diff options
Diffstat (limited to 'thirdparty/libwebp/enc/frame.c')
| -rw-r--r-- | thirdparty/libwebp/enc/frame.c | 850 |
1 files changed, 850 insertions, 0 deletions
diff --git a/thirdparty/libwebp/enc/frame.c b/thirdparty/libwebp/enc/frame.c new file mode 100644 index 0000000000..5b7a40b9ad --- /dev/null +++ b/thirdparty/libwebp/enc/frame.c @@ -0,0 +1,850 @@ +// Copyright 2011 Google Inc. All Rights Reserved. +// +// Use of this source code is governed by a BSD-style license +// that can be found in the COPYING file in the root of the source +// tree. An additional intellectual property rights grant can be found +// in the file PATENTS. All contributing project authors may +// be found in the AUTHORS file in the root of the source tree. +// ----------------------------------------------------------------------------- +// +// frame coding and analysis +// +// Author: Skal (pascal.massimino@gmail.com) + +#include <string.h> +#include <math.h> + +#include "./cost.h" +#include "./vp8enci.h" +#include "../dsp/dsp.h" +#include "../webp/format_constants.h" // RIFF constants + +#define SEGMENT_VISU 0 +#define DEBUG_SEARCH 0 // useful to track search convergence + +//------------------------------------------------------------------------------ +// 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 = (float)(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 + +const uint8_t VP8Cat3[] = { 173, 148, 140 }; +const uint8_t VP8Cat4[] = { 176, 155, 140, 135 }; +const uint8_t VP8Cat5[] = { 180, 157, 141, 134, 130 }; +const uint8_t VP8Cat6[] = + { 254, 254, 243, 230, 196, 177, 153, 140, 133, 130, 129 }; + +//------------------------------------------------------------------------------ +// Reset the statistics about: number of skips, token proba, level cost,... + +static void ResetStats(VP8Encoder* const enc) { + VP8EncProba* const proba = &enc->proba_; + VP8CalculateLevelCosts(proba); + proba->nb_skip_ = 0; +} + +//------------------------------------------------------------------------------ +// Skip decision probability + +#define SKIP_PROBA_THRESHOLD 250 // value below which using skip_proba is OK. + +static int CalcSkipProba(uint64_t nb, uint64_t total) { + return (int)(total ? (total - nb) * 255 / total : 255); +} + +// Returns the bit-cost for coding the skip probability. +static int FinalizeSkipProba(VP8Encoder* const enc) { + VP8EncProba* const proba = &enc->proba_; + const int nb_mbs = enc->mb_w_ * enc->mb_h_; + const int nb_events = proba->nb_skip_; + int size; + proba->skip_proba_ = CalcSkipProba(nb_events, nb_mbs); + proba->use_skip_proba_ = (proba->skip_proba_ < SKIP_PROBA_THRESHOLD); + size = 256; // 'use_skip_proba' bit + if (proba->use_skip_proba_) { + size += nb_events * VP8BitCost(1, proba->skip_proba_) + + (nb_mbs - nb_events) * VP8BitCost(0, proba->skip_proba_); + size += 8 * 256; // cost of signaling the skip_proba_ itself. + } + return size; +} + +// Collect statistics and deduce probabilities for next coding pass. +// Return the total bit-cost for coding the probability updates. +static int CalcTokenProba(int nb, int total) { + assert(nb <= total); + return nb ? (255 - nb * 255 / total) : 255; +} + +// Cost of coding 'nb' 1's and 'total-nb' 0's using 