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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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43
src/enc/analysis.c
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@ -68,47 +68,7 @@ static void SmoothSegmentMap(VP8Encoder* const enc) {
}
//------------------------------------------------------------------------------
// Finalize Segment probability based on the coding tree
static int GetProba(int a, int b) {
int proba;
const int total = a + b;
if (total == 0) return 255; // that's the default probability.
proba = (255 * a + total / 2) / total;
return proba;
}
static void SetSegmentProbas(VP8Encoder* const enc) {
int p[NUM_MB_SEGMENTS] = { 0 };
int n;
for (n = 0; n < enc->mb_w_ * enc->mb_h_; ++n) {
const VP8MBInfo* const mb = &enc->mb_info_[n];
p[mb->segment_]++;
}
if (enc->pic_->stats) {
for (n = 0; n < NUM_MB_SEGMENTS; ++n) {
enc->pic_->stats->segment_size[n] = p[n];
}
}
if (enc->segment_hdr_.num_segments_ > 1) {
uint8_t* const probas = enc->proba_.segments_;
probas[0] = GetProba(p[0] + p[1], p[2] + p[3]);
probas[1] = GetProba(p[0], p[1]);
probas[2] = GetProba(p[2], p[3]);
enc->segment_hdr_.update_map_ =
(probas[0] != 255) || (probas[1] != 255) || (probas[2] != 255);
enc->segment_hdr_.size_ =
p[0] * (VP8BitCost(0, probas[0]) + VP8BitCost(0, probas[1])) +
p[1] * (VP8BitCost(0, probas[0]) + VP8BitCost(1, probas[1])) +
p[2] * (VP8BitCost(1, probas[0]) + VP8BitCost(0, probas[2])) +
p[3] * (VP8BitCost(1, probas[0]) + VP8BitCost(1, probas[2]));
} else {
enc->segment_hdr_.update_map_ = 0;
enc->segment_hdr_.size_ = 0;
}
}
// set segment susceptibility alpha_ / beta_
static WEBP_INLINE int clip(int v, int m, int M) {
return (v < m) ? m : (v > M) ? M : v;
@ -255,7 +215,6 @@ static void AssignSegments(VP8Encoder* const enc,
if (smooth) SmoothSegmentMap(enc);
}
SetSegmentProbas(enc); // Assign final proba
SetSegmentAlphas(enc, centers, weighted_average); // pick some alphas.
}