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Unified Diff: third_party/libwebp/enc/quant.c

Issue 2651883004: libwebp-0.6.0-rc1 (Closed)
Patch Set: Created 3 years, 11 months ago
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Index: third_party/libwebp/enc/quant.c
diff --git a/third_party/libwebp/enc/quant.c b/third_party/libwebp/enc/quant.c
deleted file mode 100644
index 07ffaf0aebc08303e7b10344a4d66db1f4c39ed3..0000000000000000000000000000000000000000
--- a/third_party/libwebp/enc/quant.c
+++ /dev/null
@@ -1,1284 +0,0 @@
-// 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.
-// -----------------------------------------------------------------------------
-//
-// Quantization
-//
-// Author: Skal (pascal.massimino@gmail.com)
-
-#include <assert.h>
-#include <math.h>
-#include <stdlib.h> // for abs()
-
-#include "./vp8enci.h"
-#include "./cost.h"
-
-#define DO_TRELLIS_I4 1
-#define DO_TRELLIS_I16 1 // not a huge gain, but ok at low bitrate.
-#define DO_TRELLIS_UV 0 // disable trellis for UV. Risky. Not worth.
-#define USE_TDISTO 1
-
-#define MID_ALPHA 64 // neutral value for susceptibility
-#define MIN_ALPHA 30 // lowest usable value for susceptibility
-#define MAX_ALPHA 100 // higher meaningful value for susceptibility
-
-#define SNS_TO_DQ 0.9 // Scaling constant between the sns value and the QP
- // power-law modulation. Must be strictly less than 1.
-
-// number of non-zero coeffs below which we consider the block very flat
-// (and apply a penalty to complex predictions)
-#define FLATNESS_LIMIT_I16 10 // I16 mode
-#define FLATNESS_LIMIT_I4 3 // I4 mode
-#define FLATNESS_LIMIT_UV 2 // UV mode
-#define FLATNESS_PENALTY 140 // roughly ~1bit per block
-
-#define MULT_8B(a, b) (((a) * (b) + 128) >> 8)
-
-#define RD_DISTO_MULT 256 // distortion multiplier (equivalent of lambda)
-
-// #define DEBUG_BLOCK
-
-//------------------------------------------------------------------------------
-
-#if defined(DEBUG_BLOCK)
-
-#include <stdio.h>
-#include <stdlib.h>
-
-static void PrintBlockInfo(const VP8EncIterator* const it,
- const VP8ModeScore* const rd) {
- int i, j;
- const int is_i16 = (it->mb_->type_ == 1);
- const uint8_t* const y_in = it->yuv_in_ + Y_OFF_ENC;
- const uint8_t* const y_out = it->yuv_out_ + Y_OFF_ENC;
- const uint8_t* const uv_in = it->yuv_in_ + U_OFF_ENC;
- const uint8_t* const uv_out = it->yuv_out_ + U_OFF_ENC;
- printf("SOURCE / OUTPUT / ABS DELTA\n");
- for (j = 0; j < 16; ++j) {
- for (i = 0; i < 16; ++i) printf("%3d ", y_in[i + j * BPS]);
- printf(" ");
- for (i = 0; i < 16; ++i) printf("%3d ", y_out[i + j * BPS]);
- printf(" ");
- for (i = 0; i < 16; ++i) {
- printf("%1d ", abs(y_in[i + j * BPS] - y_out[i + j * BPS]));
- }
- printf("\n");
- }
- printf("\n"); // newline before the U/V block
- for (j = 0; j < 8; ++j) {
- for (i = 0; i < 8; ++i) printf("%3d ", uv_in[i + j * BPS]);
- printf(" ");
- for (i = 8; i < 16; ++i) printf("%3d ", uv_in[i + j * BPS]);
- printf(" ");
- for (i = 0; i < 8; ++i) printf("%3d ", uv_out[i + j * BPS]);
- printf(" ");
- for (i = 8; i < 16; ++i) printf("%3d ", uv_out[i + j * BPS]);
- printf(" ");
- for (i = 0; i < 8; ++i) {
- printf("%1d ", abs(uv_out[i + j * BPS] - uv_in[i + j * BPS]));
- }
- printf(" ");
- for (i = 8; i < 16; ++i) {
- printf("%1d ", abs(uv_out[i + j * BPS] - uv_in[i + j * BPS]));
- }
- printf("\n");
- }
- printf("\nD:%d SD:%d R:%d H:%d nz:0x%x score:%d\n",
- (int)rd->D, (int)rd->SD, (int)rd->R, (int)rd->H, (int)rd->nz,
- (int)rd->score);
- if (is_i16) {
- printf("Mode: %d\n", rd->mode_i16);
- printf("y_dc_levels:");
- for (i = 0; i < 16; ++i) printf("%3d ", rd->y_dc_levels[i]);
- printf("\n");
- } else {
- printf("Modes[16]: ");
- for (i = 0; i < 16; ++i) printf("%d ", rd->modes_i4[i]);
- printf("\n");
- }
- printf("y_ac_levels:\n");
- for (j = 0; j < 16; ++j) {
- for (i = is_i16 ? 1 : 0; i < 16; ++i) {
- printf("%4d ", rd->y_ac_levels[j][i]);
- }
- printf("\n");
- }
- printf("\n");
- printf("uv_levels (mode=%d):\n", rd->mode_uv);
- for (j = 0; j < 8; ++j) {
- for (i = 0; i < 16; ++i) {
- printf("%4d ", rd->uv_levels[j][i]);
- }
- printf("\n");
- }
-}
-
-#endif // DEBUG_BLOCK
-
-//------------------------------------------------------------------------------
-
-static WEBP_INLINE int clip(int v, int m, int M) {
- return v < m ? m : v > M ? M : v;
-}
-
-static const uint8_t kZigzag[16] = {
- 0, 1, 4, 8, 5, 2, 3, 6, 9, 12, 13, 10, 7, 11, 14, 15
-};
-
-static const uint8_t kDcTable[128] = {
- 4, 5, 6, 7, 8, 9, 10, 10,
- 11, 12, 13, 14, 15, 16, 17, 17,
- 18, 19, 20, 20, 21, 21, 22, 22,
- 23, 23, 24, 25, 25, 26, 27, 28,
- 29, 30, 31, 32, 33, 34, 35, 36,
- 37, 37, 38, 39, 40, 41, 42, 43,
- 44, 45, 46, 46, 47, 48, 49, 50,
- 51, 52, 53, 54, 55, 56, 57, 58,
- 59, 60, 61, 62, 63, 64, 65, 66,
- 67, 68, 69, 70, 71, 72, 73, 74,
- 75, 76, 76, 77, 78, 79, 80, 81,
- 82, 83, 84, 85, 86, 87, 88, 89,
- 91, 93, 95, 96, 98, 100, 101, 102,
