if err != nil {
return err
}
repeat += uint32(repeatOffsets[codeLength-repeatsCodeLength])
if symbol+int(repeat) > len(dst) {
return errInvalidCodeLengths
}
// A code length of 16 repeats the previous non-zero code.
// A code length of 17 or 18 repeats zeroes.
cl := uint32(0)
if codeLength == 16 {
cl = prevCodeLength
}
for ; repeat > 0; repeat-- {
dst[symbol] = cl
symbol++
}
}
return nil
}
// decodeHuffmanTree decodes a Huffman tree into h.
func (d *decoder) decodeHuffmanTree(h *hTree, alphabetSize uint32) error {
useSimple, err := d.read(1)
if err != nil {
return err
}
if useSimple != 0 {
nSymbols, err := d.read(1)
if err != nil {
return err
}
nSymbols++
firstSymbolLengthCode, err := d.read(1)
if err != nil {
return err
}
firstSymbolLengthCode = 7*firstSymbolLengthCode + 1
var symbols [2]uint32
symbols[0], err = d.read(firstSymbolLengthCode)
if err != nil {
return err
}
if nSymbols == 2 {
symbols[1], err = d.read(8)
if err != nil {
return err
}
}
return h.buildSimple(nSymbols, symbols, alphabetSize)
}
nCodes, err := d.read(4)
if err != nil {
return err
}
nCodes += 4
if int(nCodes) > len(codeLengthCodeOrder) {
return errInvalidHuffmanTree
}
codeLengthCodeLengths := [len(codeLengthCodeOrder)]uint32{}
for i := uint32(0); i < nCodes; i++ {
codeLengthCodeLengths[codeLengthCodeOrder[i]], err = d.read(3)
if err != nil {
return err
}
}
codeLengths := make([]uint32, alphabetSize)
if err = d.decodeCodeLengths(codeLengths, codeLengthCodeLengths[:]); err != nil {
return err
}
return h.build(codeLengths)
}
const (
huffGreen = 0
huffRed = 1
huffBlue = 2
huffAlpha = 3
huffDistance = 4
nHuff = 5
)
// hGroup is an array of 5 Huffman trees.
type hGroup [nHuff]hTree
// decodeHuffmanGroups decodes the one or more hGroups used to decode the pixel
// data. If one hGroup is used for the entire image, then hPix and hBits will
// be zero. If more than one hGroup is used, then hPix contains the meta-image
// that maps tiles to hGroup index, and hBits contains the log-2 tile size.
func (d *decoder) decodeHuffmanGroups(w int32, h int32, topLevel bool, ccBits uint32) (
hGroups []hGroup, hPix []byte, hBits uint32, err error) {
maxHGroupIndex := 0
if topLevel {
useMeta, err := d.read(1)
if err != nil {
return nil, nil, 0, err
}
if useMeta != 0 {
hBits, err = d.read(3)
if err != nil {
return nil, nil, 0, err
}
hBits += 2
hPix, err = d.decodePix(nTiles(w, hBits), nTiles(h, hBits), 0, false)
if err != nil {
return nil, nil, 0, err
}
for p := 0; p < len(hPix); p += 4 {
i := int(hPix[p])<<8 | int(hPix[p+1])
if maxHGroupIndex < i {
maxHGroupIndex = i
}
}
}
}
hGroups = make([]hGroup, maxHGroupIndex+1)
for i := range hGroups {
for j, alphabetSize := range alphabetSizes {
if j == 0 && ccBits > 0 {
alphabetSize += 1 << ccBits
}
if err := d.decodeHuffmanTree(&hGroups[i][j], alphabetSize); err != nil {
return nil, nil, 0, err
}
}
}
return hGroups, hPix, hBits, nil
}
const (
nLiteralCodes = 256
nLengthCodes = 24
nDistanceCodes = 40
)
var alphabetSizes = [nHuff]uint32{
nLiteralCodes + nLengthCodes,
nLiteralCodes,
nLiteralCodes,
nLiteralCodes,
nDistanceCodes,
}
// decodePix decodes pixel data, specified in section 5.2.2.
func (d *decoder) decodePix(w int32, h int32, minCap int32, topLevel bool) ([]byte, error) {
// Decode the color cache parameters.
ccBits, ccShift, ccEntries := uint32(0), uint32(0), ([]uint32)(nil)
useColorCache, err := d.read(1)
if err != nil {
return nil, err
}
if useColorCache != 0 {
ccBits, err = d.read(4)
if err != nil {
return nil, err
}
if ccBits < 1 || 11 < ccBits {
return nil, errors.New("vp8l: invalid color cache parameters")
}
ccShift = 32 - ccBits
ccEntries = make([]uint32, 1<<ccBits)
}
// Decode the Huffman groups.
