libbpg/x265/source/encoder/weightPrediction.cpp
2015-10-27 11:46:00 +01:00

536 lines
20 KiB
C++

/*****************************************************************************
* Copyright (C) 2013 x265 project
*
* Author: Shazeb Nawaz Khan <shazeb@multicorewareinc.com>
* Steve Borho <steve@borho.org>
* Kavitha Sampas <kavitha@multicorewareinc.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111, USA.
*
* This program is also available under a commercial proprietary license.
* For more information, contact us at license @ x265.com.
*****************************************************************************/
#include "common.h"
#include "frame.h"
#include "picyuv.h"
#include "lowres.h"
#include "slice.h"
#include "mv.h"
#include "bitstream.h"
using namespace X265_NS;
namespace {
struct Cache
{
const int * intraCost;
int numPredDir;
int csp;
int hshift;
int vshift;
int lowresWidthInCU;
int lowresHeightInCU;
};
int sliceHeaderCost(WeightParam *w, int lambda, int bChroma)
{
/* 4 times higher, because chroma is analyzed at full resolution. */
if (bChroma)
lambda *= 4;
int denomCost = bs_size_ue(w[0].log2WeightDenom) * (2 - bChroma);
return lambda * (10 + denomCost + 2 * (bs_size_se(w[0].inputWeight) + bs_size_se(w[0].inputOffset)));
}
/* make a motion compensated copy of lowres ref into mcout with the same stride.
* The borders of mcout are not extended */
void mcLuma(pixel* mcout, Lowres& ref, const MV * mvs)
{
intptr_t stride = ref.lumaStride;
const int mvshift = 1 << 2;
const int cuSize = 8;
MV mvmin, mvmax;
int cu = 0;
for (int y = 0; y < ref.lines; y += cuSize)
{
intptr_t pixoff = y * stride;
mvmin.y = (int16_t)((-y - 8) * mvshift);
mvmax.y = (int16_t)((ref.lines - y - 1 + 8) * mvshift);
for (int x = 0; x < ref.width; x += cuSize, pixoff += cuSize, cu++)
{
ALIGN_VAR_16(pixel, buf8x8[8 * 8]);
intptr_t bstride = 8;
mvmin.x = (int16_t)((-x - 8) * mvshift);
mvmax.x = (int16_t)((ref.width - x - 1 + 8) * mvshift);
/* clip MV to available pixels */
MV mv = mvs[cu];
mv = mv.clipped(mvmin, mvmax);
pixel *tmp = ref.lowresMC(pixoff, mv, buf8x8, bstride);
primitives.cu[BLOCK_8x8].copy_pp(mcout + pixoff, stride, tmp, bstride);
}
}
}
/* use lowres MVs from lookahead to generate a motion compensated chroma plane.
