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allow search with token buffer loop and fix PARTITION0 problem

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The convergence algo is noticeably faster and more accurate.

Try it with: 'cwebp -size xxxxx -pass 8 ...' or 'cwebp -psnr 39 -pass 8 ...'
for instance

Allow full-looping with TokenBuffer case, and make the non-TokenBuffer
case match too.

In case Partition0 is likely to overflow, retry encoding with harder
limits on max_i4_header_bits_.

This CL should make -partition_limit option somewhat useless,
since the fix made automatically (albeit in a non-optimal way yet).

Change-Id: I46fde3564188b13b89d4cb69f847a5f24b8c735b
This commit is contained in:
skal 2013-09-11 21:15:28 +02:00
parent b7d4e04255
commit 80b54e1c69
2 changed files with 171 additions and 72 deletions
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239
src/enc/frame.c
View File

@ -18,6 +18,7 @@
#include "./vp8enci.h"
#include "./cost.h"
#include "../webp/format_constants.h" // RIFF constants
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
@ -39,6 +40,63 @@ typedef struct {
CostArray* cost;
} VP8Residual;
//------------------------------------------------------------------------------
// multi-pass convergence
#define HEADER_SIZE_ESTIMATE (RIFF_HEADER_SIZE + CHUNK_HEADER_SIZE + \
VP8_FRAME_HEADER_SIZE)
#define DQ_LIMIT 0.4 // convergence is considered reached if dq < DQ_LIMIT
// we allow 2k of extra head-room in PARTITION0 limit.
#define PARTITION0_SIZE_LIMIT ((VP8_MAX_PARTITION0_SIZE - 2048ULL) << 11)
typedef struct { // struct for organizing convergence in either size or PSNR
int is_first;
float dq;
float q, last_q;
double value, last_value; // PSNR or size
double target;
int do_size_search;
} PassStats;
static int InitPassStats(const VP8Encoder* const enc, PassStats* const s) {
const uint64_t target_size = (uint64_t)enc->config_->target_size;
const int do_size_search = (target_size != 0);
const float target_PSNR = enc->config_->target_PSNR;
s->is_first = 1;
s->dq = 10.f;
s->q = s->last_q = enc->config_->quality;
s->target = do_size_search ? (double)target_size
: (target_PSNR > 0.) ? target_PSNR
: 40.; // default, just in case
s->value = s->last_value = 0.;
s->do_size_search = do_size_search;
return do_size_search;
}
static float Clamp(float v, float min, float max) {
return (v < min) ? min : (v > max) ? max : v;
}
static float ComputeNextQ(PassStats* const s) {
float dq;
if (s->is_first) {
dq = (s->value > s->target) ? -s->dq : s->dq;
s->is_first = 0;
} else if (s->value != s->last_value) {
const double slope = (s->target - s->value) / (s->last_value - s->value);
dq = slope * (s->last_q - s->q);
} else {
dq = 0.; // we're done?!
}
// Limit variable to avoid large swings.
s->dq = Clamp(dq, -30.f, 30.f);
s->last_q = s->q;
s->last_value = s->value;
s->q = Clamp(s->q + s->dq, 0.f, 100.f);
return s->q;
}
//------------------------------------------------------------------------------
// Tables for level coding
@ -674,40 +732,37 @@ static void StoreSideInfo(const VP8EncIterator* const it) {
#endif
}
static double GetPSNR(uint64_t mse, uint64_t size) {