hGroups, hPix, hBits, err := d.decodeHuffmanGroups(w, h, topLevel, ccBits)
if err != nil {
return nil, err
}
hMask, tilesPerRow := int32(0), int32(0)
if hBits != 0 {
hMask, tilesPerRow = 1<<hBits-1, nTiles(w, hBits)
}
// Decode the pixels.
if minCap < 4*w*h {
minCap = 4 * w * h
}
pix := make([]byte, 4*w*h, minCap)
p, cachedP := 0, 0
x, y := int32(0), int32(0)
hg, lookupHG := &hGroups[0], hMask != 0
for p < len(pix) {
if lookupHG {
i := 4 * (tilesPerRow*(y>>hBits) + (x >> hBits))
hg = &hGroups[uint32(hPix[i])<<8|uint32(hPix[i+1])]
}
green, err := hg[huffGreen].next(d)
if err != nil {
return nil, err
}
switch {
case green < nLiteralCodes:
// We have a literal pixel.
red, err := hg[huffRed].next(d)
if err != nil {
return nil, err
}
blue, err := hg[huffBlue].next(d)
if err != nil {
return nil, err
}
alpha, err := hg[huffAlpha].next(d)
if err != nil {
return nil, err
}
pix[p+0] = uint8(red)
pix[p+1] = uint8(green)
pix[p+2] = uint8(blue)
pix[p+3] = uint8(alpha)
p += 4
x++
if x == w {
x, y = 0, y+1
}
lookupHG = hMask != 0 && x&hMask == 0
case green < nLiteralCodes+nLengthCodes:
// We have a LZ77 backwards reference.
length, err := d.lz77Param(green - nLiteralCodes)
if err != nil {
return nil, err
}
distSym, err := hg[huffDistance].next(d)
if err != nil {
return nil, err
}
distCode, err := d.lz77Param(distSym)
if err != nil {
return nil, err
}
dist := distanceMap(w, distCode)
pEnd := p + 4*int(length)
q := p - 4*int(dist)
qEnd := pEnd - 4*int(dist)
if p < 0 || len(pix) < pEnd || q < 0 || len(pix) < qEnd {
return nil, errors.New("vp8l: invalid LZ77 parameters")
}
for ; p < pEnd; p, q = p+1, q+1 {
pix[p] = pix[q]
}
x += int32(length)
for x >= w {
x, y = x-w, y+1
}
lookupHG = hMask != 0
default:
// We have a color cache lookup. First, insert previous pixels
// into the cache. Note that VP8L assumes ARGB order, but the
// Go image.RGBA type is in RGBA order.
for ; cachedP < p; cachedP += 4 {
argb := uint32(pix[cachedP+0])<<16 |
uint32(pix[cachedP+1])<<8 |
uint32(pix[cachedP+2])<<0 |
uint32(pix[cachedP+3])<<24
ccEntries[(argb*colorCacheMultiplier)>>ccShift] = argb
}
green -= nLiteralCodes + nLengthCodes
if int(green) >= len(ccEntries) {
return nil, errors.New("vp8l: invalid color cache index")
}
argb := ccEntries[green]
pix[p+0] = uint8(argb >> 16)
pix[p+1] = uint8(argb >> 8)
pix[p+2] = uint8(argb >> 0)
pix[p+3] = uint8(argb >> 24)
p += 4
x++
if x == w {
x, y = 0, y+1
}
lookupHG = hMask != 0 && x&hMask == 0
}
}
return pix, nil
}
// lz77Param returns the next LZ77 parameter: a length or a distance, specified
// in section 4.2.2.
func (d *decoder) lz77Param(symbol uint32) (uint32, error) {
if symbol < 4 {
return symbol + 1, nil
}
extraBits := (symbol - 2) >> 1
offset := (2 + symbol&1) << extraBits
n, err := d.read(extraBits)
if err != nil {
return 0, err
}
return offset + n + 1, nil
}
// decodeHeader decodes the VP8L header from r.
func decodeHeader(r io.Reader) (d *decoder, w int32, h int32, err error) {
rr, ok := r.(io.ByteReader)
if !ok {
rr = bufio.NewReader(r)
}
d = &decoder{r: rr}
magic, err := d.read(8)
if err != nil {
return nil, 0, 0, err
}
if magic != 0x2f {
return nil, 0, 0, errors.New("vp8l: invalid header")
}
width, err := d.read(14)
if err != nil {
return nil, 0, 0, err
}
width++
height, err := d.read(14)
if err != nil {
return nil, 0, 0, err
}
height++
_, err = d.read(1) // Read and ignore the hasAlpha hint.
if err != nil {
return nil, 0, 0, err
}
version, err := d.read(3)
if err != nil {
return nil, 0, 0, err
}
if version != 0 {
return nil, 0, 0, errors.New("vp8l: invalid version")
}
return d, int32(width), int32(height), nil
}
// DecodeConfig decodes the color model and dimensions of a VP8L image from r.