* if a block had cheaper lowres cost as intra, we treat it as MV 0 */
void mcChroma(pixel * mcout,
pixel * src,
intptr_t stride,
const MV * mvs,
const Cache& cache,
int height,
int width)
{
/* the motion vectors correspond to 8x8 lowres luma blocks, or 16x16 fullres
* luma blocks. We have to adapt block size to chroma csp */
int csp = cache.csp;
int bw = 16 >> cache.hshift;
int bh = 16 >> cache.vshift;
const int mvshift = 1 << 2;
MV mvmin, mvmax;
for (int y = 0; y < height; y += bh)
{
/* note: lowres block count per row might be different from chroma block
* count per row because of rounding issues, so be very careful with indexing
* into the lowres structures */
int cu = y * cache.lowresWidthInCU;
intptr_t pixoff = y * stride;
mvmin.y = (int16_t)((-y - 8) * mvshift);
mvmax.y = (int16_t)((height - y - 1 + 8) * mvshift);
for (int x = 0; x < width; x += bw, cu++, pixoff += bw)
{
if (x < cache.lowresWidthInCU && y < cache.lowresHeightInCU)
{
MV mv = mvs[cu]; // lowres MV
mv <<= 1; // fullres MV
mv.x >>= cache.hshift;
mv.y >>= cache.vshift;
/* clip MV to available pixels */
mvmin.x = (int16_t)((-x - 8) * mvshift);
mvmax.x = (int16_t)((width - x - 1 + 8) * mvshift);
mv = mv.clipped(mvmin, mvmax);
intptr_t fpeloffset = (mv.y >> 2) * stride + (mv.x >> 2);
pixel *temp = src + pixoff + fpeloffset;
int xFrac = mv.x & 0x7;
int yFrac = mv.y & 0x7;
if ((yFrac | xFrac) == 0)
{
primitives.chroma[csp].pu[LUMA_16x16].copy_pp(mcout + pixoff, stride, temp, stride);
}
else if (yFrac == 0)
{
primitives.chroma[csp].pu[LUMA_16x16].filter_hpp(temp, stride, mcout + pixoff, stride, xFrac);
}
else if (xFrac == 0)
{
primitives.chroma[csp].pu[LUMA_16x16].filter_vpp(temp, stride, mcout + pixoff, stride, yFrac);
}
else
{
ALIGN_VAR_16(int16_t, imm[16 * (16 + NTAPS_CHROMA)]);
primitives.chroma[csp].pu[LUMA_16x16].filter_hps(temp, stride, imm, bw, xFrac, 1);
primitives.chroma[csp].pu[LUMA_16x16].filter_vsp(imm + ((NTAPS_CHROMA >> 1) - 1) * bw, bw, mcout + pixoff, stride, yFrac);
}
}
else
{
primitives.chroma[csp].pu[LUMA_16x16].copy_pp(mcout + pixoff, stride, src + pixoff, stride);
}
}
}
}
/* Measure sum of 8x8 satd costs between source frame and reference
* frame (potentially weighted, potentially motion compensated). We
* always use source images for this analysis since reference recon
* pixels have unreliable availability */
uint32_t weightCost(pixel * fenc,
pixel * ref,
pixel * weightTemp,
intptr_t stride,
const Cache & cache,
int width,
int height,
WeightParam * w,
bool bLuma)
{
if (w)
{
/* make a weighted copy of the reference plane */
int offset = w->inputOffset << (X265_DEPTH - 8);
int weight = w->inputWeight;
int denom = w->log2WeightDenom;
int round = denom ? 1 << (denom - 1) : 0;
int correction = IF_INTERNAL_PREC - X265_DEPTH; /* intermediate interpolation depth */
int pwidth = ((width + 15) >> 4) << 4;
primitives.weight_pp(ref, weightTemp, stride, pwidth, height,
weight, round << correction, denom + correction, offset);
ref = weightTemp;
}
uint32_t cost = 0;
pixel *f = fenc, *r = ref;
if (bLuma)
{
int cu = 0;
for (int y = 0; y < height; y += 8, r += 8 * stride, f += 8 * stride)
{
for (int x = 0; x < width; x += 8, cu++)
{