- 104, 106, 108, 110, 112, 114, 116, 118,
- 122, 124, 126, 128, 130, 132, 134, 136,
- 138, 140, 143, 145, 148, 151, 154, 157
-};
-
-static const uint16_t kAcTable[128] = {
- 4, 5, 6, 7, 8, 9, 10, 11,
- 12, 13, 14, 15, 16, 17, 18, 19,
- 20, 21, 22, 23, 24, 25, 26, 27,
- 28, 29, 30, 31, 32, 33, 34, 35,
- 36, 37, 38, 39, 40, 41, 42, 43,
- 44, 45, 46, 47, 48, 49, 50, 51,
- 52, 53, 54, 55, 56, 57, 58, 60,
- 62, 64, 66, 68, 70, 72, 74, 76,
- 78, 80, 82, 84, 86, 88, 90, 92,
- 94, 96, 98, 100, 102, 104, 106, 108,
- 110, 112, 114, 116, 119, 122, 125, 128,
- 131, 134, 137, 140, 143, 146, 149, 152,
- 155, 158, 161, 164, 167, 170, 173, 177,
- 181, 185, 189, 193, 197, 201, 205, 209,
- 213, 217, 221, 225, 229, 234, 239, 245,
- 249, 254, 259, 264, 269, 274, 279, 284
-};
-
-static const uint16_t kAcTable2[128] = {
- 8, 8, 9, 10, 12, 13, 15, 17,
- 18, 20, 21, 23, 24, 26, 27, 29,
- 31, 32, 34, 35, 37, 38, 40, 41,
- 43, 44, 46, 48, 49, 51, 52, 54,
- 55, 57, 58, 60, 62, 63, 65, 66,
- 68, 69, 71, 72, 74, 75, 77, 79,
- 80, 82, 83, 85, 86, 88, 89, 93,
- 96, 99, 102, 105, 108, 111, 114, 117,
- 120, 124, 127, 130, 133, 136, 139, 142,
- 145, 148, 151, 155, 158, 161, 164, 167,
- 170, 173, 176, 179, 184, 189, 193, 198,
- 203, 207, 212, 217, 221, 226, 230, 235,
- 240, 244, 249, 254, 258, 263, 268, 274,
- 280, 286, 292, 299, 305, 311, 317, 323,
- 330, 336, 342, 348, 354, 362, 370, 379,
- 385, 393, 401, 409, 416, 424, 432, 440
-};
-
-static const uint8_t kBiasMatrices[3][2] = { // [luma-ac,luma-dc,chroma][dc,ac]
- { 96, 110 }, { 96, 108 }, { 110, 115 }
-};
-
-// Sharpening by (slightly) raising the hi-frequency coeffs.
-// Hack-ish but helpful for mid-bitrate range. Use with care.
-#define SHARPEN_BITS 11 // number of descaling bits for sharpening bias
-static const uint8_t kFreqSharpening[16] = {
- 0, 30, 60, 90,
- 30, 60, 90, 90,
- 60, 90, 90, 90,
- 90, 90, 90, 90
-};
-
-//------------------------------------------------------------------------------
-// Initialize quantization parameters in VP8Matrix
-
-// Returns the average quantizer
-static int ExpandMatrix(VP8Matrix* const m, int type) {
- int i, sum;
- for (i = 0; i < 2; ++i) {
- const int is_ac_coeff = (i > 0);
- const int bias = kBiasMatrices[type][is_ac_coeff];
- m->iq_[i] = (1 << QFIX) / m->q_[i];
- m->bias_[i] = BIAS(bias);
- // zthresh_ is the exact value such that QUANTDIV(coeff, iQ, B) is:
- // * zero if coeff <= zthresh
- // * non-zero if coeff > zthresh
- m->zthresh_[i] = ((1 << QFIX) - 1 - m->bias_[i]) / m->iq_[i];
- }
- for (i = 2; i < 16; ++i) {
- m->q_[i] = m->q_[1];
- m->iq_[i] = m->iq_[1];
- m->bias_[i] = m->bias_[1];
- m->zthresh_[i] = m->zthresh_[1];
- }
- for (sum = 0, i = 0; i < 16; ++i) {
- if (type == 0) { // we only use sharpening for AC luma coeffs
- m->sharpen_[i] = (kFreqSharpening[i] * m->q_[i]) >> SHARPEN_BITS;
- } else {
- m->sharpen_[i] = 0;
- }
- sum += m->q_[i];
- }
- return (sum + 8) >> 4;
-}
-
-static void CheckLambdaValue(int* const v) { if (*v < 1) *v = 1; }
-
-static void SetupMatrices(VP8Encoder* enc) {
- int i;
- const int tlambda_scale =
- (enc->method_ >= 4) ? enc->config_->sns_strength
- : 0;
- const int num_segments = enc->segment_hdr_.num_segments_;
- for (i = 0; i < num_segments; ++i) {
- VP8SegmentInfo* const m = &enc->dqm_[i];
- const int q = m->quant_;
- int q_i4, q_i16, q_uv;
- m->y1_.q_[0] = kDcTable[clip(q + enc->dq_y1_dc_, 0, 127)];
- m->y1_.q_[1] = kAcTable[clip(q, 0, 127)];
-
- m->y2_.q_[0] = kDcTable[ clip(q + enc->dq_y2_dc_, 0, 127)] * 2;
- m->y2_.q_[1] = kAcTable2[clip(q + enc->dq_y2_ac_, 0, 127)];
-
- m->uv_.q_[0] = kDcTable[clip(q + enc->dq_uv_dc_, 0, 117)];
- m->uv_.q_[1] = kAcTable[clip(q + enc->dq_uv_ac_, 0, 127)];
-
- q_i4 = ExpandMatrix(&m->y1_, 0);
- q_i16 = ExpandMatrix(&m->y2_, 1);
- q_uv = ExpandMatrix(&m->uv_, 2);
-
- m->lambda_i4_ = (3 * q_i4 * q_i4) >> 7;
- m->lambda_i16_ = (3 * q_i16 * q_i16);
- m->lambda_uv_ = (3 * q_uv * q_uv) >> 6;
- m->lambda_mode_ = (1 * q_i4 * q_i4) >> 7;
- m->lambda_trellis_i4_ = (7 * q_i4 * q_i4) >> 3;
- m->lambda_trellis_i16_ = (q_i16 * q_i16) >> 2;
- m->lambda_trellis_uv_ = (q_uv * q_uv) << 1;
- m->tlambda_ = (tlambda_scale * q_i4) >> 5;
-
- // none of these constants should be < 1
- CheckLambdaValue(&m->lambda_i4_);
- CheckLambdaValue(&m->lambda_i16_);
- CheckLambdaValue(&m->lambda_uv_);
- CheckLambdaValue(&m->lambda_mode_);
- CheckLambdaValue(&m->lambda_trellis_i4_);
- CheckLambdaValue(&m->lambda_trellis_i16_);
- CheckLambdaValue(&m->lambda_trellis_uv_);
- CheckLambdaValue(&m->tlambda_);
-
- m->min_disto_ = 20 * m->y1_.q_[0]; // quantization-aware min disto
- m->max_edge_ = 0;
-
- m->i4_penalty_ = 1000 * q_i4 * q_i4;
- }
-}
-
-//------------------------------------------------------------------------------
-// Initialize filtering parameters
-
-// Very small filter-strength values have close to no visual effect. So we can
-// save a little decoding-CPU by turning filtering off for these.