func DecodeConfig(r io.Reader) (image.Config, error) {
_, w, h, err := decodeHeader(r)
if err != nil {
return image.Config{}, err
}
return image.Config{
ColorModel: color.NRGBAModel,
Width: int(w),
Height: int(h),
}, nil
}
// Decode decodes a VP8L image from r.
func Decode(r io.Reader) (image.Image, error) {
d, w, h, err := decodeHeader(r)
if err != nil {
return nil, err
}
// Decode the transforms.
var (
nTransforms int
transforms [nTransformTypes]transform
transformsSeen [nTransformTypes]bool
originalW = w
)
for {
more, err := d.read(1)
if err != nil {
return nil, err
}
if more == 0 {
break
}
var t transform
t, w, err = d.decodeTransform(w, h)
if err != nil {
return nil, err
}
if transformsSeen[t.transformType] {
return nil, errors.New("vp8l: repeated transform")
}
transformsSeen[t.transformType] = true
transforms[nTransforms] = t
nTransforms++
}
// Decode the transformed pixels.
pix, err := d.decodePix(w, h, 0, true)
if err != nil {
return nil, err
}
// Apply the inverse transformations.
for i := nTransforms - 1; i >= 0; i-- {
t := &transforms[i]
pix = inverseTransforms[t.transformType](t, pix, h)
}
return &image.NRGBA{
Pix: pix,
Stride: 4 * int(originalW),
Rect: image.Rect(0, 0, int(originalW), int(h)),
}, nil
}

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vendor/golang.org/x/image/vp8l/huffman.go generated vendored Normal file
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@ -0,0 +1,245 @@
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8l
import (
"io"
)
// reverseBits reverses the bits in a byte.
var reverseBits = [256]uint8{
0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0, 0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8, 0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4, 0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec, 0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2, 0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea, 0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6, 0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee, 0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1, 0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9, 0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5, 0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed, 0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3, 0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb, 0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7, 0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef, 0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
}
// hNode is a node in a Huffman tree.
type hNode struct {
// symbol is the symbol held by this node.
symbol uint32
// children, if positive, is the hTree.nodes index of the first of
// this node's two children. Zero means an uninitialized node,
// and -1 means a leaf node.
children int32
}
const leafNode = -1
// lutSize is the log-2 size of an hTree's look-up table.
const lutSize, lutMask = 7, 1<<7 - 1
// hTree is a Huffman tree.
type hTree struct {
// nodes are the nodes of the Huffman tree. During construction,
// len(nodes) grows from 1 up to cap(nodes) by steps of two.
// After construction, len(nodes) == cap(nodes), and both equal
// 2*theNumberOfSymbols - 1.
nodes []hNode
// lut is a look-up table for walking the nodes. The x in lut[x] is
// the next lutSize bits in the bit-stream. The low 8 bits of lut[x]
// equals 1 plus the number of bits in the next code, or 0 if the
// next code requires more than lutSize bits. The high 24 bits are:
// - the symbol, if the code requires lutSize or fewer bits, or
// - the hTree.nodes index to start the tree traversal from, if
// the next code requires more than lutSize bits.
lut [1 << lutSize]uint32
}
// insert inserts into the hTree a symbol whose encoding is the least
// significant codeLength bits of code.
func (h *hTree) insert(symbol uint32, code uint32, codeLength uint32) error {
if symbol > 0xffff || codeLength > 0xfe {
return errInvalidHuffmanTree
}
baseCode := uint32(0)
if codeLength > lutSize {
baseCode = uint32(reverseBits[(code>>(codeLength-lutSize))&0xff]) >> (8 - lutSize)
} else {
baseCode = uint32(reverseBits[code&0xff]) >> (8 - codeLength)
for i := 0; i < 1<<(lutSize-codeLength); i++ {
h.lut[baseCode|uint32(i)<<codeLength] = symbol<<8 | (codeLength + 1)
}
}
n := uint32(0)
for jump := lutSize; codeLength > 0; {
codeLength--
if int(n) > len(h.nodes) {
return errInvalidHuffmanTree
}
switch h.nodes[n].children {
case leafNode:
return errInvalidHuffmanTree
case 0:
if len(h.nodes) == cap(h.nodes) {
return errInvalidHuffmanTree
}
// Create two empty child nodes.
h.nodes[n].children = int32(len(h.nodes))
h.nodes = h.nodes[:len(h.nodes)+2]
}
n = uint32(h.nodes[n].children) + 1&(code>>codeLength)
jump--
if jump == 0 && h.lut[baseCode] == 0 {
h.lut[baseCode] = n << 8
}
}
switch h.nodes[n].children {
case leafNode:
// No-op.
case 0:
// Turn the uninitialized node into a leaf.