return (mse > 0 && size > 0) ? 10. * log10(255. * 255. * size / mse) : 99;
}
//------------------------------------------------------------------------------
// StatLoop(): only collect statistics (number of skips, token usage, ...).
// This is used for deciding optimal probabilities. It also modifies the
// quantizer value if some target (size, PNSR) was specified.
#define kHeaderSizeEstimate (15 + 20 + 10) // TODO: fix better
static void SetLoopParams(VP8Encoder* const enc, float q) {
// Make sure the quality parameter is inside valid bounds
if (q < 0.) {
q = 0;
} else if (q > 100.) {
q = 100;
}
q = Clamp(q, 0.f, 100.f);
VP8SetSegmentParams(enc, q); // setup segment quantizations and filters
SetSegmentProbas(enc); // compute segment probabilities
ResetStats(enc);
ResetTokenStats(enc);
ResetSSE(enc);
}
static int OneStatPass(VP8Encoder* const enc, float q, VP8RDLevel rd_opt,
int nb_mbs, float* const PSNR, int percent_delta) {
static uint64_t OneStatPass(VP8Encoder* const enc, VP8RDLevel rd_opt,
int nb_mbs, int percent_delta,
PassStats* const s) {
VP8EncIterator it;
uint64_t size = 0;
uint64_t size_p0 = 0;
uint64_t distortion = 0;
const uint64_t pixel_count = nb_mbs * 384;
SetLoopParams(enc, q);
VP8IteratorInit(enc, &it);
SetLoopParams(enc, s->q);
do {
VP8ModeScore info;
VP8IteratorImport(&it, NULL);
@ -717,39 +772,43 @@ static int OneStatPass(VP8Encoder* const enc, float q, VP8RDLevel rd_opt,
}
RecordResiduals(&it, &info);
size += info.R + info.H;
size_p0 += info.H;
distortion += info.D;
if (percent_delta && !VP8IteratorProgress(&it, percent_delta))
return 0;
VP8IteratorSaveBoundary(&it);
} while (VP8IteratorNext(&it) && --nb_mbs > 0);
size += FinalizeSkipProba(enc);
size += FinalizeTokenProbas(&enc->proba_);
size += enc->segment_hdr_.size_;
size = ((size + 1024) >> 11) + kHeaderSizeEstimate;
if (PSNR) {
*PSNR = (float)(10.* log10(255. * 255. * pixel_count / distortion));
size_p0 += enc->segment_hdr_.size_;
if (s->do_size_search) {
size += FinalizeSkipProba(enc);
size += FinalizeTokenProbas(&enc->proba_);
size = ((size + size_p0 + 1024) >> 11) + HEADER_SIZE_ESTIMATE;
s->value = (double)size;
} else {
s->value = GetPSNR(distortion, pixel_count);
}
return (int)size;
return size_p0;
}
// successive refinement increments.
static const int dqs[] = { 20, 15, 10, 8, 6, 4, 2, 1, 0 };
static int StatLoop(VP8Encoder* const enc) {
const int method = enc->method_;
const int do_search = enc->do_search_;
const int fast_probe = ((method == 0 || method == 3) && !do_search);
float q = enc->config_->quality;
const int max_passes = enc->config_->pass;
int num_pass_left = enc->config_->pass;
const int task_percent = 20;
const int percent_per_pass = (task_percent + max_passes / 2) / max_passes;
const int percent_per_pass =
(task_percent + num_pass_left / 2) / num_pass_left;
const int final_percent = enc->percent_ + task_percent;
int pass;
int nb_mbs;
const VP8RDLevel rd_opt =
(method >= 3 || do_search) ? RD_OPT_BASIC : RD_OPT_NONE;
int nb_mbs = enc->mb_w_ * enc->mb_h_;
PassStats stats;
InitPassStats(enc, &stats);
ResetTokenStats(enc);
// Fast mode: quick analysis pass over few mbs. Better than nothing.
nb_mbs = enc->mb_w_ * enc->mb_h_;
