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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
View File

@ -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.
}

44
src/enc/frame.c
View File

@ -211,6 +211,49 @@ static int FinalizeTokenProbas(VP8Encoder* const enc) {
return size;
}
//------------------------------------------------------------------------------
// 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 != NULL) {
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;
}
}
//------------------------------------------------------------------------------
// helper functions for residuals struct VP8Residual.
@ -849,6 +892,7 @@ static int OneStatPass(VP8Encoder* const enc, float q, int rd_opt, int nb_mbs,
}
VP8SetSegmentParams(enc, q); // setup segment quantizations and filters
SetSegmentProbas(enc); // compute segment probabilities
ResetStats(enc);
ResetTokenStats(enc);

48
src/enc/quant.c
View File

@ -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
}
//------------------------------------------------------------------------------