h.nodes[n].children = leafNode
default:
return errInvalidHuffmanTree
}
h.nodes[n].symbol = symbol
return nil
}
// codeLengthsToCodes returns the canonical Huffman codes implied by the
// sequence of code lengths.
func codeLengthsToCodes(codeLengths []uint32) ([]uint32, error) {
maxCodeLength := uint32(0)
for _, cl := range codeLengths {
if maxCodeLength < cl {
maxCodeLength = cl
}
}
const maxAllowedCodeLength = 15
if len(codeLengths) == 0 || maxCodeLength > maxAllowedCodeLength {
return nil, errInvalidHuffmanTree
}
histogram := [maxAllowedCodeLength + 1]uint32{}
for _, cl := range codeLengths {
histogram[cl]++
}
currCode, nextCodes := uint32(0), [maxAllowedCodeLength + 1]uint32{}
for cl := 1; cl < len(nextCodes); cl++ {
currCode = (currCode + histogram[cl-1]) << 1
nextCodes[cl] = currCode
}
codes := make([]uint32, len(codeLengths))
for symbol, cl := range codeLengths {
if cl > 0 {
codes[symbol] = nextCodes[cl]
nextCodes[cl]++
}
}
return codes, nil
}
// build builds a canonical Huffman tree from the given code lengths.
func (h *hTree) build(codeLengths []uint32) error {
// Calculate the number of symbols.
var nSymbols, lastSymbol uint32
for symbol, cl := range codeLengths {
if cl != 0 {
nSymbols++
lastSymbol = uint32(symbol)
}
}
if nSymbols == 0 {
return errInvalidHuffmanTree
}
h.nodes = make([]hNode, 1, 2*nSymbols-1)
// Handle the trivial case.
if nSymbols == 1 {
if len(codeLengths) <= int(lastSymbol) {
return errInvalidHuffmanTree
}
return h.insert(lastSymbol, 0, 0)
}
// Handle the non-trivial case.
codes, err := codeLengthsToCodes(codeLengths)
if err != nil {
return err
}
for symbol, cl := range codeLengths {
if cl > 0 {
if err := h.insert(uint32(symbol), codes[symbol], cl); err != nil {
return err
}
}
}
return nil
}
// buildSimple builds a Huffman tree with 1 or 2 symbols.
func (h *hTree) buildSimple(nSymbols uint32, symbols [2]uint32, alphabetSize uint32) error {
h.nodes = make([]hNode, 1, 2*nSymbols-1)
for i := uint32(0); i < nSymbols; i++ {
if symbols[i] >= alphabetSize {
return errInvalidHuffmanTree
}
if err := h.insert(symbols[i], i, nSymbols-1); err != nil {
return err
}
}
return nil
}
// next returns the next Huffman-encoded symbol from the bit-stream d.
func (h *hTree) next(d *decoder) (uint32, error) {
var n uint32
// Read enough bits so that we can use the look-up table.
if d.nBits < lutSize {
c, err := d.r.ReadByte()
if err != nil {
if err == io.EOF {
// There are no more bytes of data, but we may still be able
// to read the next symbol out of the previously read bits.
goto slowPath
}
return 0, err
}
d.bits |= uint32(c) << d.nBits
d.nBits += 8
}
// Use the look-up table.
n = h.lut[d.bits&lutMask]
if b := n & 0xff; b != 0 {
b--
d.bits >>= b
d.nBits -= b
return n >> 8, nil
}
n >>= 8
d.bits >>= lutSize
d.nBits -= lutSize
slowPath:
for h.nodes[n].children != leafNode {
if d.nBits == 0 {
c, err := d.r.ReadByte()
if err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return 0, err
}
d.bits = uint32(c)
d.nBits = 8
}
n = uint32(h.nodes[n].children) + 1&d.bits
d.bits >>= 1
d.nBits--
}
return h.nodes[n].symbol, nil
}

299
vendor/golang.org/x/image/vp8l/transform.go generated vendored Normal file
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@ -0,0 +1,299 @@
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8l
// This file deals with image transforms, specified in section 3.
// nTiles returns the number of tiles needed to cover size pixels, where each
// tile's side is 1<<bits pixels long.
func nTiles(size int32, bits uint32) int32 {
return (size + 1<<bits - 1) >> bits
}
const (
transformTypePredictor = 0
transformTypeCrossColor = 1
transformTypeSubtractGreen = 2
transformTypeColorIndexing = 3
nTransformTypes = 4
)
// transform holds the parameters for an invertible transform.
type transform struct {
// transformType is the type of the transform.
transformType uint32
// oldWidth is the width of the image before transformation (or
// equivalently, after inverse transformation). The color-indexing
// transform can reduce the width. For example, a 50-pixel-wide
// image that only needs 4 bits (half a byte) per color index can
// be transformed into a 25-pixel-wide image.
