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Diffstat (limited to 'vendor/golang.org/x/image/vp8/predfunc.go')
| -rw-r--r-- | vendor/golang.org/x/image/vp8/predfunc.go | 553 |
1 files changed, 553 insertions, 0 deletions
diff --git a/vendor/golang.org/x/image/vp8/predfunc.go b/vendor/golang.org/x/image/vp8/predfunc.go new file mode 100644 index 00000000..f8999582 --- /dev/null +++ b/vendor/golang.org/x/image/vp8/predfunc.go @@ -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 + } + } +} |