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Add missing lambda to some bit costs

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Bits were being added to rate distortion without being multiplied by
lambda in a few places. Fixing this bug also finally allows us to remove
the magic bits from the Coding Unit split decision.

I tried to find new optimum value for CU_COST and it turned out to be 2
for veryslow and 0 for superfast. The difference between 0 and 2 on
veryslow was only 0.1% however, so I don't think this parameter is
needed any longer. Before this fix the effect of removing CU_COST would
have been 0.8%.
This commit is contained in:
Ari Koivula 2015-12-15 16:25:19 +02:00
parent 0e33049d9e
commit a6ea705e19
1 changed files with 10 additions and 14 deletions
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24
src/search.c
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@ -47,12 +47,6 @@
# define INTRA_TRESHOLD 20
#endif
// Extra cost for CU split.
// Compensates for missing or incorrect bit costs. Must be recalculated if
// bits are added or removed from cu-tree search.
#ifndef CU_COST
# define CU_COST 3
#endif
// Disable early cu-split pruning.
#ifndef FULL_CU_SPLIT_SEARCH
# define FULL_CU_SPLIT_SEARCH false
@ -681,22 +675,22 @@ static double search_cu(encoder_state_t * const state, int x, int y, int depth,
// Recursively split all the way to max search depth.
if (depth < ctrl->pu_depth_intra.max || (depth < ctrl->pu_depth_inter.max && state->global->slicetype != KVZ_SLICE_I)) {
int half_cu = cu_width / 2;
// Using Cost = lambda * 9 to compensate on the price of the split
double split_cost = state->global->cur_lambda_cost * CU_COST;
double split_cost = 0.0;
int cbf = cbf_is_set(cur_cu->cbf.y, depth) || cbf_is_set(cur_cu->cbf.u, depth) || cbf_is_set(cur_cu->cbf.v, depth);
if (depth < MAX_DEPTH) {
// Add cost of cu_split_flag.
uint8_t split_model = get_ctx_cu_split_model(lcu, x, y, depth);
const cabac_ctx_t *ctx = &(state->cabac.ctx.split_flag_model[split_model]);
cost += CTX_ENTROPY_FBITS(ctx, 0);
split_cost += CTX_ENTROPY_FBITS(ctx, 1);
cost += CTX_ENTROPY_FBITS(ctx, 0) * state->global->cur_lambda_cost;
split_cost += CTX_ENTROPY_FBITS(ctx, 1) * state->global->cur_lambda_cost;
}
if (cur_cu->type == CU_INTRA && depth == MAX_DEPTH) {
// Add cost of intra part_size.
const cabac_ctx_t *ctx = &(state->cabac.ctx.part_size_model[0]);
cost += CTX_ENTROPY_FBITS(ctx, 1); // 2Nx2N
split_cost += CTX_ENTROPY_FBITS(ctx, 0); // NxN
cost += CTX_ENTROPY_FBITS(ctx, 1) * state->global->cur_lambda_cost; // 2Nx2N
split_cost += CTX_ENTROPY_FBITS(ctx, 0) * state->global->cur_lambda_cost; // NxN
}
// If skip mode was selected for the block, skip further search.
@ -738,10 +732,12 @@ static double search_cu(encoder_state_t * const state, int x, int y, int depth,
cost += kvz_cu_rd_cost_luma(state, x_local, y_local, depth, cur_cu, &work_tree[depth]);
cost += kvz_cu_rd_cost_chroma(state, x_local, y_local, depth, cur_cu, &work_tree[depth]);
// Add the cost of coding no-split.
uint8_t split_model = get_ctx_cu_split_model(lcu, x, y, depth);
const cabac_ctx_t *ctx = &(state->cabac.ctx.split_flag_model[split_model]);
cost += CTX_ENTROPY_FBITS(ctx, 0);
cost += CTX_ENTROPY_FBITS(ctx, 0) * state->global->cur_lambda_cost;
// Add the cost of coding intra mode only once.
double mode_bits = calc_mode_bits(state, cur_cu, x, y);
cost += mode_bits * state->global->cur_lambda_cost;
}