'proba' probability. +static int BranchCost(int nb, int total, int proba) { + return nb * VP8BitCost(1, proba) + (total - nb) * VP8BitCost(0, proba); +} + +static void ResetTokenStats(VP8Encoder* const enc) { + VP8EncProba* const proba = &enc->proba_; + memset(proba->stats_, 0, sizeof(proba->stats_)); +} + +static int FinalizeTokenProbas(VP8EncProba* const proba) { + int has_changed = 0; + int size = 0; + int t, b, c, p; + for (t = 0; t < NUM_TYPES; ++t) { + for (b = 0; b < NUM_BANDS; ++b) { + for (c = 0; c < NUM_CTX; ++c) { + for (p = 0; p < NUM_PROBAS; ++p) { + const proba_t stats = proba->stats_[t][b][c][p]; + const int nb = (stats >> 0) & 0xffff; + const int total = (stats >> 16) & 0xffff; + const int update_proba = VP8CoeffsUpdateProba[t][b][c][p]; + const int old_p = VP8CoeffsProba0[t][b][c][p]; + const int new_p = CalcTokenProba(nb, total); + const int old_cost = BranchCost(nb, total, old_p) + + VP8BitCost(0, update_proba); + const int new_cost = BranchCost(nb, total, new_p) + + VP8BitCost(1, update_proba) + + 8 * 256; + const int use_new_p = (old_cost > new_cost); + size += VP8BitCost(use_new_p, update_proba); + if (use_new_p) { // only use proba that seem meaningful enough. + proba->coeffs_[t][b][c][p] = new_p; + has_changed |= (new_p != old_p); + size += 8 * 256; + } else { + proba->coeffs_[t][b][c][p] = old_p; + } + } + } + } + } + proba->dirty_ = has_changed; + return size; +} + +//------------------------------------------------------------------------------ +// Finalize Segment probability based on the coding tree + +static int GetProba(int a, int b) { + const int total = a + b; + return (total == 0) ? 255 // that's the default probability. + : (255 * a + total / 2) / total; // rounded 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; + } +} + +//------------------------------------------------------------------------------ +// Coefficient coding + +static int PutCoeffs(VP8BitWriter* const bw, int ctx, const VP8Residual* res) { + int n = res->first; + // should be prob[VP8EncBands[n]], but it's equivalent for n=0 or 1 + const uint8_t* p = res->prob[n][ctx]; + if (!VP8PutBit(bw, res->last >= 0, p[0])) { + return 0; + } + + while (n < 16) { + const int c = res->coeffs[n++]; + const int sign = c < 0; + int v = sign ? -c : c; + if (!VP8PutBit(bw, v != 0, p[1])) { + p = res->prob[VP8EncBands[n]][0]; + continue; + } + if (!VP8PutBit(bw, v > 1, p[2])) { + p = res->prob[VP8EncBands[n]][1]; + } else { + if (!VP8PutBit(bw, v > 4, p[3])) { + if (VP8PutBit(bw, v != 2, p[4])) + VP8PutBit(bw, v == 4, p[5]); + } else if (!VP8PutBit(bw, v > 10, p[6])) { + if (!VP8PutBit(bw, v > 6, p[7])) { + VP8PutBit(bw, v == 6, 159); + } else { + VP8PutBit(bw, v >= 9, 165); + VP8PutBit(bw, !(v & 1), 145); + } + } else { + int mask; + const uint8_t* tab; + if (v < 3 + (8 << 1)) { // VP8Cat3 (3b) + VP8PutBit(bw, 0, p[8]); + VP8PutBit(bw, 0, p[9]); + v -= 3 + (8 << 0); + mask = 1 << 2; + tab = VP8Cat3; + } else if (v < 3 + (8 << 2)) { // VP8Cat4 (4b) + VP8PutBit(bw, 0, p[8]); + VP8PutBit(bw, 1, p[9]); + v -= 3 + (8 << 1); + mask = 1 << 3; + tab = VP8Cat4; + } else if (v < 3 + (8 << 3)) { // VP8Cat5 (5b) + VP8PutBit(bw, 1, p[8]); + VP8PutBit(bw, 0, p[10]); + v -= 3 + (8 << 2); + mask = 1 << 4; + tab = VP8Cat5; + } else { // VP8Cat6 (11b) + VP8PutBit(bw, 1, p[8]); + VP8PutBit(bw, 1, p[10]); + v -= 3 + (8 << 3); + mask = 1 << 10; + tab = VP8Cat6; + } + while (mask) { + VP8PutBit(bw, !!