-#define FSTRENGTH_CUTOFF 2
-
-static void SetupFilterStrength(VP8Encoder* const enc) {
- int i;
- // level0 is in [0..500]. Using '-f 50' as filter_strength is mid-filtering.
- const int level0 = 5 * enc->config_->filter_strength;
- for (i = 0; i < NUM_MB_SEGMENTS; ++i) {
- VP8SegmentInfo* const m = &enc->dqm_[i];
- // We focus on the quantization of AC coeffs.
- const int qstep = kAcTable[clip(m->quant_, 0, 127)] >> 2;
- const int base_strength =
- VP8FilterStrengthFromDelta(enc->filter_hdr_.sharpness_, qstep);
- // Segments with lower complexity ('beta') will be less filtered.
- const int f = base_strength * level0 / (256 + m->beta_);
- m->fstrength_ = (f < FSTRENGTH_CUTOFF) ? 0 : (f > 63) ? 63 : f;
- }
- // We record the initial strength (mainly for the case of 1-segment only).
- enc->filter_hdr_.level_ = enc->dqm_[0].fstrength_;
- enc->filter_hdr_.simple_ = (enc->config_->filter_type == 0);
- enc->filter_hdr_.sharpness_ = enc->config_->filter_sharpness;
-}
-
-//------------------------------------------------------------------------------
-
-// Note: if you change the values below, remember that the max range
-// allowed by the syntax for DQ_UV is [-16,16].
-#define MAX_DQ_UV (6)
-#define MIN_DQ_UV (-4)
-
-// We want to emulate jpeg-like behaviour where the expected "good" quality
-// is around q=75. Internally, our "good" middle is around c=50. So we
-// map accordingly using linear piece-wise function
-static double QualityToCompression(double c) {
- const double linear_c = (c < 0.75) ? c * (2. / 3.) : 2. * c - 1.;
- // The file size roughly scales as pow(quantizer, 3.). Actually, the
- // exponent is somewhere between 2.8 and 3.2, but we're mostly interested
- // in the mid-quant range. So we scale the compressibility inversely to
- // this power-law: quant ~= compression ^ 1/3. This law holds well for
- // low quant. Finer modeling for high-quant would make use of kAcTable[]
- // more explicitly.
- const double v = pow(linear_c, 1 / 3.);
- return v;
-}
-
-static double QualityToJPEGCompression(double c, double alpha) {
- // We map the complexity 'alpha' and quality setting 'c' to a compression
- // exponent empirically matched to the compression curve of libjpeg6b.
- // On average, the WebP output size will be roughly similar to that of a
- // JPEG file compressed with same quality factor.
- const double amin = 0.30;
- const double amax = 0.85;
- const double exp_min = 0.4;
- const double exp_max = 0.9;
- const double slope = (exp_min - exp_max) / (amax - amin);
- // Linearly interpolate 'expn' from exp_min to exp_max
- // in the [amin, amax] range.
- const double expn = (alpha > amax) ? exp_min
- : (alpha < amin) ? exp_max
- : exp_max + slope * (alpha - amin);
- const double v = pow(c, expn);
- return v;
-}
-
-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 };
- // 'num_segments_' is previously validated and <= NUM_MB_SEGMENTS, but an
- // explicit check is needed to avoid a spurious warning about 'i' exceeding
- // array bounds of 'dqm_' with some compilers (noticed with gcc-4.9).
- const int num_segments = (enc->segment_hdr_.num_segments_ < NUM_MB_SEGMENTS)
- ? enc->segment_hdr_.num_segments_
- : NUM_MB_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->segment_hdr_.num_segments_;
- const double amp = SNS_TO_DQ * enc->config_->sns_strength / 100. / 128.;
- const double Q = quality / 100.;
- const double c_base = enc->config_->emulate_jpeg_size ?
- QualityToJPEGCompression(Q, enc->alpha_ / 255.) :
- QualityToCompression(Q);
- for (i = 0; i < num_segments; ++i) {
- // We modulate the base coefficient to accommodate for the quantization
- // susceptibility and allow denser segments to be quantized more.
- const double expn = 1. - amp * enc->dqm_[i].alpha_;
- const double c = pow(c_base, expn);
- const int q = (int)(127. * (1. - c));
- assert(expn > 0.);
- enc->dqm_[i].quant_ = clip(q, 0, 127);
- }
-
- // purely indicative in the bitstream (except for the 1-segment case)
- enc->base_quant_ = enc->dqm_[0].quant_;
-
- // fill-in values for the unused segments (required by the syntax)
- for (i = num_segments; i < NUM_MB_SEGMENTS; ++i) {
- enc->dqm_[i].quant_ = enc->base_quant_;
- }
-
- // uv_alpha_ is normally spread around ~60. The useful range is
- // typically ~30 (quite bad) to ~100 (ok to decimate UV more).
- // We map it to the safe maximal range of MAX/MIN_DQ_UV for dq_uv.
- dq_uv_ac = (enc->uv_alpha_ - MID_ALPHA) * (MAX_DQ_UV - MIN_DQ_UV)
- / (MAX_ALPHA - MIN_ALPHA);
- // we rescale by the user-defined strength of adaptation
- dq_uv_ac = dq_uv_ac * enc->config_->sns_strength / 100;
- // and make it safe.
- dq_uv_ac = clip(dq_uv_ac, MIN_DQ_UV, MAX_DQ_UV);
- // We also boost the dc-uv-quant a little, based on sns-strength, since
- // U/V channels are quite more reactive to high quants (flat DC-blocks
- // tend to appear, and are unpleasant).