if (fast_probe) {
if (method == 3) { // we need more stats for method 3 to be reliable.
nb_mbs = (nb_mbs > 200) ? nb_mbs >> 1 : 100;
@ -758,37 +817,35 @@ static int StatLoop(VP8Encoder* const enc) {
}
}
// No target size: just do several pass without changing 'q'
if (!do_search) {
for (pass = 0; pass < max_passes; ++pass) {
const VP8RDLevel rd_opt = (method >= 3) ? RD_OPT_BASIC : RD_OPT_NONE;
if (!OneStatPass(enc, q, rd_opt, nb_mbs, NULL, percent_per_pass)) {
return 0;
}
}
} else {
// binary search for a size close to target
for (pass = 0; pass < max_passes && (dqs[pass] > 0); ++pass) {
float PSNR;
int criterion;
const int size = OneStatPass(enc, q, RD_OPT_BASIC, nb_mbs, &PSNR,
percent_per_pass);
#if DEBUG_SEARCH
printf("#%d size=%d PSNR=%.2f q=%.2f\n", pass, size, PSNR, q);
while (num_pass_left-- > 0) {
const int is_last_pass = (fabs(stats.dq) <= DQ_LIMIT) ||
(num_pass_left == 0) ||
(enc->max_i4_header_bits_ == 0);
const uint64_t size_p0 =
OneStatPass(enc, rd_opt, nb_mbs, percent_per_pass, &stats);
if (size_p0 == 0) return 0;
#if (DEBUG_SEARCH > 0)
printf("#%d value:%.1lf -> %.1lf q:%.2f -> %.2f\n",
num_pass_left, stats.last_value, stats.value, stats.last_q, stats.q);
#endif
if (size == 0) return 0;
if (enc->config_->target_PSNR > 0) {
criterion = (PSNR < enc->config_->target_PSNR);
} else {
criterion = (size < enc->config_->target_size);
}
// dichotomize
if (criterion) {
q += dqs[pass];
} else {
q -= dqs[pass];
}
if (enc->max_i4_header_bits_ > 0 && size_p0 > PARTITION0_SIZE_LIMIT) {
++num_pass_left;
enc->max_i4_header_bits_ >>= 1; // strengthen header bit limitation...
continue; // ...and start over
}
if (is_last_pass) {
break;
}
// If no target size: just do several pass without changing 'q'
if (do_search) {
ComputeNextQ(&stats);
if (fabs(stats.dq) <= DQ_LIMIT) break;
}
}
if (!do_search || !stats.do_size_search) {
// Need to finalize probas now, since it wasn't done during the search.
FinalizeSkipProba(enc);
FinalizeTokenProbas(&enc->proba_);
}
VP8CalculateLevelCosts(&enc->proba_); // finalize costs
return WebPReportProgress(enc->pic_, final_percent, &enc->percent_);
@ -895,16 +952,23 @@ int VP8EncLoop(VP8Encoder* const enc) {
#if !defined(DISABLE_TOKEN_BUFFER)
#define MIN_COUNT 96 // minimum number of macroblocks before updating stats
#define MIN_COUNT 96 // minimum number of macroblocks before updating stats
int VP8EncTokenLoop(VP8Encoder* const enc) {
int ok;
// Roughly refresh the proba eight times per pass
int max_count = (enc->mb_w_ * enc->mb_h_) >> 3;
int num_pass_left = enc->config_->pass;
const int do_search = enc->do_search_;
VP8EncIterator it;
VP8Proba* const proba = &enc->proba_;
const VP8RDLevel rd_opt = enc->rd_opt_level_;
const uint64_t pixel_count = enc->mb_w_ * enc->mb_h_ * 384;
PassStats stats;
int ok;
InitPassStats(enc, &stats);
ok = PreLoopInitialize(enc);
if (!ok) return 0;
if (max_count < MIN_COUNT) max_count = MIN_COUNT;
@ -912,17 +976,18 @@ int VP8EncTokenLoop(VP8Encoder* const enc) {
assert(enc->use_tokens_);
assert(proba->use_skip_proba_ == 0);
assert(rd_opt >= RD_OPT_BASIC); // otherwise, token-buffer won't be useful
assert(!enc->do_search_); // TODO(skal): handle pass and dichotomy