(v & mask), *tab++); + mask >>= 1; + } + } + p = res->prob[VP8EncBands[n]][2]; + } + VP8PutBitUniform(bw, sign); + if (n == 16 || !VP8PutBit(bw, n <= res->last, p[0])) { + return 1; // EOB + } + } + return 1; +} + +static void CodeResiduals(VP8BitWriter* const bw, VP8EncIterator* const it, + const VP8ModeScore* const rd) { + int x, y, ch; + VP8Residual res; + uint64_t pos1, pos2, pos3; + const int i16 = (it->mb_->type_ == 1); + const int segment = it->mb_->segment_; + VP8Encoder* const enc = it->enc_; + + VP8IteratorNzToBytes(it); + + pos1 = VP8BitWriterPos(bw); + if (i16) { + VP8InitResidual(0, 1, enc, &res); + VP8SetResidualCoeffs(rd->y_dc_levels, &res); + it->top_nz_[8] = it->left_nz_[8] = + PutCoeffs(bw, it->top_nz_[8] + it->left_nz_[8], &res); + VP8InitResidual(1, 0, enc, &res); + } else { + VP8InitResidual(0, 3, enc, &res); + } + + // luma-AC + for (y = 0; y < 4; ++y) { + for (x = 0; x < 4; ++x) { + const int ctx = it->top_nz_[x] + it->left_nz_[y]; + VP8SetResidualCoeffs(rd->y_ac_levels[x + y * 4], &res); + it->top_nz_[x] = it->left_nz_[y] = PutCoeffs(bw, ctx, &res); + } + } + pos2 = VP8BitWriterPos(bw); + + // U/V + VP8InitResidual(0, 2, enc, &res); + for (ch = 0; ch <= 2; ch += 2) { + for (y = 0; y < 2; ++y) { + for (x = 0; x < 2; ++x) { + const int ctx = it->top_nz_[4 + ch + x] + it->left_nz_[4 + ch + y]; + VP8SetResidualCoeffs(rd->uv_levels[ch * 2 + x + y * 2], &res); + it->top_nz_[4 + ch + x] = it->left_nz_[4 + ch + y] = + PutCoeffs(bw, ctx, &res); + } + } + } + pos3 = VP8BitWriterPos(bw); + it->luma_bits_ = pos2 - pos1; + it->uv_bits_ = pos3 - pos2; + it->bit_count_[segment][i16] += it->luma_bits_; + it->bit_count_[segment][2] += it->uv_bits_; + VP8IteratorBytesToNz(it); +} + +// Same as CodeResiduals, but doesn't actually write anything. +// Instead, it just records the event distribution. +static void RecordResiduals(VP8EncIterator* const it, + const VP8ModeScore* const rd) { + int x, y, ch; + VP8Residual res; + VP8Encoder* const enc = it->enc_; + + VP8IteratorNzToBytes(it); + + if (it->mb_->type_ == 1) { // i16x16 + VP8InitResidual(0, 1, enc, &res); + VP8SetResidualCoeffs(rd->y_dc_levels, &res); + it->top_nz_[8] = it->left_nz_[8] = + VP8RecordCoeffs(it->top_nz_[8] + it->left_nz_[8], &res); + VP8InitResidual(1, 0, enc, &res); + } else { + VP8InitResidual(0, 3, enc, &res); + } + + // luma-AC + for (y = 0; y < 4; ++y) { + for (x = 0; x < 4; ++x) { + const int ctx = it->top_nz_[x] + it->left_nz_[y]; + VP8SetResidualCoeffs(rd->y_ac_levels[x + y * 4], &res); + it->top_nz_[x] = it->left_nz_[y] = VP8RecordCoeffs(ctx, &res); + } + } + + // U/V + VP8InitResidual(0, 2, enc, &res); + for (ch = 0; ch <= 2; ch += 2) { + for (y = 0; y < 2; ++y) { + for (x = 0; x < 2; ++x) { + const int ctx = it->top_nz_[4 + ch + x] + it->left_nz_[4 + ch + y]; + VP8SetResidualCoeffs(rd->uv_levels[ch * 2 + x + y * 2], &res); + it->top_nz_[4 + ch + x] = it->left_nz_[4 + ch + y] = + VP8RecordCoeffs(ctx, &res); + } + } + } + + VP8IteratorBytesToNz(it); +} + +//------------------------------------------------------------------------------ +// Token buffer + +#if !defined(DISABLE_TOKEN_BUFFER) + +static int RecordTokens(VP8EncIterator* const it, const VP8ModeScore* const rd, + VP8TBuffer* const tokens) { + int x, y, ch; + VP8Residual res; + VP8Encoder* const enc = it->enc_; + + VP8IteratorNzToBytes(it); + if (it->mb_->type_ == 1) { // i16x16 + const int ctx = it->top_nz_[8] + it->left_nz_[8]; + VP8InitResidual(0, 1, enc, &res); + VP8SetResidualCoeffs(rd->y_dc_levels, &res); + it->top_nz_[8] = it->left_nz_[8] = + VP8RecordCoeffTokens(ctx, 1, + res.first, res.last, res.coeffs, tokens); + VP8RecordCoeffs(ctx, &res); + VP8InitResidual(1, 0, enc, &res); + } else { + VP8InitResidual(0, 3, enc, &res); + } + + // luma-AC + for (y = 0; y < 4; ++y) { + for (x = 0; x < 4; ++x) { + const int ctx = it->top_nz_[x] + it->left_nz_[y]; + VP8SetResidualCoeffs(rd->y_ac_levels[x + y * 4], &res); + it->top_nz_[x] = it->left_nz_[y] = + VP8RecordCoeffTokens(ctx, res.coeff_type, + res.first, res.last, res.coeffs, tokens); + VP8RecordCoeffs(ctx, &res); + } + } + + // U/V + VP8InitResidual(0, 2, enc, &res); + for (ch = 0; ch <= 2; ch += 2) { + for (y = 0; y < 2; ++y) { + for (x = 0; x < 2; ++x) { + const int ctx = it->top_nz_[4 + ch + x] + it->left_nz_[4 + ch + y]; + VP8SetResidualCoeffs(rd->uv_levels[ch * 2 + x + y * 2], &res); + it->top_nz_[4 + ch + x] = it->left_nz_[4 + ch + y] = + VP8RecordCoeffTokens(ctx, 2, + res.first, res.last, res.coeffs, tokens); + VP8RecordCoeffs(ctx, &res); + } + } + } + VP8IteratorBytesToNz(it); + return !tokens->error_; +} + +#endif // !DISABLE_TOKEN_BUFFER + +//------------------------------------------------------------------------------ +// ExtraInfo map / Debug function + +#if SEGMENT_VISU +static void SetBlock(uint8_t* p, int value, int size) { + int y; + for (y = 0; y < size; ++y) { + memset(p, value, size); + p += BPS; + } +} +#endif + +static void ResetSSE(VP8Encoder* const enc) { + enc->sse_[0] = 0; + enc->sse_[1] = 0; + enc->sse_[2] = 0; + // Note: enc->sse_[3] is managed by alpha.c + enc->sse_count_ = 0; +} + +static void StoreSSE(const VP8EncIterator* const it) { + VP8Encoder* const enc = it->enc_; + const uint8_t* const in = it->yuv_in_; + const uint8_t* const out = it->yuv_out_; + // Note: not totally accurate at boundary. And doesn't include in-loop filter. + enc->sse_[0] += VP8SSE16x16(in + Y_OFF_ENC, out + Y_OFF_ENC); + enc->sse_[1] += VP8SSE8x8(in + U_OFF_ENC, out + U_OFF_ENC); + enc->sse_[2] += VP8SSE8x8(in + V_OFF_ENC, out + V_OFF_ENC); + enc->sse_count_ += 16 * 16; +} + +static void StoreSideInfo(const VP8EncIterator* const it) { + VP8Encoder* const enc = it->enc_; + const VP8MBInfo* const mb = it->mb_; + WebPPicture* const pic = enc->pic_; + + if (pic->stats != NULL) { + StoreSSE(it); + enc->block_count_[0] += (mb->type_ == 0); + enc->block_count_[1] += (mb->type_ == 1); + enc->block_count_[2] += (mb->skip_ != 0); + } + + if (pic->extra_info != NULL) { + uint8_t* const info = &pic->extra_info[it->x_ + it->y_ * enc->mb_w_]; + switch (pic->extra_info_type) { + case 1: *info = mb->type_; break; + case 2: *info = mb->segment_; break; + case 3: *info = enc->dqm_[mb->segment_].quant_; break; + case 4: *info = (mb->type_ == 1) ? it->preds_[0] : 0xff; break; + case 5: *info = mb->uv_mode_; break; + case 6: { + const int b = (int)((it->luma_bits_ + it->uv_bits_ + 7) >> 3); + *info = (b > 255) ? 