oldWidth int32
// bits is the log-2 size of the transform's tiles, for the predictor
// and cross-color transforms. 8>>bits is the number of bits per
// color index, for the color-index transform.
bits uint32
// pix is the tile values, for the predictor and cross-color
// transforms, and the color palette, for the color-index transform.
pix []byte
}
var inverseTransforms = [nTransformTypes]func(*transform, []byte, int32) []byte{
transformTypePredictor: inversePredictor,
transformTypeCrossColor: inverseCrossColor,
transformTypeSubtractGreen: inverseSubtractGreen,
transformTypeColorIndexing: inverseColorIndexing,
}
func inversePredictor(t *transform, pix []byte, h int32) []byte {
if t.oldWidth == 0 || h == 0 {
return pix
}
// The first pixel's predictor is mode 0 (opaque black).
pix[3] += 0xff
p, mask := int32(4), int32(1)<<t.bits-1
for x := int32(1); x < t.oldWidth; x++ {
// The rest of the first row's predictor is mode 1 (L).
pix[p+0] += pix[p-4]
pix[p+1] += pix[p-3]
pix[p+2] += pix[p-2]
pix[p+3] += pix[p-1]
p += 4
}
top, tilesPerRow := 0, nTiles(t.oldWidth, t.bits)
for y := int32(1); y < h; y++ {
// The first column's predictor is mode 2 (T).
pix[p+0] += pix[top+0]
pix[p+1] += pix[top+1]
pix[p+2] += pix[top+2]
pix[p+3] += pix[top+3]
p, top = p+4, top+4
q := 4 * (y >> t.bits) * tilesPerRow
predictorMode := t.pix[q+1] & 0x0f
q += 4
for x := int32(1); x < t.oldWidth; x++ {
if x&mask == 0 {
predictorMode = t.pix[q+1] & 0x0f
q += 4
}
switch predictorMode {
case 0: // Opaque black.
pix[p+3] += 0xff
case 1: // L.
pix[p+0] += pix[p-4]
pix[p+1] += pix[p-3]
pix[p+2] += pix[p-2]
pix[p+3] += pix[p-1]
case 2: // T.
pix[p+0] += pix[top+0]
pix[p+1] += pix[top+1]
pix[p+2] += pix[top+2]
pix[p+3] += pix[top+3]
case 3: // TR.
pix[p+0] += pix[top+4]
pix[p+1] += pix[top+5]
pix[p+2] += pix[top+6]
pix[p+3] += pix[top+7]
case 4: // TL.
pix[p+0] += pix[top-4]
pix[p+1] += pix[top-3]
pix[p+2] += pix[top-2]
pix[p+3] += pix[top-1]
case 5: // Average2(Average2(L, TR), T).
pix[p+0] += avg2(avg2(pix[p-4], pix[top+4]), pix[top+0])
pix[p+1] += avg2(avg2(pix[p-3], pix[top+5]), pix[top+1])
pix[p+2] += avg2(avg2(pix[p-2], pix[top+6]), pix[top+2])
pix[p+3] += avg2(avg2(pix[p-1], pix[top+7]), pix[top+3])
case 6: // Average2(L, TL).
pix[p+0] += avg2(pix[p-4], pix[top-4])
pix[p+1] += avg2(pix[p-3], pix[top-3])
pix[p+2] += avg2(pix[p-2], pix[top-2])
pix[p+3] += avg2(pix[p-1], pix[top-1])
case 7: // Average2(L, T).
pix[p+0] += avg2(pix[p-4], pix[top+0])
pix[p+1] += avg2(pix[p-3], pix[top+1])
pix[p+2] += avg2(pix[p-2], pix[top+2])
pix[p+3] += avg2(pix[p-1], pix[top+3])
case 8: // Average2(TL, T).
pix[p+0] += avg2(pix[top-4], pix[top+0])
pix[p+1] += avg2(pix[top-3], pix[top+1])
pix[p+2] += avg2(pix[top-2], pix[top+2])
pix[p+3] += avg2(pix[top-1], pix[top+3])
case 9: // Average2(T, TR).
pix[p+0] += avg2(pix[top+0], pix[top+4])
pix[p+1] += avg2(pix[top+1], pix[top+5])
pix[p+2] += avg2(pix[top+2], pix[top+6])
pix[p+3] += avg2(pix[top+3], pix[top+7])
case 10: // Average2(Average2(L, TL), Average2(T, TR)).
pix[p+0] += avg2(avg2(pix[p-4], pix[top-4]), avg2(pix[top+0], pix[top+4]))
pix[p+1] += avg2(avg2(pix[p-3], pix[top-3]), avg2(pix[top+1], pix[top+5]))
pix[p+2] += avg2(avg2(pix[p-2], pix[top-2]), avg2(pix[top+2], pix[top+6]))
pix[p+3] += avg2(avg2(pix[p-1], pix[top-1]), avg2(pix[top+3], pix[top+7]))
case 11: // Select(L, T, TL).