- dq_uv_dc = -4 * enc->config_->sns_strength / 100;
- dq_uv_dc = clip(dq_uv_dc, -15, 15); // 4bit-signed max allowed
-
- enc->dq_y1_dc_ = 0; // TODO(skal): dq-lum
- enc->dq_y2_dc_ = 0;
- enc->dq_y2_ac_ = 0;
- enc->dq_uv_dc_ = dq_uv_dc;
- enc->dq_uv_ac_ = dq_uv_ac;
-
- SetupFilterStrength(enc); // initialize segments' filtering, eventually
-
- if (num_segments > 1) SimplifySegments(enc);
-
- SetupMatrices(enc); // finalize quantization matrices
-}
-
-//------------------------------------------------------------------------------
-// Form the predictions in cache
-
-// Must be ordered using {DC_PRED, TM_PRED, V_PRED, H_PRED} as index
-const int VP8I16ModeOffsets[4] = { I16DC16, I16TM16, I16VE16, I16HE16 };
-const int VP8UVModeOffsets[4] = { C8DC8, C8TM8, C8VE8, C8HE8 };
-
-// Must be indexed using {B_DC_PRED -> B_HU_PRED} as index
-const int VP8I4ModeOffsets[NUM_BMODES] = {
- I4DC4, I4TM4, I4VE4, I4HE4, I4RD4, I4VR4, I4LD4, I4VL4, I4HD4, I4HU4
-};
-
-void VP8MakeLuma16Preds(const VP8EncIterator* const it) {
- const uint8_t* const left = it->x_ ? it->y_left_ : NULL;
- const uint8_t* const top = it->y_ ? it->y_top_ : NULL;
- VP8EncPredLuma16(it->yuv_p_, left, top);
-}
-
-void VP8MakeChroma8Preds(const VP8EncIterator* const it) {
- const uint8_t* const left = it->x_ ? it->u_left_ : NULL;
- const uint8_t* const top = it->y_ ? it->uv_top_ : NULL;
- VP8EncPredChroma8(it->yuv_p_, left, top);
-}
-
-void VP8MakeIntra4Preds(const VP8EncIterator* const it) {
- VP8EncPredLuma4(it->yuv_p_, it->i4_top_);
-}
-
-//------------------------------------------------------------------------------
-// Quantize
-
-// Layout:
-// +----+----+
-// |YYYY|UUVV| 0
-// |YYYY|UUVV| 4
-// |YYYY|....| 8
-// |YYYY|....| 12
-// +----+----+
-
-const int VP8Scan[16] = { // Luma
- 0 + 0 * BPS, 4 + 0 * BPS, 8 + 0 * BPS, 12 + 0 * BPS,
- 0 + 4 * BPS, 4 + 4 * BPS, 8 + 4 * BPS, 12 + 4 * BPS,
- 0 + 8 * BPS, 4 + 8 * BPS, 8 + 8 * BPS, 12 + 8 * BPS,
- 0 + 12 * BPS, 4 + 12 * BPS, 8 + 12 * BPS, 12 + 12 * BPS,
-};
-
-static const int VP8ScanUV[4 + 4] = {
- 0 + 0 * BPS, 4 + 0 * BPS, 0 + 4 * BPS, 4 + 4 * BPS, // U
- 8 + 0 * BPS, 12 + 0 * BPS, 8 + 4 * BPS, 12 + 4 * BPS // V
-};
-
-//------------------------------------------------------------------------------
-// Distortion measurement
-
-static const uint16_t kWeightY[16] = {
- 38, 32, 20, 9, 32, 28, 17, 7, 20, 17, 10, 4, 9, 7, 4, 2
-};
-
-static const uint16_t kWeightTrellis[16] = {
-#if USE_TDISTO == 0
- 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16
-#else
- 30, 27, 19, 11,
- 27, 24, 17, 10,
- 19, 17, 12, 8,
- 11, 10, 8, 6
-#endif
-};
-
-// Init/Copy the common fields in score.
-static void InitScore(VP8ModeScore* const rd) {
- rd->D = 0;
- rd->SD = 0;
- rd->R = 0;
- rd->H = 0;
- rd->nz = 0;
- rd->score = MAX_COST;
-}
-
-static void CopyScore(VP8ModeScore* const dst, const VP8ModeScore* const src) {
- dst->D = src->D;
- dst->SD = src->SD;
- dst->R = src->R;
- dst->H = src->H;
- dst->nz = src->nz; // note that nz is not accumulated, but just copied.
- dst->score = src->score;
-}
-
-static void AddScore(VP8ModeScore* const dst, const VP8ModeScore* const src) {
- dst->D += src->D;
- dst->SD += src->SD;
- dst->R += src->R;
- dst->H += src->H;
- dst->nz |= src->nz; // here, new nz bits are accumulated.
- dst->score += src->score;
-}
-
-//------------------------------------------------------------------------------
-// Performs trellis-optimized quantization.
-
-// Trellis node
-typedef struct {
- int8_t prev; // best previous node
- int8_t sign; // sign of coeff_i
- int16_t level; // level
-} Node;
-
-// Score state
-typedef struct {
- score_t score; // partial RD score
- const uint16_t* costs; // shortcut to cost tables
-} ScoreState;
-
-// If a coefficient was quantized to a value Q (using a neutral bias),
-// we test all alternate possibilities between [Q-MIN_DELTA, Q+MAX_DELTA]
-// We don't test negative values though.
-#define MIN_DELTA 0 // how much lower level to try
-#define MAX_DELTA 1 // how much higher
-#define NUM_NODES (MIN_DELTA + 1 + MAX_DELTA)
-#define NODE(n, l) (nodes[(n)][(l) + MIN_DELTA])
-#define SCORE_STATE(n, l) (score_states[n][(l) + MIN_DELTA])
-
-static WEBP_INLINE void SetRDScore(int lambda, VP8ModeScore* const rd) {
- rd->score = (rd->R + rd->H) * lambda + RD_DISTO_MULT * (rd->D + rd->SD);
-}
-
-static WEBP_INLINE score_t RDScoreTrellis(int lambda, score_t rate,
- score_t distortion) {
- return rate * lambda + RD_DISTO_MULT * distortion;
-}
-
-static int TrellisQuantizeBlock(const VP8Encoder* const enc,
- int16_t in[16], int16_t out[16],
- int ctx0, int coeff_type,
- const VP8Matrix* const mtx,
- int lambda) {
- const ProbaArray* const probas = enc->proba_.coeffs_[coeff_type];
- CostArrayPtr const costs =
- (CostArrayPtr)enc->proba_.remapped_costs_[coeff_type];
- const int first = (coeff_type == 0) ? 1 : 0;
- Node nodes[16][NUM_NODES];
- ScoreState score_states[2][NUM_NODES];
- ScoreState* ss_cur = &SCORE_STATE(0, MIN_DELTA);
- ScoreState* ss_prev = &SCORE_STATE(1, MIN_DELTA);
- int best_path[3] = {-1, -1, -1}; // store best-last/best-level/best-previous
- score_t best_score;
- int n, m, p, last;
-
- {
- score_t cost;
- const int thresh = mtx->q_[1] * mtx->q_[1] / 4;
- const int last_proba = probas[VP8EncBands[first]][ctx0][0];
-
- // compute the position of the last interesting coefficient
- last = first - 1;
- for (n = 15; n >= first; --n) {
- const int j = kZigzag[n];
- const int err = in[j] * in[j];
- if (err > thresh) {
- last = n;
- break;
- }
- }
- // we don't need to go inspect up to n = 16 coeffs. We can just go up
- // to last + 1 (inclusive) without losing much.
- if (last < 15) ++last;
-
- // compute 'skip' score. This is the max score one can do.
- cost = VP8BitCost(0, last_proba);
- best_score = RDScoreTrellis(lambda, cost, 0);
-
- // initialize source node.
- for (m = -MIN_DELTA; m <= MAX_DELTA; ++m) {
- const score_t rate = (ctx0 == 0) ? VP8BitCost(1, last_proba) : 0;
- ss_cur[m].score = RDScoreTrellis(lambda, rate, 0);
- ss_cur[m].costs = costs[first][ctx0];
- }
- }
-
- // traverse trellis.
- for (n = first; n <= last; ++n) {
- const int j = kZigzag[n];
- const uint32_t Q = mtx->q_[j];
- const uint32_t iQ = mtx->iq_[j];
- const uint32_t B = BIAS(0x00); // neutral bias
- // note: it's important to take sign of the _original_ coeff,
- // so we don't have to consider level < 0 afterward.
