Do not terminate palette mode search using rd estimation
Function "model_intra_yrd_and_prune()" was redesigned in CL:
https://aomedia-review.googlesource.com/c/aom/+/130501,
which skips an intra mode search when its estimated rd cost is
1.25 times larger than the current best rd cost.
It causes function "av1_determine_sc_tools_with_encoding()"
fail to identify screen content videos. A quality regression is
seen on screen content videos.
The reason is that palette mode is significantly different to
traditional intra modes. The pruning might not work well for it.
Removing this early termination in palette mode allows the function
"av1_determine_sc_tools_with_encoding()" to effectively detect
whether to use screen content tools.
For example, clip "chinaspeed_xga" now uses screen content tools
after this change.
As compared to the current head, on speed 4, screen content set,
the coding performance is improved by
-1.67% (ovr_psnr), -1.49% (ssim).
STATS_CHANGED
Change-Id: Iad8d15029c3db3c0c5e72ec0bd46be7df0fab932
diff --git a/av1/encoder/palette.c b/av1/encoder/palette.c
index d1380c7..26f2248 100644
--- a/av1/encoder/palette.c
+++ b/av1/encoder/palette.c
@@ -222,6 +222,7 @@
int *rate, int *rate_tokenonly, int64_t *distortion, int *skippable,
int *beat_best_rd, PICK_MODE_CONTEXT *ctx, uint8_t *blk_skip,
uint8_t *tx_type_map, int *beat_best_palette_rd) {
+ (void)best_model_rd;
optimize_palette_colors(color_cache, n_cache, n, 1, centroids,
cpi->common.seq_params->bit_depth);
const int num_unique_colors = av1_remove_duplicates(centroids, n);
@@ -251,10 +252,6 @@
1);
extend_palette_color_map(color_map, cols, rows, block_width, block_height);
- if (model_intra_yrd_and_prune(cpi, x, bsize, best_model_rd)) {
- return;
- }
-
RD_STATS tokenonly_rd_stats;
av1_pick_uniform_tx_size_type_yrd(cpi, x, &tokenonly_rd_stats, bsize,
*best_rd);
