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1a3f26fb5c* media: add webp support Signed-off-by: Sigrid Solveig Haflínudóttir <sigrid@ftrv.se> * bump exif-terminator to v0.5.0 Signed-off-by: Sigrid Solveig Haflínudóttir <sigrid@ftrv.se> Signed-off-by: Sigrid Solveig Haflínudóttir <sigrid@ftrv.se>
553 lines
13 KiB
Go
553 lines
13 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package vp8
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// This file implements the predicition functions, as specified in chapter 12.
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//
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// For each macroblock (of 1x16x16 luma and 2x8x8 chroma coefficients), the
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// luma values are either predicted as one large 16x16 region or 16 separate
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// 4x4 regions. The chroma values are always predicted as one 8x8 region.
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//
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// For 4x4 regions, the target block's predicted values (Xs) are a function of
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// its previously-decoded top and left border values, as well as a number of
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// pixels from the top-right:
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//
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// a b c d e f g h
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// p X X X X
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// q X X X X
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// r X X X X
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// s X X X X
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//
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// The predictor modes are:
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// - DC: all Xs = (b + c + d + e + p + q + r + s + 4) / 8.
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// - TM: the first X = (b + p - a), the second X = (c + p - a), and so on.
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// - VE: each X = the weighted average of its column's top value and that
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// value's neighbors, i.e. averages of abc, bcd, cde or def.
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// - HE: similar to VE except rows instead of columns, and the final row is
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// an average of r, s and s.
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// - RD, VR, LD, VL, HD, HU: these diagonal modes ("Right Down", "Vertical
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// Right", etc) are more complicated and are described in section 12.3.
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// All Xs are clipped to the range [0, 255].
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//
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// For 8x8 and 16x16 regions, the target block's predicted values are a
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// function of the top and left border values without the top-right overhang,
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// i.e. without the 8x8 or 16x16 equivalent of f, g and h. Furthermore:
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// - There are no diagonal predictor modes, only DC, TM, VE and HE.
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// - The DC mode has variants for macroblocks in the top row and/or left
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// column, i.e. for macroblocks with mby == 0 || mbx == 0.
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// - The VE and HE modes take only the column top or row left values; they do
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// not smooth that top/left value with its neighbors.
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// nPred is the number of predictor modes, not including the Top/Left versions
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// of the DC predictor mode.
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const nPred = 10
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const (
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predDC = iota
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predTM
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predVE
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predHE
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predRD
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predVR
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predLD
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predVL
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predHD
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predHU
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predDCTop
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predDCLeft
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predDCTopLeft
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)
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func checkTopLeftPred(mbx, mby int, p uint8) uint8 {
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if p != predDC {
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return p
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}
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if mbx == 0 {
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if mby == 0 {
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return predDCTopLeft
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}
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return predDCLeft
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}
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if mby == 0 {
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return predDCTop
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}
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return predDC
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}
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var predFunc4 = [...]func(*Decoder, int, int){
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predFunc4DC,
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predFunc4TM,
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predFunc4VE,
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predFunc4HE,
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predFunc4RD,
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predFunc4VR,
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predFunc4LD,
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predFunc4VL,
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predFunc4HD,
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predFunc4HU,
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nil,
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nil,
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nil,
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}
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var predFunc8 = [...]func(*Decoder, int, int){
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predFunc8DC,
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predFunc8TM,
