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fix -m 2 mode-cost evaluation (causing partition0 overflow)

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The mode's bits were not taken into account, which is ok for most of cases.
But in case of super large image, with 'easy' content, their overhead starts
mattering a lot and we were omitting to optimize for these.
Now, these mode bits have their own lambda values associated, limiting
the jerkiness. We also limit (for -m 2 only) the individual number of bits
to something that will prevent the partition 0 overflow.

removed the I4_PENALTY constant, which was a rather crude approximation.
Replaced by some q-dependent expression.

fixes issue #289

Change-Id: I956ae2d2308c339adc4706d52722f0bb61ccf18c
This commit is contained in:
Pascal Massimino 2016-03-11 20:34:45 +01:00
parent 4562e83dc2
commit e88c4ca013
3 changed files with 58 additions and 25 deletions
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75
src/enc/quant.c
View File

@ -30,8 +30,6 @@
#define SNS_TO_DQ 0.9 // Scaling constant between the sns value and the QP
// power-law modulation. Must be strictly less than 1.
#define I4_PENALTY 14000 // Rate-penalty for quick i4/i16 decision
// 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
@ -236,6 +234,8 @@ static int ExpandMatrix(VP8Matrix* const m, int type) {
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 =
@ -245,7 +245,7 @@ static void SetupMatrices(VP8Encoder* enc) {
for (i = 0; i < num_segments; ++i) {
VP8SegmentInfo* const m = &enc->dqm_[i];
const int q = m->quant_;
int q4, q16, quv;
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)];
@ -255,21 +255,33 @@ static void SetupMatrices(VP8Encoder* enc) {
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)];
q4 = ExpandMatrix(&m->y1_, 0);
q16 = ExpandMatrix(&m->y2_, 1);
quv = ExpandMatrix(&m->uv_, 2);
q_i4 = ExpandMatrix(&m->y1_, 0);
q_i16 = ExpandMatrix(&m->y2_, 1);
q_uv = ExpandMatrix(&m->uv_, 2);
m->lambda_i4_ = (3 * q4 * q4) >> 7;
m->lambda_i16_ = (3 * q16 * q16);
m->lambda_uv_ = (3 * quv * quv) >> 6;
m->lambda_mode_ = (1 * q4 * q4) >> 7;
m->lambda_trellis_i4_ = (7 * q4 * q4) >> 3;
m->lambda_trellis_i16_ = (q16 * q16) >> 2;
m->lambda_trellis_uv_ = (quv *quv) << 1;
m->tlambda_ = (tlambda_scale * q4) >> 5;
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_ = 10 * m->y1_.q_[0]; // quantization-aware min disto
m->max_edge_ = 0;
m->i4_penalty_ = 1000 * q_i4 * q_i4;
}
}
@ -1127,19 +1139,29 @@ static void RefineUsingDistortion(VP8EncIterator* const it,
int try_both_modes, int refine_uv_mode,
VP8ModeScore* const rd) {
score_t best_score = MAX_COST;
score_t score_i4 = (score_t)I4_PENALTY;
int16_t tmp_levels[16][16];
uint8_t modes_i4[16];
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 = it->enc_->mb_header_limit_;
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);
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;
@ -1159,25 +1181,28 @@ static void RefineUsingDistortion(VP8EncIterator* const it,
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);
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;
}
}
modes_i4[it->i4_] = best_i4_mode;
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) {
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, tmp_levels[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));
@ -1185,8 +1210,7 @@ static void RefineUsingDistortion(VP8EncIterator* const it,
// Final reconstruction, depending on which mode is selected.
if (!is_i16) {
VP8SetIntra4Mode(it, modes_i4);
memcpy(rd->y_ac_levels, tmp_levels, sizeof(tmp_levels));
VP8SetIntra4Mode(it, rd->modes_i4);
SwapOut(it);
best_score = score_i4;
} else {
@ -1200,7 +1224,8 @@ static void RefineUsingDistortion(VP8EncIterator* const it,
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);
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;

4
src/enc/vp8enci.h
View File

@ -196,6 +196,9 @@ typedef struct {
int lambda_i16_, lambda_i4_, lambda_uv_;
int lambda_mode_, lambda_trellis_, tlambda_;
int lambda_trellis_i16_, lambda_trellis_i4_, lambda_trellis_uv_;
// lambda values for distortion-based evaluation
score_t i4_penalty_; // penalty for using Intra4
} VP8SegmentInfo;
// Handy transient struct to accumulate score and info during RD-optimization
@ -391,6 +394,7 @@ struct VP8Encoder {
int method_; // 0=fastest, 6=best/slowest.
VP8RDLevel rd_opt_level_; // Deduced from method_.
int max_i4_header_bits_; // partition #0 safeness factor
int mb_header_limit_; // rough limit for header bits per MB
int thread_level_; // derived from config->thread_level
int do_search_; // derived from config->target_XXX
int use_tokens_; // if true, use token buffer

4
src/enc/webpenc.c
View File

@ -105,6 +105,10 @@ static void MapConfigToTools(VP8Encoder* const enc) {
256 * 16 * 16 * // upper bound: up to 16bit per 4x4 block
(limit * limit) / (100 * 100); // ... modulated with a quadratic curve.
// partition0 = 512k max.
enc->mb_header_limit_ =
(score_t)256 * 510 * 8 * 1024 / (enc->mb_w_ * enc->mb_h_);
enc->thread_level_ = config->thread_level;
enc->do_search_ = (config->target_size > 0 || config->target_PSNR > 0);