l0 := int32(pix[p-4])
l1 := int32(pix[p-3])
l2 := int32(pix[p-2])
l3 := int32(pix[p-1])
c0 := int32(pix[top-4])
c1 := int32(pix[top-3])
c2 := int32(pix[top-2])
c3 := int32(pix[top-1])
t0 := int32(pix[top+0])
t1 := int32(pix[top+1])
t2 := int32(pix[top+2])
t3 := int32(pix[top+3])
l := abs(c0-t0) + abs(c1-t1) + abs(c2-t2) + abs(c3-t3)
t := abs(c0-l0) + abs(c1-l1) + abs(c2-l2) + abs(c3-l3)
if l < t {
pix[p+0] += uint8(l0)
pix[p+1] += uint8(l1)
pix[p+2] += uint8(l2)
pix[p+3] += uint8(l3)
} else {
pix[p+0] += uint8(t0)
pix[p+1] += uint8(t1)
pix[p+2] += uint8(t2)
pix[p+3] += uint8(t3)
}
case 12: // ClampAddSubtractFull(L, T, TL).
pix[p+0] += clampAddSubtractFull(pix[p-4], pix[top+0], pix[top-4])
pix[p+1] += clampAddSubtractFull(pix[p-3], pix[top+1], pix[top-3])
pix[p+2] += clampAddSubtractFull(pix[p-2], pix[top+2], pix[top-2])
pix[p+3] += clampAddSubtractFull(pix[p-1], pix[top+3], pix[top-1])
case 13: // ClampAddSubtractHalf(Average2(L, T), TL).
pix[p+0] += clampAddSubtractHalf(avg2(pix[p-4], pix[top+0]), pix[top-4])
pix[p+1] += clampAddSubtractHalf(avg2(pix[p-3], pix[top+1]), pix[top-3])
pix[p+2] += clampAddSubtractHalf(avg2(pix[p-2], pix[top+2]), pix[top-2])
pix[p+3] += clampAddSubtractHalf(avg2(pix[p-1], pix[top+3]), pix[top-1])
}
p, top = p+4, top+4
}
}
return pix
}
func inverseCrossColor(t *transform, pix []byte, h int32) []byte {
var greenToRed, greenToBlue, redToBlue int32
p, mask, tilesPerRow := int32(0), int32(1)<<t.bits-1, nTiles(t.oldWidth, t.bits)
for y := int32(0); y < h; y++ {
q := 4 * (y >> t.bits) * tilesPerRow
for x := int32(0); x < t.oldWidth; x++ {
if x&mask == 0 {
redToBlue = int32(int8(t.pix[q+0]))
greenToBlue = int32(int8(t.pix[q+1]))
greenToRed = int32(int8(t.pix[q+2]))
q += 4
}
red := pix[p+0]
green := pix[p+1]
blue := pix[p+2]
red += uint8(uint32(greenToRed*int32(int8(green))) >> 5)
blue += uint8(uint32(greenToBlue*int32(int8(green))) >> 5)
blue += uint8(uint32(redToBlue*int32(int8(red))) >> 5)
pix[p+0] = red
pix[p+2] = blue
p += 4
}
}
return pix
}
func inverseSubtractGreen(t *transform, pix []byte, h int32) []byte {
for p := 0; p < len(pix); p += 4 {
green := pix[p+1]
pix[p+0] += green
pix[p+2] += green
}
return pix
}
func inverseColorIndexing(t *transform, pix []byte, h int32) []byte {
if t.bits == 0 {
for p := 0; p < len(pix); p += 4 {
i := 4 * uint32(pix[p+1])
pix[p+0] = t.pix[i+0]
pix[p+1] = t.pix[i+1]
pix[p+2] = t.pix[i+2]
pix[p+3] = t.pix[i+3]
}
return pix
}
vMask, xMask, bitsPerPixel := uint32(0), int32(0), uint32(8>>t.bits)
switch t.bits {
case 1:
vMask, xMask = 0x0f, 0x01
case 2:
vMask, xMask = 0x03, 0x03
case 3:
vMask, xMask = 0x01, 0x07
}
d, p, v, dst := 0, 0, uint32(0), make([]byte, 4*t.oldWidth*h)
for y := int32(0); y < h; y++ {
for x := int32(0); x < t.oldWidth; x++ {
if x&xMask == 0 {
v = uint32(pix[p+1])
p += 4
}
i := 4 * (v & vMask)
dst[d+0] = t.pix[i+0]
dst[d+1] = t.pix[i+1]
dst[d+2] = t.pix[i+2]
dst[d+3] = t.pix[i+3]
d += 4
v >>= bitsPerPixel
}
}
return dst
}
func abs(x int32) int32 {
if x < 0 {
return -x
}
return x
}
func avg2(a, b uint8) uint8 {
return uint8((int32(a) + int32(b)) / 2)
}
func clampAddSubtractFull(a, b, c uint8) uint8 {
x := int32(a) + int32(b) - int32(c)
if x < 0 {
return 0
}
if x > 255 {
return 255
}
return uint8(x)
}
func clampAddSubtractHalf(a, b uint8) uint8 {
x := int32(a) + (int32(a)-int32(b))/2
if x < 0 {
return 0
}
if x > 255 {
return 255
}
return uint8(x)
}

270
vendor/golang.org/x/image/webp/decode.go generated vendored Normal file
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@ -0,0 +1,270 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package webp