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predFunc8VE,
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predFunc8HE,
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nil,
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nil,
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nil,
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nil,
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nil,
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nil,
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predFunc8DCTop,
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predFunc8DCLeft,
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predFunc8DCTopLeft,
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}
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var predFunc16 = [...]func(*Decoder, int, int){
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predFunc16DC,
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predFunc16TM,
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predFunc16VE,
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predFunc16HE,
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nil,
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nil,
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nil,
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nil,
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nil,
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nil,
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predFunc16DCTop,
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predFunc16DCLeft,
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predFunc16DCTopLeft,
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}
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func predFunc4DC(z *Decoder, y, x int) {
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sum := uint32(4)
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for i := 0; i < 4; i++ {
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sum += uint32(z.ybr[y-1][x+i])
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}
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for j := 0; j < 4; j++ {
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sum += uint32(z.ybr[y+j][x-1])
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}
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avg := uint8(sum / 8)
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for j := 0; j < 4; j++ {
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for i := 0; i < 4; i++ {
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z.ybr[y+j][x+i] = avg
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}
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}
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}
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func predFunc4TM(z *Decoder, y, x int) {
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delta0 := -int32(z.ybr[y-1][x-1])
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for j := 0; j < 4; j++ {
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delta1 := delta0 + int32(z.ybr[y+j][x-1])
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for i := 0; i < 4; i++ {
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delta2 := delta1 + int32(z.ybr[y-1][x+i])
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z.ybr[y+j][x+i] = uint8(clip(delta2, 0, 255))
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}
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}
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}
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func predFunc4VE(z *Decoder, y, x int) {
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a := int32(z.ybr[y-1][x-1])
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b := int32(z.ybr[y-1][x+0])
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c := int32(z.ybr[y-1][x+1])
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d := int32(z.ybr[y-1][x+2])
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e := int32(z.ybr[y-1][x+3])
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f := int32(z.ybr[y-1][x+4])
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abc := uint8((a + 2*b + c + 2) / 4)
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bcd := uint8((b + 2*c + d + 2) / 4)
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cde := uint8((c + 2*d + e + 2) / 4)
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def := uint8((d + 2*e + f + 2) / 4)
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for j := 0; j < 4; j++ {
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z.ybr[y+j][x+0] = abc
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z.ybr[y+j][x+1] = bcd
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z.ybr[y+j][x+2] = cde
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z.ybr[y+j][x+3] = def
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}
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}
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func predFunc4HE(z *Decoder, y, x int) {
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s := int32(z.ybr[y+3][x-1])
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r := int32(z.ybr[y+2][x-1])
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q := int32(z.ybr[y+1][x-1])
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p := int32(z.ybr[y+0][x-1])
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a := int32(z.ybr[y-1][x-1])
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ssr := uint8((s + 2*s + r + 2) / 4)
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srq := uint8((s + 2*r + q + 2) / 4)
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rqp := uint8((r + 2*q + p + 2) / 4)
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apq := uint8((a + 2*p + q + 2) / 4)
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for i := 0; i < 4; i++ {
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z.ybr[y+0][x+i] = apq
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z.ybr[y+1][x+i] = rqp
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z.ybr[y+2][x+i] = srq
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z.ybr[y+3][x+i] = ssr
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}
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}
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func predFunc4RD(z *Decoder, y, x int) {
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s := int32(z.ybr[y+3][x-1])
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r := int32(z.ybr[y+2][x-1])
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q := int32(z.ybr[y+1][x-1])
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p := int32(z.ybr[y+0][x-1])
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a := int32(z.ybr[y-1][x-1])
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b := int32(z.ybr[y-1][x+0])
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c := int32(z.ybr[y-1][x+1])
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d := int32(z.ybr[y-1][x+2])
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e := int32(z.ybr[y-1][x+3])
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srq := uint8((s + 2*r + q + 2) / 4)
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rqp := uint8((r + 2*q + p + 2) / 4)