255 : b; break; + } + case 7: *info = mb->alpha_; break; + default: *info = 0; break; + } + } +#if SEGMENT_VISU // visualize segments and prediction modes + SetBlock(it->yuv_out_ + Y_OFF_ENC, mb->segment_ * 64, 16); + SetBlock(it->yuv_out_ + U_OFF_ENC, it->preds_[0] * 64, 8); + SetBlock(it->yuv_out_ + V_OFF_ENC, mb->uv_mode_ * 64, 8); +#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, PSNR) was specified. + +static void SetLoopParams(VP8Encoder* const enc, float q) { + // Make sure the quality parameter is inside valid bounds + q = Clamp(q, 0.f, 100.f); + + VP8SetSegmentParams(enc, q); // setup segment quantizations and filters + SetSegmentProbas(enc); // compute segment probabilities + + ResetStats(enc); + ResetSSE(enc); +} + +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; + + VP8IteratorInit(enc, &it); + SetLoopParams(enc, s->q); + do { + VP8ModeScore info; + VP8IteratorImport(&it, NULL); + if (VP8Decimate(&it, &info, rd_opt)) { + // Just record the number of skips and act like skip_proba is not used. + enc->proba_.nb_skip_++; + } + 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_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 size_p0; +} + +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); + int num_pass_left = enc->config_->pass; + const int task_percent = 20; + const int percent_per_pass = + (task_percent + num_pass_left / 2) / num_pass_left; + const int final_percent = enc->percent_ + task_percent; + 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. + 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; + } else { + nb_mbs = (nb_mbs > 200) ? nb_mbs >> 2 : 50; + } + } + + 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 (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_); +} + +//------------------------------------------------------------------------------ +// Main loops +// + +static const int kAverageBytesPerMB[8] = { 50, 24, 16, 9, 7, 5, 3, 2 }; + +static int PreLoopInitialize(VP8Encoder* const enc) { + int p; + int ok = 1; + const int average_bytes_per_MB = kAverageBytesPerMB[enc->base_quant_ >> 4]; + const int bytes_per_parts = + enc->mb_w_ * enc->mb_h_ * average_bytes_per_MB / enc->num_parts_; + // Initialize the bit-writers + for (p = 0; ok && p < enc->num_parts_; ++p) { + ok = VP8BitWriterInit(enc->parts_ + p, bytes_per_parts); + } + if (!ok) { + VP8EncFreeBitWriters(enc); // malloc error occurred + WebPEncodingSetError(enc->pic_, VP8_ENC_ERROR_OUT_OF_MEMORY); + } + return ok; +} + +static int PostLoopFinalize(VP8EncIterator* const it, int ok) { + VP8Encoder* const enc = it->enc_; + if (ok) { // Finalize the partitions, check for extra errors. + int p; + for (p = 0; p < enc->num_parts_; ++p) { + VP8BitWriterFinish(enc->parts_ + p); + ok &= !enc->parts_[p].error_; + } + } + + if (ok) { // All good. Finish up. + if (enc->pic_->stats != NULL) { // finalize byte counters... + int i, s; + for (i = 0; i <= 2; ++i) { + for (s = 0; s < NUM_MB_SEGMENTS; ++s) { + enc->residual_bytes_[i][s] = (int)((it->bit_count_[s][i] + 7) >> 