- const int sign = (in[j] < 0);
- const uint32_t coeff0 = (sign ? -in[j] : in[j]) + mtx->sharpen_[j];
- int level0 = QUANTDIV(coeff0, iQ, B);
- if (level0 > MAX_LEVEL) level0 = MAX_LEVEL;
-
- { // Swap current and previous score states
- ScoreState* const tmp = ss_cur;
- ss_cur = ss_prev;
- ss_prev = tmp;
- }
-
- // test all alternate level values around level0.
- for (m = -MIN_DELTA; m <= MAX_DELTA; ++m) {
- Node* const cur = &NODE(n, m);
- int level = level0 + m;
- const int ctx = (level > 2) ? 2 : level;
- const int band = VP8EncBands[n + 1];
- score_t base_score, last_pos_score;
- score_t best_cur_score = MAX_COST;
- int best_prev = 0; // default, in case
-
- ss_cur[m].score = MAX_COST;
- ss_cur[m].costs = costs[n + 1][ctx];
- if (level > MAX_LEVEL || level < 0) { // node is dead?
- continue;
- }
-
- // Compute extra rate cost if last coeff's position is < 15
- {
- const score_t last_pos_cost =
- (n < 15) ? VP8BitCost(0, probas[band][ctx][0]) : 0;
- last_pos_score = RDScoreTrellis(lambda, last_pos_cost, 0);
- }
-
- {
- // Compute delta_error = how much coding this level will
- // subtract to max_error as distortion.
- // Here, distortion = sum of (|coeff_i| - level_i * Q_i)^2
- const int new_error = coeff0 - level * Q;
- const int delta_error =
- kWeightTrellis[j] * (new_error * new_error - coeff0 * coeff0);
- base_score = RDScoreTrellis(lambda, 0, delta_error);
- }
-
- // Inspect all possible non-dead predecessors. Retain only the best one.
- for (p = -MIN_DELTA; p <= MAX_DELTA; ++p) {
- // Dead nodes (with ss_prev[p].score >= MAX_COST) are automatically
- // eliminated since their score can't be better than the current best.
- const score_t cost = VP8LevelCost(ss_prev[p].costs, level);
- // Examine node assuming it's a non-terminal one.
- const score_t score =
- base_score + ss_prev[p].score + RDScoreTrellis(lambda, cost, 0);
- if (score < best_cur_score) {
- best_cur_score = score;
- best_prev = p;
- }
- }
- // Store best finding in current node.
- cur->sign = sign;
- cur->level = level;
- cur->prev = best_prev;
- ss_cur[m].score = best_cur_score;
-
- // Now, record best terminal node (and thus best entry in the graph).
- if (level != 0) {
- const score_t score = best_cur_score + last_pos_score;
- if (score < best_score) {
- best_score = score;
- best_path[0] = n; // best eob position
- best_path[1] = m; // best node index
- best_path[2] = best_prev; // best predecessor
- }
- }
- }
- }
-
- // Fresh start
- memset(in + first, 0, (16 - first) * sizeof(*in));
- memset(out + first, 0, (16 - first) * sizeof(*out));
- if (best_path[0] == -1) {
- return 0; // skip!
- }
-
- {
- // Unwind the best path.
- // Note: best-prev on terminal node is not necessarily equal to the
- // best_prev for non-terminal. So we patch best_path[2] in.
- int nz = 0;
- int best_node = best_path[1];
- n = best_path[0];
- NODE(n, best_node).prev = best_path[2]; // force best-prev for terminal
-
- for (; n >= first; --n) {
- const Node* const node = &NODE(n, best_node);
- const int j = kZigzag[n];
- out[n] = node->sign ? -node->level : node->level;
- nz |= node->level;
- in[j] = out[n] * mtx->q_[j];
- best_node = node->prev;
- }
- return (nz != 0);
- }
-}
-
-#undef NODE
-
-//------------------------------------------------------------------------------
-// Performs: difference, transform, quantize, back-transform, add
-// all at once. Output is the reconstructed block in *yuv_out, and the
-// quantized levels in *levels.
-
-static int ReconstructIntra16(VP8EncIterator* const it,
- VP8ModeScore* const rd,
- uint8_t* const yuv_out,
- int mode) {
- const VP8Encoder* const enc = it->enc_;
- const uint8_t* const ref = it->yuv_p_ + VP8I16ModeOffsets[mode];
- const uint8_t* const src = it->yuv_in_ + Y_OFF_ENC;
- const VP8SegmentInfo* const dqm = &enc->dqm_[it->mb_->segment_];
- int nz = 0;
- int n;
- int16_t tmp[16][16], dc_tmp[16];
-
- for (n = 0; n < 16; n += 2) {
- VP8FTransform2(src + VP8Scan[n], ref + VP8Scan[n], tmp[n]);
- }
- VP8FTransformWHT(tmp[0], dc_tmp);
- nz |= VP8EncQuantizeBlockWHT(dc_tmp, rd->y_dc_levels, &dqm->y2_) << 24;
-
- if (DO_TRELLIS_I16 && it->do_trellis_) {
- int x, y;
- VP8IteratorNzToBytes(it);
- for (y = 0, n = 0; y < 4; ++y) {
- for (x = 0; x < 4; ++x, ++n) {
- const int ctx = it->top_nz_[x] + it->left_nz_[y];
- const int non_zero =
- TrellisQuantizeBlock(enc, tmp[n], rd->y_ac_levels[n], ctx, 0,
- &dqm->y1_, dqm->lambda_trellis_i16_);
- it->top_nz_[x] = it->left_nz_[y] = non_zero;
- rd->y_ac_levels[n][0] = 0;
- nz |= non_zero << n;
- }
- }
- } else {
- for (n = 0; n < 16; n += 2) {
- // Zero-out the first coeff, so that: a) nz is correct below, and
- // b) finding 'last' non-zero coeffs in SetResidualCoeffs() is simplified.