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qpa := uint8((q + 2*p + a + 2) / 4)
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pab := uint8((p + 2*a + b + 2) / 4)
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abc := uint8((a + 2*b + c + 2) / 4)
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bcd := uint8((b + 2*c + d + 2) / 4)
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cde := uint8((c + 2*d + e + 2) / 4)
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z.ybr[y+0][x+0] = pab
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z.ybr[y+0][x+1] = abc
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z.ybr[y+0][x+2] = bcd
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z.ybr[y+0][x+3] = cde
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z.ybr[y+1][x+0] = qpa
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z.ybr[y+1][x+1] = pab
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z.ybr[y+1][x+2] = abc
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z.ybr[y+1][x+3] = bcd
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z.ybr[y+2][x+0] = rqp
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z.ybr[y+2][x+1] = qpa
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z.ybr[y+2][x+2] = pab
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z.ybr[y+2][x+3] = abc
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z.ybr[y+3][x+0] = srq
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z.ybr[y+3][x+1] = rqp
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z.ybr[y+3][x+2] = qpa
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z.ybr[y+3][x+3] = pab
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}
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func predFunc4VR(z *Decoder, y, x int) {
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r := int32(z.ybr[y+2][x-1])
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q := int32(z.ybr[y+1][x-1])
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p := int32(z.ybr[y+0][x-1])
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a := int32(z.ybr[y-1][x-1])
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b := int32(z.ybr[y-1][x+0])
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c := int32(z.ybr[y-1][x+1])
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d := int32(z.ybr[y-1][x+2])
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e := int32(z.ybr[y-1][x+3])
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ab := uint8((a + b + 1) / 2)
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bc := uint8((b + c + 1) / 2)
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cd := uint8((c + d + 1) / 2)
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de := uint8((d + e + 1) / 2)
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rqp := uint8((r + 2*q + p + 2) / 4)
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qpa := uint8((q + 2*p + a + 2) / 4)
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pab := uint8((p + 2*a + b + 2) / 4)
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abc := uint8((a + 2*b + c + 2) / 4)
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bcd := uint8((b + 2*c + d + 2) / 4)
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cde := uint8((c + 2*d + e + 2) / 4)
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z.ybr[y+0][x+0] = ab
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z.ybr[y+0][x+1] = bc
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z.ybr[y+0][x+2] = cd
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z.ybr[y+0][x+3] = de
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z.ybr[y+1][x+0] = pab
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z.ybr[y+1][x+1] = abc
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z.ybr[y+1][x+2] = bcd
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z.ybr[y+1][x+3] = cde
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z.ybr[y+2][x+0] = qpa
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z.ybr[y+2][x+1] = ab
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z.ybr[y+2][x+2] = bc
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z.ybr[y+2][x+3] = cd
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z.ybr[y+3][x+0] = rqp
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z.ybr[y+3][x+1] = pab
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z.ybr[y+3][x+2] = abc
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z.ybr[y+3][x+3] = bcd
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}
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func predFunc4LD(z *Decoder, y, x int) {
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a := int32(z.ybr[y-1][x+0])
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b := int32(z.ybr[y-1][x+1])
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c := int32(z.ybr[y-1][x+2])
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d := int32(z.ybr[y-1][x+3])
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e := int32(z.ybr[y-1][x+4])
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f := int32(z.ybr[y-1][x+5])
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g := int32(z.ybr[y-1][x+6])
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h := int32(z.ybr[y-1][x+7])
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abc := uint8((a + 2*b + c + 2) / 4)
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bcd := uint8((b + 2*c + d + 2) / 4)
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cde := uint8((c + 2*d + e + 2) / 4)
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def := uint8((d + 2*e + f + 2) / 4)
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efg := uint8((e + 2*f + g + 2) / 4)
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fgh := uint8((f + 2*g + h + 2) / 4)
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ghh := uint8((g + 2*h + h + 2) / 4)
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z.ybr[y+0][x+0] = abc
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z.ybr[y+0][x+1] = bcd
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z.ybr[y+0][x+2] = cde
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z.ybr[y+0][x+3] = def
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z.ybr[y+1][x+0] = bcd
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z.ybr[y+1][x+1] = cde
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z.ybr[y+1][x+2] = def
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z.ybr[y+1][x+3] = efg
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z.ybr[y+2][x+0] = cde
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z.ybr[y+2][x+1] = def
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z.ybr[y+2][x+2] = efg
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z.ybr[y+2][x+3] = fgh
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z.ybr[y+3][x+0] = def
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z.ybr[y+3][x+1] = efg
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z.ybr[y+3][x+2] = fgh
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z.ybr[y+3][x+3] = ghh
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}
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func predFunc4VL(z *Decoder, y, x int) {
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a := int32(z.ybr[y-1][x+0])
