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sse2 version of CollectHistogram()

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~3% faster encoding.

Patch by Christian Duvivier (cduvivier at google dot com)

Change-Id: I8c11d63d0cffb35e145fe0ea74cb66a53f4950d9
This commit is contained in:
Pascal Massimino
2011-04-28 17:00:22 -07:00
parent c1c728d617
commit d757523889
4 changed files with 127 additions and 53 deletions
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67
src/enc/analysis.c
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@ -20,51 +20,12 @@
extern "C" {
#endif
#define MAX_COEFF_THRESH 64
#define MAX_ITERS_K_MEANS 6
//-----------------------------------------------------------------------------
// Compute susceptibility based on DCT-coeff histograms:
// the higher, the "easier" the macroblock is to compress.
static int ClipAlpha(int alpha) {
return alpha < 0 ? 0 : alpha > 255 ? 255 : alpha;
}
static int GetAlpha(const int histo[MAX_COEFF_THRESH]) {
int num = 0, den = 0, val = 0;
int k;
int alpha;
for (k = 0; k < MAX_COEFF_THRESH; ++k) {
if (histo[k]) {
val += histo[k];
num += val * (k + 1);
den += (k + 1) * (k + 1);
}
}
// we scale the value to a usable [0..255] range
alpha = den ? 10 * num / den - 5 : 0;
return ClipAlpha(alpha);
}
static int CollectHistogram(const uint8_t* ref, const uint8_t* pred,
int start_block, int end_block) {
int histo[MAX_COEFF_THRESH] = { 0 };
int16_t out[16];
int j, k;
for (j = start_block; j < end_block; ++j) {
VP8FTransform(ref + VP8Scan[j], pred + VP8Scan[j], out);
for (k = 0; k < 16; ++k) {
const int v = abs(out[k]) >> 2;
if (v) {
const int bin = (v > MAX_COEFF_THRESH) ? MAX_COEFF_THRESH : v;
histo[bin - 1]++;
}
}
}
return GetAlpha(histo);
}
//-----------------------------------------------------------------------------
// Smooth the segment map by replacing isolated block by the majority of its
// neighbours.
@ -86,11 +47,11 @@ static void SmoothSegmentMap(VP8Encoder* const enc) {
cnt[mb[-w - 1].segment_]++; // top-left
cnt[mb[-w + 0].segment_]++; // top
cnt[mb[-w + 1].segment_]++; // top-right
cnt[mb[ - 1].segment_]++; // left
cnt[mb[ + 1].segment_]++; // right
cnt[mb[ w - 1].segment_]++; // bottom-left
cnt[mb[ w + 0].segment_]++; // bottom
cnt[mb[ w + 1].segment_]++; // bottom-right
cnt[mb[ - 1].segment_]++; // left
cnt[mb[ + 1].segment_]++; // right
cnt[mb[ w - 1].segment_]++; // bottom-left
cnt[mb[ w + 0].segment_]++; // bottom
cnt[mb[ w + 1].segment_]++; // bottom-right
for (n = 0; n < NUM_MB_SEGMENTS; ++n) {
if (cnt[n] >= majority_cnt_3_x_3_grid) {
majority_seg = n;
@ -278,9 +239,9 @@ static int MBAnalyzeBestIntra16Mode(VP8EncIterator* const it) {
VP8MakeLuma16Preds(it);
for (mode = 0; mode < max_mode; ++mode) {
const int alpha = CollectHistogram(it->yuv_in_ + Y_OFF,
it->yuv_p_ + VP8I16ModeOffsets[mode],
0, 16);
const int alpha = VP8CollectHistogram(it->yuv_in_ + Y_OFF,
it->yuv_p_ + VP8I16ModeOffsets[mode],
0, 16);
if (alpha > best_alpha) {
best_alpha = alpha;
best_mode = mode;
@ -303,9 +264,9 @@ static int MBAnalyzeBestIntra4Mode(VP8EncIterator* const it,
VP8MakeIntra4Preds(it);
for (mode = 0; mode < max_mode; ++mode) {
const int alpha = CollectHistogram(src,
it->yuv_p_ + VP8I4ModeOffsets[mode],
0, 1);
const int alpha = VP8CollectHistogram(src,
it->yuv_p_ + VP8I4ModeOffsets[mode],
0, 1);
if (alpha > best_mode_alpha) {
best_mode_alpha = alpha;
modes[it->i4_] = mode;
@ -329,9 +290,9 @@ static int MBAnalyzeBestUVMode(VP8EncIterator* const it) {
int mode;
VP8MakeChroma8Preds(it);
for (mode = 0; mode < max_mode; ++mode) {
const int alpha = CollectHistogram(it->yuv_in_ + U_OFF,
it->yuv_p_ + VP8UVModeOffsets[mode],
16, 16 + 4 + 4);
const int alpha = VP8CollectHistogram(it->yuv_in_ + U_OFF,
it->yuv_p_ + VP8UVModeOffsets[mode],
16, 16 + 4 + 4);
if (alpha > best_alpha) {
best_alpha = alpha;
best_mode = mode;