- tmp[n][0] = tmp[n + 1][0] = 0;
- nz |= VP8EncQuantize2Blocks(tmp[n], rd->y_ac_levels[n], &dqm->y1_) << n;
- assert(rd->y_ac_levels[n + 0][0] == 0);
- assert(rd->y_ac_levels[n + 1][0] == 0);
- }
- }
-
- // Transform back
- VP8TransformWHT(dc_tmp, tmp[0]);
- for (n = 0; n < 16; n += 2) {
- VP8ITransform(ref + VP8Scan[n], tmp[n], yuv_out + VP8Scan[n], 1);
- }
-
- return nz;
-}
-
-static int ReconstructIntra4(VP8EncIterator* const it,
- int16_t levels[16],
- const uint8_t* const src,
- uint8_t* const yuv_out,
- int mode) {
- const VP8Encoder* const enc = it->enc_;
- const uint8_t* const ref = it->yuv_p_ + VP8I4ModeOffsets[mode];
- const VP8SegmentInfo* const dqm = &enc->dqm_[it->mb_->segment_];
- int nz = 0;
- int16_t tmp[16];
-
- VP8FTransform(src, ref, tmp);
- if (DO_TRELLIS_I4 && it->do_trellis_) {
- const int x = it->i4_ & 3, y = it->i4_ >> 2;
- const int ctx = it->top_nz_[x] + it->left_nz_[y];
- nz = TrellisQuantizeBlock(enc, tmp, levels, ctx, 3, &dqm->y1_,
- dqm->lambda_trellis_i4_);
- } else {
- nz = VP8EncQuantizeBlock(tmp, levels, &dqm->y1_);
- }
- VP8ITransform(ref, tmp, yuv_out, 0);
- return nz;
-}
-
-static int ReconstructUV(VP8EncIterator* const it, VP8ModeScore* const rd,
- uint8_t* const yuv_out, int mode) {
- const VP8Encoder* const enc = it->enc_;
- const uint8_t* const ref = it->yuv_p_ + VP8UVModeOffsets[mode];
- const uint8_t* const src = it->yuv_in_ + U_OFF_ENC;
- const VP8SegmentInfo* const dqm = &enc->dqm_[it->mb_->segment_];
- int nz = 0;
- int n;
- int16_t tmp[8][16];
-
- for (n = 0; n < 8; n += 2) {
- VP8FTransform2(src + VP8ScanUV[n], ref + VP8ScanUV[n], tmp[n]);
- }
- if (DO_TRELLIS_UV && it->do_trellis_) {
- int ch, x, y;
- for (ch = 0, n = 0; ch <= 2; ch += 2) {
- for (y = 0; y < 2; ++y) {
- for (x = 0; x < 2; ++x, ++n) {
- const int ctx = it->top_nz_[4 + ch + x] + it->left_nz_[4 + ch + y];
- const int non_zero =
- TrellisQuantizeBlock(enc, tmp[n], rd->uv_levels[n], ctx, 2,
- &dqm->uv_, dqm->lambda_trellis_uv_);
- it->top_nz_[4 + ch + x] = it->left_nz_[4 + ch + y] = non_zero;
- nz |= non_zero << n;
- }
- }
- }
- } else {
- for (n = 0; n < 8; n += 2) {
- nz |= VP8EncQuantize2Blocks(tmp[n], rd->uv_levels[n], &dqm->uv_) << n;
- }
- }
-
- for (n = 0; n < 8; n += 2) {
- VP8ITransform(ref + VP8ScanUV[n], tmp[n], yuv_out + VP8ScanUV[n], 1);
- }
- return (nz << 16);
-}
-
-//------------------------------------------------------------------------------
-// RD-opt decision. Reconstruct each modes, evalue distortion and bit-cost.
-// Pick the mode is lower RD-cost = Rate + lambda * Distortion.
-
-static void StoreMaxDelta(VP8SegmentInfo* const dqm, const int16_t DCs[16]) {
- // We look at the first three AC coefficients to determine what is the average
- // delta between each sub-4x4 block.
- const int v0 = abs(DCs[1]);
- const int v1 = abs(DCs[2]);
- const int v2 = abs(DCs[4]);
- int max_v = (v1 > v0) ? v1 : v0;
- max_v = (v2 > max_v) ? v2 : max_v;
- if (max_v > dqm->max_edge_) dqm->max_edge_ = max_v;
-}
-
-static void SwapModeScore(VP8ModeScore** a, VP8ModeScore** b) {
- VP8ModeScore* const tmp = *a;
- *a = *b;
- *b = tmp;
-}
-
-static void SwapPtr(uint8_t** a, uint8_t** b) {
- uint8_t* const tmp = *a;
- *a = *b;
- *b = tmp;
-}
-
-static void SwapOut(VP8EncIterator* const it) {
- SwapPtr(&it->yuv_out_, &it->yuv_out2_);
-}
-
-static score_t IsFlat(const int16_t* levels, int num_blocks, score_t thresh) {
- score_t score = 0;
- while (num_blocks-- > 0) { // TODO(skal): refine positional scoring?
- int i;
- for (i = 1; i < 16; ++i) { // omit DC, we're only interested in AC
- score += (levels[i] != 0);
- if (score > thresh) return 0;
- }
- levels += 16;
- }
- return 1;
-}
-
-static void PickBestIntra16(VP8EncIterator* const it, VP8ModeScore* rd) {
- const int kNumBlocks = 16;
- VP8SegmentInfo* const dqm = &it->enc_->dqm_[it->mb_->segment_];
- const int lambda = dqm->lambda_i16_;
- const int tlambda = dqm->tlambda_;
- const uint8_t* const src = it->yuv_in_ + Y_OFF_ENC;
- VP8ModeScore rd_tmp;
- VP8ModeScore* rd_cur = &rd_tmp;
- VP8ModeScore* rd_best = rd;
- int mode;
-
- rd->mode_i16 = -1;
- for (mode = 0; mode < NUM_PRED_MODES; ++mode) {
- uint8_t* const tmp_dst = it->yuv_out2_ + Y_OFF_ENC; // scratch buffer
- rd_cur->mode_i16 = mode;
-
- // Reconstruct
- rd_cur->nz = ReconstructIntra16(it, rd_cur, tmp_dst, mode);
-
- // Measure RD-score
- rd_cur->D = VP8SSE16x16(src, tmp_dst);
- rd_cur->SD =
- tlambda ? MULT_8B(tlambda, VP8TDisto16x16(src, tmp_dst, kWeightY)) : 0;
- rd_cur->H = VP8FixedCostsI16[mode];
- rd_cur->R = VP8GetCostLuma16(it, rd_cur);
- if (mode > 0 &&
- IsFlat(rd_cur->y_ac_levels[0], kNumBlocks, FLATNESS_LIMIT_I16)) {
- // penalty to avoid flat area to be mispredicted by complex mode
- rd_cur->R += FLATNESS_PENALTY * kNumBlocks;
- }
-
- // Since we always examine Intra16 first, we can overwrite *rd directly.
- SetRDScore(lambda, rd_cur);
- if (mode == 0 || rd_cur->score < rd_best->score) {
- SwapModeScore(&rd_cur, &rd_best);
- SwapOut(it);
- }
- }
- if (rd_best != rd) {
- memcpy(rd, rd_best, sizeof(*rd));
- }
- SetRDScore(dqm->lambda_mode_, rd); // finalize score for mode decision.
- VP8SetIntra16Mode(it, rd->mode_i16);
-
- // we have a blocky macroblock (only DCs are non-zero) with fairly high
- // distortion, record max delta so we can later adjust the minimal filtering
- // strength needed to smooth these blocks out.
- if ((rd->nz & 0x100ffff) == 0x1000000 && rd->D > dqm->min_disto_) {
- StoreMaxDelta(dqm, rd->y_dc_levels);
- }
-}
-
-//------------------------------------------------------------------------------
-
-// return the cost array corresponding to the surrounding prediction modes.