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b := int32(z.ybr[y-1][x+1])
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c := int32(z.ybr[y-1][x+2])
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d := int32(z.ybr[y-1][x+3])
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e := int32(z.ybr[y-1][x+4])
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f := int32(z.ybr[y-1][x+5])
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g := int32(z.ybr[y-1][x+6])
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h := int32(z.ybr[y-1][x+7])
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ab := uint8((a + b + 1) / 2)
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bc := uint8((b + c + 1) / 2)
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cd := uint8((c + d + 1) / 2)
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de := uint8((d + e + 1) / 2)
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abc := uint8((a + 2*b + c + 2) / 4)
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bcd := uint8((b + 2*c + d + 2) / 4)
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cde := uint8((c + 2*d + e + 2) / 4)
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def := uint8((d + 2*e + f + 2) / 4)
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efg := uint8((e + 2*f + g + 2) / 4)
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fgh := uint8((f + 2*g + h + 2) / 4)
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z.ybr[y+0][x+0] = ab
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z.ybr[y+0][x+1] = bc
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z.ybr[y+0][x+2] = cd
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z.ybr[y+0][x+3] = de
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z.ybr[y+1][x+0] = abc
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z.ybr[y+1][x+1] = bcd
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z.ybr[y+1][x+2] = cde
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z.ybr[y+1][x+3] = def
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z.ybr[y+2][x+0] = bc
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z.ybr[y+2][x+1] = cd
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z.ybr[y+2][x+2] = de
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z.ybr[y+2][x+3] = efg
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z.ybr[y+3][x+0] = bcd
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z.ybr[y+3][x+1] = cde
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z.ybr[y+3][x+2] = def
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z.ybr[y+3][x+3] = fgh
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}
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func predFunc4HD(z *Decoder, y, x int) {
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s := int32(z.ybr[y+3][x-1])
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r := int32(z.ybr[y+2][x-1])
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q := int32(z.ybr[y+1][x-1])
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p := int32(z.ybr[y+0][x-1])
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a := int32(z.ybr[y-1][x-1])
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b := int32(z.ybr[y-1][x+0])
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c := int32(z.ybr[y-1][x+1])
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d := int32(z.ybr[y-1][x+2])
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sr := uint8((s + r + 1) / 2)
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rq := uint8((r + q + 1) / 2)
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qp := uint8((q + p + 1) / 2)
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pa := uint8((p + a + 1) / 2)
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srq := uint8((s + 2*r + q + 2) / 4)
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rqp := uint8((r + 2*q + p + 2) / 4)
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qpa := uint8((q + 2*p + a + 2) / 4)
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pab := uint8((p + 2*a + b + 2) / 4)
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abc := uint8((a + 2*b + c + 2) / 4)
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bcd := uint8((b + 2*c + d + 2) / 4)
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z.ybr[y+0][x+0] = pa
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z.ybr[y+0][x+1] = pab
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z.ybr[y+0][x+2] = abc
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z.ybr[y+0][x+3] = bcd
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z.ybr[y+1][x+0] = qp
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z.ybr[y+1][x+1] = qpa
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z.ybr[y+1][x+2] = pa
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z.ybr[y+1][x+3] = pab
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z.ybr[y+2][x+0] = rq
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z.ybr[y+2][x+1] = rqp
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z.ybr[y+2][x+2] = qp
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z.ybr[y+2][x+3] = qpa
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z.ybr[y+3][x+0] = sr
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z.ybr[y+3][x+1] = srq
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z.ybr[y+3][x+2] = rq
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z.ybr[y+3][x+3] = rqp
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}
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func predFunc4HU(z *Decoder, y, x int) {
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s := int32(z.ybr[y+3][x-1])
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r := int32(z.ybr[y+2][x-1])
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q := int32(z.ybr[y+1][x-1])
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p := int32(z.ybr[y+0][x-1])
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pq := uint8((p + q + 1) / 2)
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qr := uint8((q + r + 1) / 2)
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rs := uint8((r + s + 1) / 2)
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pqr := uint8((p + 2*q + r + 2) / 4)
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qrs := uint8((q + 2*r + s + 2) / 4)
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rss := uint8((r + 2*s + s + 2) / 4)
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sss := uint8(s)
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z.ybr[y+0][x+0] = pq
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z.ybr[y+0][x+1] = pqr
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z.ybr[y+0][x+2] = qr
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z.ybr[y+0][x+3] = qrs
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z.ybr[y+1][x+0] = qr
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z.ybr[y+1][x+1] = qrs
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z.ybr[y+1][x+2] = rs
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z.ybr[y+1][x+3] = rss
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z.ybr[y+2][x+0] = rs
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z.ybr[y+2][x+1] = rss
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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
|
|
}
|
|
}
|
|
}
|