int cmp = primitives.pu[LUMA_8x8].satd(r + x, stride, f + x, stride);
cost += X265_MIN(cmp, cache.intraCost[cu]);
}
}
}
else if (cache.csp == X265_CSP_I444)
for (int y = 0; y < height; y += 16, r += 16 * stride, f += 16 * stride)
for (int x = 0; x < width; x += 16)
cost += primitives.pu[LUMA_16x16].satd(r + x, stride, f + x, stride);
else
for (int y = 0; y < height; y += 8, r += 8 * stride, f += 8 * stride)
for (int x = 0; x < width; x += 8)
cost += primitives.pu[LUMA_8x8].satd(r + x, stride, f + x, stride);
return cost;
}
}
namespace X265_NS {
void weightAnalyse(Slice& slice, Frame& frame, x265_param& param)
{
WeightParam wp[2][MAX_NUM_REF][3];
PicYuv *fencPic = frame.m_fencPic;
Lowres& fenc = frame.m_lowres;
Cache cache;
memset(&cache, 0, sizeof(cache));
cache.intraCost = fenc.intraCost;
cache.numPredDir = slice.isInterP() ? 1 : 2;
cache.lowresWidthInCU = fenc.width >> 3;
cache.lowresHeightInCU = fenc.lines >> 3;
cache.csp = fencPic->m_picCsp;
cache.hshift = CHROMA_H_SHIFT(cache.csp);
cache.vshift = CHROMA_V_SHIFT(cache.csp);
/* Use single allocation for motion compensated ref and weight buffers */
pixel *mcbuf = X265_MALLOC(pixel, 2 * fencPic->m_stride * fencPic->m_picHeight);
if (!mcbuf)
{
slice.disableWeights();
return;
}
pixel *weightTemp = mcbuf + fencPic->m_stride * fencPic->m_picHeight;
int lambda = (int)x265_lambda_tab[X265_LOOKAHEAD_QP];
int curPoc = slice.m_poc;
const float epsilon = 1.f / 128.f;
int chromaDenom, lumaDenom, denom;
chromaDenom = lumaDenom = 7;
int numpixels[3];
int w16 = ((fencPic->m_picWidth + 15) >> 4) << 4;
int h16 = ((fencPic->m_picHeight + 15) >> 4) << 4;
numpixels[0] = w16 * h16;
numpixels[1] = numpixels[2] = numpixels[0] >> (cache.hshift + cache.vshift);
for (int list = 0; list < cache.numPredDir; list++)
{
WeightParam *weights = wp[list][0];
Frame *refFrame = slice.m_refFrameList[list][0];
Lowres& refLowres = refFrame->m_lowres;
int diffPoc = abs(curPoc - refFrame->m_poc);
/* prepare estimates */
float guessScale[3], fencMean[3], refMean[3];
for (int plane = 0; plane < 3; plane++)
{
SET_WEIGHT(weights[plane], false, 1, 0, 0);
uint64_t fencVar = fenc.wp_ssd[plane] + !refLowres.wp_ssd[plane];
uint64_t refVar = refLowres.wp_ssd[plane] + !refLowres.wp_ssd[plane];
guessScale[plane] = sqrt((float)fencVar / refVar);
fencMean[plane] = (float)fenc.wp_sum[plane] / (numpixels[plane]) / (1 << (X265_DEPTH - 8));
refMean[plane] = (float)refLowres.wp_sum[plane] / (numpixels[plane]) / (1 << (X265_DEPTH - 8));
}
/* make sure both our scale factors fit */
while (!list && chromaDenom > 0)
{
float thresh = 127.f / (1 << chromaDenom);
if (guessScale[1] < thresh && guessScale[2] < thresh)
break;
chromaDenom--;
}
SET_WEIGHT(weights[1], false, 1 << chromaDenom, chromaDenom, 0);
SET_WEIGHT(weights[2], false, 1 << chromaDenom, chromaDenom, 0);
MV *mvs = NULL;
for (int plane = 0; plane < 3; plane++)
{
denom = plane ? chromaDenom : lumaDenom;
if (plane && !weights[0].bPresentFlag)
break;
/* Early termination */
x265_emms();
if (fabsf(refMean[plane] - fencMean[plane]) < 0.5f && fabsf(1.f - guessScale[plane]) < epsilon)
{
SET_WEIGHT(weights[plane], 0, 1 << denom, denom, 0);
continue;
}
if (plane)
{