-static const uint16_t* GetCostModeI4(VP8EncIterator* const it,
- const uint8_t modes[16]) {
- const int preds_w = it->enc_->preds_w_;
- const int x = (it->i4_ & 3), y = it->i4_ >> 2;
- const int left = (x == 0) ? it->preds_[y * preds_w - 1] : modes[it->i4_ - 1];
- const int top = (y == 0) ? it->preds_[-preds_w + x] : modes[it->i4_ - 4];
- return VP8FixedCostsI4[top][left];
-}
-
-static int PickBestIntra4(VP8EncIterator* const it, VP8ModeScore* const rd) {
- const VP8Encoder* const enc = it->enc_;
- const VP8SegmentInfo* const dqm = &enc->dqm_[it->mb_->segment_];
- const int lambda = dqm->lambda_i4_;
- const int tlambda = dqm->tlambda_;
- const uint8_t* const src0 = it->yuv_in_ + Y_OFF_ENC;
- uint8_t* const best_blocks = it->yuv_out2_ + Y_OFF_ENC;
- int total_header_bits = 0;
- VP8ModeScore rd_best;
-
- if (enc->max_i4_header_bits_ == 0) {
- return 0;
- }
-
- InitScore(&rd_best);
- rd_best.H = 211; // '211' is the value of VP8BitCost(0, 145)
- SetRDScore(dqm->lambda_mode_, &rd_best);
- VP8IteratorStartI4(it);
- do {
- const int kNumBlocks = 1;
- VP8ModeScore rd_i4;
- int mode;
- int best_mode = -1;
- const uint8_t* const src = src0 + VP8Scan[it->i4_];
- const uint16_t* const mode_costs = GetCostModeI4(it, rd->modes_i4);
- uint8_t* best_block = best_blocks + VP8Scan[it->i4_];
- uint8_t* tmp_dst = it->yuv_p_ + I4TMP; // scratch buffer.
-
- InitScore(&rd_i4);
- VP8MakeIntra4Preds(it);
- for (mode = 0; mode < NUM_BMODES; ++mode) {
- VP8ModeScore rd_tmp;
- int16_t tmp_levels[16];
-
- // Reconstruct
- rd_tmp.nz =
- ReconstructIntra4(it, tmp_levels, src, tmp_dst, mode) << it->i4_;
-
- // Compute RD-score
- rd_tmp.D = VP8SSE4x4(src, tmp_dst);
- rd_tmp.SD =
- tlambda ? MULT_8B(tlambda, VP8TDisto4x4(src, tmp_dst, kWeightY))
- : 0;
- rd_tmp.H = mode_costs[mode];
-
- // Add flatness penalty
- if (mode > 0 && IsFlat(tmp_levels, kNumBlocks, FLATNESS_LIMIT_I4)) {
- rd_tmp.R = FLATNESS_PENALTY * kNumBlocks;
- } else {
- rd_tmp.R = 0;
- }
-
- // early-out check
- SetRDScore(lambda, &rd_tmp);
- if (best_mode >= 0 && rd_tmp.score >= rd_i4.score) continue;
-
- // finish computing score
- rd_tmp.R += VP8GetCostLuma4(it, tmp_levels);
- SetRDScore(lambda, &rd_tmp);
-
- if (best_mode < 0 || rd_tmp.score < rd_i4.score) {
- CopyScore(&rd_i4, &rd_tmp);
- best_mode = mode;
- SwapPtr(&tmp_dst, &best_block);
- memcpy(rd_best.y_ac_levels[it->i4_], tmp_levels,
- sizeof(rd_best.y_ac_levels[it->i4_]));
- }
- }
- SetRDScore(dqm->lambda_mode_, &rd_i4);
- AddScore(&rd_best, &rd_i4);
- if (rd_best.score >= rd->score) {
- return 0;
- }
- total_header_bits += (int)rd_i4.H; // <- equal to mode_costs[best_mode];
- if (total_header_bits > enc->max_i4_header_bits_) {
- return 0;
- }
- // Copy selected samples if not in the right place already.
- if (best_block != best_blocks + VP8Scan[it->i4_]) {
- VP8Copy4x4(best_block, best_blocks + VP8Scan[it->i4_]);
- }
- rd->modes_i4[it->i4_] = best_mode;
- it->top_nz_[it->i4_ & 3] = it->left_nz_[it->i4_ >> 2] = (rd_i4.nz ? 1 : 0);
- } while (VP8IteratorRotateI4(it, best_blocks));
-
- // finalize state
- CopyScore(rd, &rd_best);
- VP8SetIntra4Mode(it, rd->modes_i4);
- SwapOut(it);
- memcpy(rd->y_ac_levels, rd_best.y_ac_levels, sizeof(rd->y_ac_levels));
- return 1; // select intra4x4 over intra16x16
-}
-
-//------------------------------------------------------------------------------
-
-static void PickBestUV(VP8EncIterator* const it, VP8ModeScore* const rd) {
- const int kNumBlocks = 8;
- const VP8SegmentInfo* const dqm = &it->enc_->dqm_[it->mb_->segment_];
- const int lambda = dqm->lambda_uv_;
- const uint8_t* const src = it->yuv_in_ + U_OFF_ENC;
- uint8_t* tmp_dst = it->yuv_out2_ + U_OFF_ENC; // scratch buffer
- uint8_t* dst0 = it->yuv_out_ + U_OFF_ENC;
- uint8_t* dst = dst0;
- VP8ModeScore rd_best;
- int mode;
-
- rd->mode_uv = -1;
- InitScore(&rd_best);
- for (mode = 0; mode < NUM_PRED_MODES; ++mode) {
- VP8ModeScore rd_uv;
-
- // Reconstruct
- rd_uv.nz = ReconstructUV(it, &rd_uv, tmp_dst, mode);
-
- // Compute RD-score
- rd_uv.D = VP8SSE16x8(src, tmp_dst);
- rd_uv.SD = 0; // not calling TDisto here: it tends to flatten areas.
- rd_uv.H = VP8FixedCostsUV[mode];
- rd_uv.R = VP8GetCostUV(it, &rd_uv);
- if (mode > 0 && IsFlat(rd_uv.uv_levels[0], kNumBlocks, FLATNESS_LIMIT_UV)) {
- rd_uv.R += FLATNESS_PENALTY * kNumBlocks;
- }
-
- SetRDScore(lambda, &rd_uv);
- if (mode == 0 || rd_uv.score < rd_best.score) {
- CopyScore(&rd_best, &rd_uv);
- rd->mode_uv = mode;
- memcpy(rd->uv_levels, rd_uv.uv_levels, sizeof(rd->uv_levels));
- SwapPtr(&dst, &tmp_dst);
- }
- }
- VP8SetIntraUVMode(it, rd->mode_uv);
- AddScore(rd, &rd_best);
- if (dst != dst0) { // copy 16x8 block if needed
- VP8Copy16x8(dst, dst0);
- }
-}
-
-//------------------------------------------------------------------------------
-// Final reconstruction and quantization.
