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detect and merge similar segments

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similar = same quant and filter strength.
This save some bits in the segment map

Change-Id: I6f594474ad82bddf013278d47089e43a02e07e63
This commit is contained in:
Pascal Massimino
2012-09-27 04:39:10 -07:00
committed by skal
parent 2afee60a7c
commit fee6627538
3 changed files with 90 additions and 45 deletions
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48
src/enc/quant.c
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@ -229,10 +229,50 @@ static double QualityToCompression(double q) {
return (c < 0.75) ? c * (2. / 3.) : 2. * c - 1.;
}
static int SegmentsAreEquivalent(const VP8SegmentInfo* const S1,
const VP8SegmentInfo* const S2) {
return (S1->quant_ == S2->quant_) && (S1->fstrength_ == S2->fstrength_);
}
static void SimplifySegments(VP8Encoder* const enc) {
int map[NUM_MB_SEGMENTS] = { 0, 1, 2, 3 };
const int num_segments = enc->segment_hdr_.num_segments_;
int num_final_segments = 1;
int s1, s2;
for (s1 = 1; s1 < num_segments; ++s1) { // find similar segments
const VP8SegmentInfo* const S1 = &enc->dqm_[s1];
int found = 0;
// check if we already have similar segment
for (s2 = 0; s2 < num_final_segments; ++s2) {
const VP8SegmentInfo* const S2 = &enc->dqm_[s2];
if (SegmentsAreEquivalent(S1, S2)) {
found = 1;
break;
}
}
map[s1] = s2;
if (!found) {
if (num_final_segments != s1) {
enc->dqm_[num_final_segments] = enc->dqm_[s1];
}
++num_final_segments;
}
}
if (num_final_segments < num_segments) { // Remap
int i = enc->mb_w_* enc->mb_h_;
while (i-- > 0) enc->mb_info_[i].segment_ = map[enc->mb_info_[i].segment_];
enc->segment_hdr_.num_segments_ = num_final_segments;
// Replicate the trailing segment infos (it's mostly cosmetics)
for (i = num_final_segments; i < num_segments; ++i) {
enc->dqm_[i] = enc->dqm_[num_final_segments - 1];
}
}
}
void VP8SetSegmentParams(VP8Encoder* const enc, float quality) {
int i;
int dq_uv_ac, dq_uv_dc;
const int num_segments = enc->config_->segments;
const int num_segments = enc->segment_hdr_.num_segments_;
const double amp = SNS_TO_DQ * enc->config_->sns_strength / 100. / 128.;
const double c_base = QualityToCompression(quality);
for (i = 0; i < num_segments; ++i) {
@ -281,9 +321,11 @@ void VP8SetSegmentParams(VP8Encoder* const enc, float quality) {
enc->dq_uv_dc_ = dq_uv_dc;
enc->dq_uv_ac_ = dq_uv_ac;
SetupMatrices(enc);
SetupFilterStrength(enc); // initialize segments' filtering, eventually
if (num_segments > 1) SimplifySegments(enc);
SetupMatrices(enc); // finalize quantization matrices
}
//------------------------------------------------------------------------------