import (
"bytes"
"errors"
"image"
"image/color"
"io"
"golang.org/x/image/riff"
"golang.org/x/image/vp8"
"golang.org/x/image/vp8l"
)
var errInvalidFormat = errors.New("webp: invalid format")
var (
fccALPH = riff.FourCC{'A', 'L', 'P', 'H'}
fccVP8 = riff.FourCC{'V', 'P', '8', ' '}
fccVP8L = riff.FourCC{'V', 'P', '8', 'L'}
fccVP8X = riff.FourCC{'V', 'P', '8', 'X'}
fccWEBP = riff.FourCC{'W', 'E', 'B', 'P'}
)
func decode(r io.Reader, configOnly bool) (image.Image, image.Config, error) {
formType, riffReader, err := riff.NewReader(r)
if err != nil {
return nil, image.Config{}, err
}
if formType != fccWEBP {
return nil, image.Config{}, errInvalidFormat
}
var (
alpha []byte
alphaStride int
wantAlpha bool
widthMinusOne uint32
heightMinusOne uint32
buf [10]byte
)
for {
chunkID, chunkLen, chunkData, err := riffReader.Next()
if err == io.EOF {
err = errInvalidFormat
}
if err != nil {
return nil, image.Config{}, err
}
switch chunkID {
case fccALPH:
if !wantAlpha {
return nil, image.Config{}, errInvalidFormat
}
wantAlpha = false
// Read the Pre-processing | Filter | Compression byte.
if _, err := io.ReadFull(chunkData, buf[:1]); err != nil {
if err == io.EOF {
err = errInvalidFormat
}
return nil, image.Config{}, err
}
alpha, alphaStride, err = readAlpha(chunkData, widthMinusOne, heightMinusOne, buf[0]&0x03)
if err != nil {
return nil, image.Config{}, err
}
unfilterAlpha(alpha, alphaStride, (buf[0]>>2)&0x03)
case fccVP8:
if wantAlpha || int32(chunkLen) < 0 {
return nil, image.Config{}, errInvalidFormat
}
d := vp8.NewDecoder()
d.Init(chunkData, int(chunkLen))
fh, err := d.DecodeFrameHeader()
if err != nil {
return nil, image.Config{}, err
}
if configOnly {
return nil, image.Config{
ColorModel: color.YCbCrModel,
Width: fh.Width,
Height: fh.Height,
}, nil
}
m, err := d.DecodeFrame()
if err != nil {
return nil, image.Config{}, err
}
if alpha != nil {
return &image.NYCbCrA{
YCbCr: *m,
A: alpha,
AStride: alphaStride,
}, image.Config{}, nil
}
return m, image.Config{}, nil
case fccVP8L:
if wantAlpha || alpha != nil {
return nil, image.Config{}, errInvalidFormat
}
if configOnly {
c, err := vp8l.DecodeConfig(chunkData)
return nil, c, err
}
m, err := vp8l.Decode(chunkData)
return m, image.Config{}, err
case fccVP8X:
if chunkLen != 10 {
return nil, image.Config{}, errInvalidFormat
}
if _, err := io.ReadFull(chunkData, buf[:10]); err != nil {
return nil, image.Config{}, err
}
const (
animationBit = 1 << 1
xmpMetadataBit = 1 << 2
exifMetadataBit = 1 << 3
alphaBit = 1 << 4
iccProfileBit = 1 << 5
)
if buf[0] != alphaBit {
return nil, image.Config{}, errors.New("webp: non-Alpha VP8X is not implemented")
}
widthMinusOne = uint32(buf[4]) | uint32(buf[5])<<8 | uint32(buf[6])<<16
heightMinusOne = uint32(buf[7]) | uint32(buf[8])<<8 | uint32(buf[9])<<16
if configOnly {
return nil, image.Config{
ColorModel: color.NYCbCrAModel,
Width: int(widthMinusOne) + 1,
Height: int(heightMinusOne) + 1,
}, nil
}
wantAlpha = true
default:
return nil, image.Config{}, errInvalidFormat
}
}
}
func readAlpha(chunkData io.Reader, widthMinusOne, heightMinusOne uint32, compression byte) (
alpha []byte, alphaStride int, err error) {
switch compression {
case 0:
w := int(widthMinusOne) + 1
h := int(heightMinusOne) + 1
alpha = make([]byte, w*h)
if _, err := io.ReadFull(chunkData, alpha); err != nil {
return nil, 0, err
}
return alpha, w, nil
case 1:
// Read the VP8L-compressed alpha values. First, synthesize a 5-byte VP8L header:
// a 1-byte magic number, a 14-bit widthMinusOne, a 14-bit heightMinusOne,
// a 1-bit (ignored, zero) alphaIsUsed and a 3-bit (zero) version.