-
-static void SimpleQuantize(VP8EncIterator* const it, VP8ModeScore* const rd) {
- const VP8Encoder* const enc = it->enc_;
- const int is_i16 = (it->mb_->type_ == 1);
- int nz = 0;
-
- if (is_i16) {
- nz = ReconstructIntra16(it, rd, it->yuv_out_ + Y_OFF_ENC, it->preds_[0]);
- } else {
- VP8IteratorStartI4(it);
- do {
- const int mode =
- it->preds_[(it->i4_ & 3) + (it->i4_ >> 2) * enc->preds_w_];
- const uint8_t* const src = it->yuv_in_ + Y_OFF_ENC + VP8Scan[it->i4_];
- uint8_t* const dst = it->yuv_out_ + Y_OFF_ENC + VP8Scan[it->i4_];
- VP8MakeIntra4Preds(it);
- nz |= ReconstructIntra4(it, rd->y_ac_levels[it->i4_],
- src, dst, mode) << it->i4_;
- } while (VP8IteratorRotateI4(it, it->yuv_out_ + Y_OFF_ENC));
- }
-
- nz |= ReconstructUV(it, rd, it->yuv_out_ + U_OFF_ENC, it->mb_->uv_mode_);
- rd->nz = nz;
-}
-
-// Refine intra16/intra4 sub-modes based on distortion only (not rate).
-static void RefineUsingDistortion(VP8EncIterator* const it,
- int try_both_modes, int refine_uv_mode,
- VP8ModeScore* const rd) {
- score_t best_score = MAX_COST;
- int nz = 0;
- int mode;
- int is_i16 = try_both_modes || (it->mb_->type_ == 1);
-
- const VP8SegmentInfo* const dqm = &it->enc_->dqm_[it->mb_->segment_];
- // Some empiric constants, of approximate order of magnitude.
- const int lambda_d_i16 = 106;
- const int lambda_d_i4 = 11;
- const int lambda_d_uv = 120;
- score_t score_i4 = dqm->i4_penalty_;
- score_t i4_bit_sum = 0;
- const score_t bit_limit = try_both_modes ? it->enc_->mb_header_limit_
- : MAX_COST; // no early-out allowed
-
- if (is_i16) { // First, evaluate Intra16 distortion
- int best_mode = -1;
- const uint8_t* const src = it->yuv_in_ + Y_OFF_ENC;
- for (mode = 0; mode < NUM_PRED_MODES; ++mode) {
- const uint8_t* const ref = it->yuv_p_ + VP8I16ModeOffsets[mode];
- const score_t score = VP8SSE16x16(src, ref) * RD_DISTO_MULT
- + VP8FixedCostsI16[mode] * lambda_d_i16;
- if (mode > 0 && VP8FixedCostsI16[mode] > bit_limit) {
- continue;
- }
- if (score < best_score) {
- best_mode = mode;
- best_score = score;
- }
- }
- VP8SetIntra16Mode(it, best_mode);
- // we'll reconstruct later, if i16 mode actually gets selected
- }
-
- // Next, evaluate Intra4
- if (try_both_modes || !is_i16) {
- // We don't evaluate the rate here, but just account for it through a
- // constant penalty (i4 mode usually needs more bits compared to i16).
- is_i16 = 0;
- VP8IteratorStartI4(it);
- do {
- int best_i4_mode = -1;
- score_t best_i4_score = MAX_COST;
- const uint8_t* const src = it->yuv_in_ + Y_OFF_ENC + VP8Scan[it->i4_];
- const uint16_t* const mode_costs = GetCostModeI4(it, rd->modes_i4);
-
- VP8MakeIntra4Preds(it);
- for (mode = 0; mode < NUM_BMODES; ++mode) {
- const uint8_t* const ref = it->yuv_p_ + VP8I4ModeOffsets[mode];
- const score_t score = VP8SSE4x4(src, ref) * RD_DISTO_MULT
- + mode_costs[mode] * lambda_d_i4;
- if (score < best_i4_score) {
- best_i4_mode = mode;
- best_i4_score = score;
- }
- }
- i4_bit_sum += mode_costs[best_i4_mode];
- rd->modes_i4[it->i4_] = best_i4_mode;
- score_i4 += best_i4_score;
- if (score_i4 >= best_score || i4_bit_sum > bit_limit) {
- // Intra4 won't be better than Intra16. Bail out and pick Intra16.
- is_i16 = 1;
- break;
- } else { // reconstruct partial block inside yuv_out2_ buffer
- uint8_t* const tmp_dst = it->yuv_out2_ + Y_OFF_ENC + VP8Scan[it->i4_];
- nz |= ReconstructIntra4(it, rd->y_ac_levels[it->i4_],
- src, tmp_dst, best_i4_mode) << it->i4_;
- }
- } while (VP8IteratorRotateI4(it, it->yuv_out2_ + Y_OFF_ENC));
- }
-
- // Final reconstruction, depending on which mode is selected.
- if (!is_i16) {
- VP8SetIntra4Mode(it, rd->modes_i4);
- SwapOut(it);
- best_score = score_i4;
- } else {
- nz = ReconstructIntra16(it, rd, it->yuv_out_ + Y_OFF_ENC, it->preds_[0]);
- }
-
- // ... and UV!
- if (refine_uv_mode) {
- int best_mode = -1;
- score_t best_uv_score = MAX_COST;
- const uint8_t* const src = it->yuv_in_ + U_OFF_ENC;
- for (mode = 0; mode < NUM_PRED_MODES; ++mode) {
- const uint8_t* const ref = it->yuv_p_ + VP8UVModeOffsets[mode];
- const score_t score = VP8SSE16x8(src, ref) * RD_DISTO_MULT
- + VP8FixedCostsUV[mode] * lambda_d_uv;
- if (score < best_uv_score) {
- best_mode = mode;
- best_uv_score = score;
- }
- }
- VP8SetIntraUVMode(it, best_mode);
- }
- nz |= ReconstructUV(it, rd, it->yuv_out_ + U_OFF_ENC, it->mb_->uv_mode_);
-
- rd->nz = nz;
- rd->score = best_score;
-}
-
-//------------------------------------------------------------------------------
-// Entry point
-
-int VP8Decimate(VP8EncIterator* const it, VP8ModeScore* const rd,
- VP8RDLevel rd_opt) {
- int is_skipped;
- const int method = it->enc_->method_;
-
- InitScore(rd);
-
- // We can perform predictions for Luma16x16 and Chroma8x8 already.
- // Luma4x4 predictions needs to be done as-we-go.
- VP8MakeLuma16Preds(it);
- VP8MakeChroma8Preds(it);
-
- if (rd_opt > RD_OPT_NONE) {
- it->do_trellis_ = (rd_opt >= RD_OPT_TRELLIS_ALL);
- PickBestIntra16(it, rd);
- if (method >= 2) {
- PickBestIntra4(it, rd);
- }
- PickBestUV(it, rd);
- if (rd_opt == RD_OPT_TRELLIS) { // finish off with trellis-optim now
- it->do_trellis_ = 1;
- SimpleQuantize(it, rd);
- }
- } else {
- // At this point we have heuristically decided intra16 / intra4.
- // For method >= 2, pick the best intra4/intra16 based on SSE (~tad slower).
- // For method <= 1, we don't re-examine the decision but just go ahead with
- // quantization/reconstruction.
- RefineUsingDistortion(it, (method >= 2), (method >= 1), rd);
- }
- is_skipped = (rd->nz == 0);
- VP8SetSkip(it, is_skipped);
- return is_skipped;
-}
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