int scale = x265_clip3(0, 255, (int)(guessScale[plane] * (1 << denom) + 0.5f));
if (scale > 127)
continue;
weights[plane].inputWeight = scale;
}
else
{
weights[plane].setFromWeightAndOffset((int)(guessScale[plane] * (1 << denom) + 0.5f), 0, denom, !list);
}
int mindenom = weights[plane].log2WeightDenom;
int minscale = weights[plane].inputWeight;
int minoff = 0;
if (!plane && diffPoc <= param.bframes + 1)
{
mvs = fenc.lowresMvs[list][diffPoc - 1];
/* test whether this motion search was performed by lookahead */
if (mvs[0].x != 0x7FFF)
{
/* reference chroma planes must be extended prior to being
* used as motion compensation sources */
if (!refFrame->m_bChromaExtended)
{
refFrame->m_bChromaExtended = true;
PicYuv *refPic = refFrame->m_fencPic;
int width = refPic->m_picWidth >> cache.hshift;
int height = refPic->m_picHeight >> cache.vshift;
extendPicBorder(refPic->m_picOrg[1], refPic->m_strideC, width, height, refPic->m_chromaMarginX, refPic->m_chromaMarginY);
extendPicBorder(refPic->m_picOrg[2], refPic->m_strideC, width, height, refPic->m_chromaMarginX, refPic->m_chromaMarginY);
}
}
else
mvs = 0;
}
/* prepare inputs to weight analysis */
pixel *orig;
pixel *fref;
intptr_t stride;
int width, height;
switch (plane)
{
case 0:
orig = fenc.lowresPlane[0];
stride = fenc.lumaStride;
width = fenc.width;
height = fenc.lines;
fref = refLowres.lowresPlane[0];
if (mvs)
{
mcLuma(mcbuf, refLowres, mvs);
fref = mcbuf;
}
break;
case 1:
orig = fencPic->m_picOrg[1];
stride = fencPic->m_strideC;
fref = refFrame->m_fencPic->m_picOrg[1];
/* Clamp the chroma dimensions to the nearest multiple of
* 8x8 blocks (or 16x16 for 4:4:4) since mcChroma uses lowres
* blocks and weightCost measures 8x8 blocks. This
* potentially ignores some edge pixels, but simplifies the
* logic and prevents reading uninitialized pixels. Lowres
* planes are border extended and require no clamping. */
width = ((fencPic->m_picWidth >> 4) << 4) >> cache.hshift;
height = ((fencPic->m_picHeight >> 4) << 4) >> cache.vshift;
if (mvs)
{
mcChroma(mcbuf, fref, stride, mvs, cache, height, width);
fref = mcbuf;
}
break;
case 2:
orig = fencPic->m_picOrg[2];
stride = fencPic->m_strideC;
fref = refFrame->m_fencPic->m_picOrg[2];
width = ((fencPic->m_picWidth >> 4) << 4) >> cache.hshift;
height = ((fencPic->m_picHeight >> 4) << 4) >> cache.vshift;
if (mvs)
{
mcChroma(mcbuf, fref, stride, mvs, cache, height, width);
fref = mcbuf;
}
break;
default:
slice.disableWeights();
X265_FREE(mcbuf);
return;
}
uint32_t origscore = weightCost(orig, fref, weightTemp, stride, cache, width, height, NULL, !plane);
if (!origscore)
{
SET_WEIGHT(weights[plane], 0, 1 << denom, denom, 0);
continue;
}
uint32_t minscore = origscore;
bool bFound = false;
/* x264 uses a table lookup here, selecting search range based on preset */
static const int scaleDist = 4;
static const int offsetDist = 2;
int startScale = x265_clip3(0, 127, minscale - scaleDist);
int endScale = x265_clip3(0, 127, minscale + scaleDist);
for (int scale = startScale; scale <= endScale; scale++)
{
int deltaWeight = scale - (1 << mindenom);
if (deltaWeight > 127 || deltaWeight <= -128)
continue;
x265_emms();
int curScale = scale;