SetLoopParams(enc, enc->config_->quality);
ok = PreLoopInitialize(enc);
if (!ok) return 0;
while (ok && num_pass_left-- > 0) {
const int is_last_pass = (fabs(stats.dq) <= DQ_LIMIT) ||
(num_pass_left == 0) ||
(enc->max_i4_header_bits_ == 0);
uint64_t size_p0 = 0;
uint64_t distortion = 0;
int cnt = max_count;
VP8IteratorInit(enc, &it);
if (num_pass_left == 0) {
SetLoopParams(enc, stats.q);
if (is_last_pass) {
ResetTokenStats(enc);
VP8InitFilter(&it); // don't collect stats until last pass (too costly)
}
VP8TBufferClear(&enc->tokens_);
@ -936,12 +1001,14 @@ int VP8EncTokenLoop(VP8Encoder* const enc) {
}
VP8Decimate(&it, &info, rd_opt);
RecordTokens(&it, &info, &enc->tokens_);
size_p0 += info.H;
distortion += info.D;
#ifdef WEBP_EXPERIMENTAL_FEATURES
if (enc->use_layer_) {
VP8EncCodeLayerBlock(&it);
}
#endif
if (num_pass_left == 0) {
if (is_last_pass) {
StoreSideInfo(&it);
VP8StoreFilterStats(&it);
VP8IteratorExport(&it);
@ -949,13 +1016,45 @@ int VP8EncTokenLoop(VP8Encoder* const enc) {
}
VP8IteratorSaveBoundary(&it);
} while (ok && VP8IteratorNext(&it));
if (!ok) break;
size_p0 += enc->segment_hdr_.size_;
if (stats.do_size_search) {
uint64_t size = FinalizeTokenProbas(&enc->proba_);
size += VP8EstimateTokenSize(&enc->tokens_,
(const uint8_t*)proba->coeffs_);
size = (size + size_p0 + 1024) >> 11; // -> size in bytes
size += HEADER_SIZE_ESTIMATE;
stats.value = (double)size;
} else { // compute and store PSNR
stats.value = GetPSNR(distortion, pixel_count);
}
#if (DEBUG_SEARCH > 0)
printf("#%2d metric:%.1lf -> %.1lf last_q=%.2lf q=%.2lf dq=%.2lf\n",
num_pass_left, stats.last_value, stats.value,
stats.last_q, stats.q, stats.dq);
#endif
if (size_p0 > PARTITION0_SIZE_LIMIT) {
++num_pass_left;
enc->max_i4_header_bits_ >>= 1; // strengthen header bit limitation...
continue; // ...and start over
}
if (is_last_pass) {
break; // done
}
if (do_search) {
ComputeNextQ(&stats); // Adjust q
}
}
ok = ok && WebPReportProgress(enc->pic_, enc->percent_ + 20, &enc->percent_);
if (ok) {
FinalizeTokenProbas(proba);
if (!stats.do_size_search) {
FinalizeTokenProbas(&enc->proba_);
}
ok = VP8EmitTokens(&enc->tokens_, enc->parts_ + 0,
(const uint8_t*)proba->coeffs_, 1);
}
ok = ok && WebPReportProgress(enc->pic_, enc->percent_ + 20, &enc->percent_);
return PostLoopFinalize(&it, ok);
}

4
src/enc/webpenc.c
View File

@ -136,7 +136,7 @@ static void MapConfigToTools(VP8Encoder* const enc) {
enc->do_search_ = (config->target_size > 0 || config->target_PSNR > 0);
if (!config->low_memory) {
#if !defined(DISABLE_TOKEN_BUFFER)
enc->use_tokens_ = (method >= 3) && !enc->do_search_;
enc->use_tokens_ = (enc->rd_opt_level_ >= RD_OPT_BASIC); // need rd stats
#endif
if (enc->use_tokens_) {
enc->num_parts_ = 1; // doesn't work with multi-partition
@ -281,7 +281,7 @@ static int DeleteVP8Encoder(VP8Encoder* enc) {
//------------------------------------------------------------------------------
static double GetPSNR(uint64_t err, uint64_t size) {
return err ? 10. * log10(255. * 255. * size / err) : 99.;
return (err > 0 && size > 0) ? 10. * log10(255. * 255. * size / err) : 99.;
}
static void FinalizePSNR(const VP8Encoder* const enc) {