3); + } + } + } + VP8AdjustFilterStrength(it); // ...and store filter stats. + } else { + // Something bad happened -> need to do some memory cleanup. + VP8EncFreeBitWriters(enc); + } + return ok; +} + +//------------------------------------------------------------------------------ +// VP8EncLoop(): does the final bitstream coding. + +static void ResetAfterSkip(VP8EncIterator* const it) { + if (it->mb_->type_ == 1) { + *it->nz_ = 0; // reset all predictors + it->left_nz_[8] = 0; + } else { + *it->nz_ &= (1 << 24); // preserve the dc_nz bit + } +} + +int VP8EncLoop(VP8Encoder* const enc) { + VP8EncIterator it; + int ok = PreLoopInitialize(enc); + if (!ok) return 0; + + StatLoop(enc); // stats-collection loop + + VP8IteratorInit(enc, &it); + VP8InitFilter(&it); + do { + VP8ModeScore info; + const int dont_use_skip = !enc->proba_.use_skip_proba_; + const VP8RDLevel rd_opt = enc->rd_opt_level_; + + VP8IteratorImport(&it, NULL); + // Warning! order is important: first call VP8Decimate() and + // *then* decide how to code the skip decision if there's one. + if (!VP8Decimate(&it, &info, rd_opt) || dont_use_skip) { + CodeResiduals(it.bw_, &it, &info); + } else { // reset predictors after a skip + ResetAfterSkip(&it); + } + StoreSideInfo(&it); + VP8StoreFilterStats(&it); + VP8IteratorExport(&it); + ok = VP8IteratorProgress(&it, 20); + VP8IteratorSaveBoundary(&it); + } while (ok && VP8IteratorNext(&it)); + + return PostLoopFinalize(&it, ok); +} + +//------------------------------------------------------------------------------ +// Single pass using Token Buffer. + +#if !defined(DISABLE_TOKEN_BUFFER) + +#define MIN_COUNT 96 // minimum number of macroblocks before updating stats + +int VP8EncTokenLoop(VP8Encoder* const enc) { + // 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; + VP8EncProba* 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; + + assert(enc->num_parts_ == 1); + assert(enc->use_tokens_); + assert(proba->use_skip_proba_ == 0); + assert(rd_opt >= RD_OPT_BASIC); // otherwise, token-buffer won't be useful + assert(num_pass_left > 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); + SetLoopParams(enc, stats.q); + if (is_last_pass) { + ResetTokenStats(enc); + VP8InitFilter(&it); // don't collect stats until last pass (too costly) + } + VP8TBufferClear(&enc->tokens_); + do { + VP8ModeScore info; + VP8IteratorImport(&it, NULL); + if (--cnt < 0) { + FinalizeTokenProbas(proba); + VP8CalculateLevelCosts(proba); // refresh cost tables for rd-opt + cnt = max_count; + } + VP8Decimate(&it, &info, rd_opt); + ok = RecordTokens(&it, &info, &enc->tokens_); + if (!ok) { + WebPEncodingSetError(enc->pic_, VP8_ENC_ERROR_OUT_OF_MEMORY); + break; + } + size_p0 += info.H; + distortion += info.D; + if (is_last_pass) { + StoreSideInfo(&it); + VP8StoreFilterStats(&it); + VP8IteratorExport(&it); + ok = VP8IteratorProgress(&it, 20); + } + 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 + } + } + if (ok) { + 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); +} + +#else + +int VP8EncTokenLoop(VP8Encoder* const enc) { + (void)enc; + return 0; // we shouldn't be here. +} + +#endif // DISABLE_TOKEN_BUFFER + +//------------------------------------------------------------------------------ + |