int curOffset = (int)(fencMean[plane] - refMean[plane] * curScale / (1 << mindenom) + 0.5f);
if (curOffset < -128 || curOffset > 127)
{
/* Rescale considering the constraints on curOffset. We do it in this order
* because scale has a much wider range than offset (because of denom), so
* it should almost never need to be clamped. */
curOffset = x265_clip3(-128, 127, curOffset);
curScale = (int)((1 << mindenom) * (fencMean[plane] - curOffset) / refMean[plane] + 0.5f);
curScale = x265_clip3(0, 127, curScale);
}
int startOffset = x265_clip3(-128, 127, curOffset - offsetDist);
int endOffset = x265_clip3(-128, 127, curOffset + offsetDist);
for (int off = startOffset; off <= endOffset; off++)
{
WeightParam wsp;
SET_WEIGHT(wsp, true, curScale, mindenom, off);
uint32_t s = weightCost(orig, fref, weightTemp, stride, cache, width, height, &wsp, !plane) +
sliceHeaderCost(&wsp, lambda, !!plane);
COPY4_IF_LT(minscore, s, minscale, curScale, minoff, off, bFound, true);
/* Don't check any more offsets if the previous one had a lower cost than the current one */
if (minoff == startOffset && off != startOffset)
break;
}
}
/* Use a smaller luma denominator if possible */
if (!(plane || list))
{
while (mindenom > 0 && !(minscale & 1))
{
mindenom--;
minscale >>= 1;
}
}
if (!bFound || (minscale == (1 << mindenom) && minoff == 0) || (float)minscore / origscore > 0.998f)
{
SET_WEIGHT(weights[plane], false, 1 << denom, denom, 0);
}
else
{
SET_WEIGHT(weights[plane], true, minscale, mindenom, minoff);
}
}
if (weights[0].bPresentFlag)
{
// Make sure both chroma channels match
if (weights[1].bPresentFlag != weights[2].bPresentFlag)
{
if (weights[1].bPresentFlag)
weights[2] = weights[1];
else
weights[1] = weights[2];
}
}
lumaDenom = weights[0].log2WeightDenom;
chromaDenom = weights[1].log2WeightDenom;
/* reset weight states */
for (int ref = 1; ref < slice.m_numRefIdx[list]; ref++)
{
SET_WEIGHT(wp[list][ref][0], false, 1 << lumaDenom, lumaDenom, 0);
SET_WEIGHT(wp[list][ref][1], false, 1 << chromaDenom, chromaDenom, 0);
SET_WEIGHT(wp[list][ref][2], false, 1 << chromaDenom, chromaDenom, 0);
}
}
X265_FREE(mcbuf);
memcpy(slice.m_weightPredTable, wp, sizeof(WeightParam) * 2 * MAX_NUM_REF * 3);
if (param.logLevel >= X265_LOG_FULL)
{
char buf[1024];
int p = 0;
bool bWeighted = false;
p = sprintf(buf, "poc: %d weights:", slice.m_poc);
int numPredDir = slice.isInterP() ? 1 : 2;
for (int list = 0; list < numPredDir; list++)
{
WeightParam* w = &wp[list][0][0];
if (w[0].bPresentFlag || w[1].bPresentFlag || w[2].bPresentFlag)
{
bWeighted = true;
p += sprintf(buf + p, " [L%d:R0 ", list);
if (w[0].bPresentFlag)
p += sprintf(buf + p, "Y{%d/%d%+d}", w[0].inputWeight, 1 << w[0].log2WeightDenom, w[0].inputOffset);
if (w[1].bPresentFlag)
p += sprintf(buf + p, "U{%d/%d%+d}", w[1].inputWeight, 1 << w[1].log2WeightDenom, w[1].inputOffset);
if (w[2].bPresentFlag)
p += sprintf(buf + p, "V{%d/%d%+d}", w[2].inputWeight, 1 << w[2].log2WeightDenom, w[2].inputOffset);
p += sprintf(buf + p, "]");
}
}
if (bWeighted)
{
if (p < 80) // pad with spaces to ensure progress line overwritten
sprintf(buf + p, "%*s", 80 - p, " ");
x265_log(&param, X265_LOG_FULL, "%s\n", buf);
}
}
}
}