// TODO(nigeltao): be more efficient than decoding an *image.NRGBA just to
// extract the green values to a separately allocated []byte. Fixing this
// will require changes to the vp8l package's API.
if widthMinusOne > 0x3fff || heightMinusOne > 0x3fff {
return nil, 0, errors.New("webp: invalid format")
}
alphaImage, err := vp8l.Decode(io.MultiReader(
bytes.NewReader([]byte{
0x2f, // VP8L magic number.
uint8(widthMinusOne),
uint8(widthMinusOne>>8) | uint8(heightMinusOne<<6),
uint8(heightMinusOne >> 2),
uint8(heightMinusOne >> 10),
}),
chunkData,
))
if err != nil {
return nil, 0, err
}
// The green values of the inner NRGBA image are the alpha values of the
// outer NYCbCrA image.
pix := alphaImage.(*image.NRGBA).Pix
alpha = make([]byte, len(pix)/4)
for i := range alpha {
alpha[i] = pix[4*i+1]
}
return alpha, int(widthMinusOne) + 1, nil
}
return nil, 0, errInvalidFormat
}
func unfilterAlpha(alpha []byte, alphaStride int, filter byte) {
if len(alpha) == 0 || alphaStride == 0 {
return
}
switch filter {
case 1: // Horizontal filter.
for i := 1; i < alphaStride; i++ {
alpha[i] += alpha[i-1]
}
for i := alphaStride; i < len(alpha); i += alphaStride {
// The first column is equivalent to the vertical filter.
alpha[i] += alpha[i-alphaStride]
for j := 1; j < alphaStride; j++ {
alpha[i+j] += alpha[i+j-1]
}
}
case 2: // Vertical filter.
// The first row is equivalent to the horizontal filter.
for i := 1; i < alphaStride; i++ {
alpha[i] += alpha[i-1]
}
for i := alphaStride; i < len(alpha); i++ {
alpha[i] += alpha[i-alphaStride]
}
case 3: // Gradient filter.
// The first row is equivalent to the horizontal filter.
for i := 1; i < alphaStride; i++ {
alpha[i] += alpha[i-1]
}
for i := alphaStride; i < len(alpha); i += alphaStride {
// The first column is equivalent to the vertical filter.
alpha[i] += alpha[i-alphaStride]
// The interior is predicted on the three top/left pixels.
for j := 1; j < alphaStride; j++ {
c := int(alpha[i+j-alphaStride-1])
b := int(alpha[i+j-alphaStride])
a := int(alpha[i+j-1])
x := a + b - c
if x < 0 {
x = 0
} else if x > 255 {
x = 255
}
alpha[i+j] += uint8(x)
}
}
}
}
// Decode reads a WEBP image from r and returns it as an image.Image.
func Decode(r io.Reader) (image.Image, error) {
m, _, err := decode(r, false)
if err != nil {
return nil, err
}
return m, err
}
// DecodeConfig returns the color model and dimensions of a WEBP image without
// decoding the entire image.
func DecodeConfig(r io.Reader) (image.Config, error) {
_, c, err := decode(r, true)
return c, err
}
func init() {
image.RegisterFormat("webp", "RIFF????WEBPVP8", Decode, DecodeConfig)
}

9
vendor/golang.org/x/image/webp/doc.go generated vendored Normal file
View File

@ -0,0 +1,9 @@
// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package webp implements a decoder for WEBP images.
//
// WEBP is defined at:
// https://developers.google.com/speed/webp/docs/riff_container
package webp // import "golang.org/x/image/webp"

5
vendor/modules.txt vendored
View File

@ -220,6 +220,11 @@ golang.org/x/crypto/ed25519
golang.org/x/crypto/internal/chacha20
golang.org/x/crypto/hkdf
golang.org/x/crypto/ed25519/internal/edwards25519
# golang.org/x/image v0.0.0-20190220214146-31aff87c08e9
golang.org/x/image/webp
golang.org/x/image/riff
golang.org/x/image/vp8
golang.org/x/image/vp8l
# golang.org/x/net v0.0.0-20190110200230-915654e7eabc
golang.org/x/net/websocket
# golang.org/x/sys v0.0.0-20190129075346-302c3dd5f1cc