Only write mode-ref-delta if meaningful
Instead of writing 0 values when all mode-ref-deltas are zero,
signal at a higher level that no deltas will be present.
STATS_CHANGED
Improves PSNR BDrate by ~0.01% (midres) to ~0.02% (lowres). No speed change.
Change-Id: Ib1b8fc011873504ba6982af9a37f4df00f0114e9
diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index f3f5a76..8834b6f 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -1939,12 +1939,41 @@
}
}
+// Only write out the ref delta section if any of the elements
+// will signal a delta.
+static bool is_mode_ref_delta_meaningful(AV1_COMMON *cm) {
+ struct loopfilter *lf = &cm->lf;
+ if (!lf->mode_ref_delta_update) {
+ return 0;
+ }
+ const RefCntBuffer *buf = get_primary_ref_frame_buf(cm);
+ int8_t last_ref_deltas[REF_FRAMES];
+ int8_t last_mode_deltas[MAX_MODE_LF_DELTAS];
+ if (buf == NULL) {
+ av1_set_default_ref_deltas(last_ref_deltas);
+ av1_set_default_mode_deltas(last_mode_deltas);
+ } else {
+ memcpy(last_ref_deltas, buf->ref_deltas, REF_FRAMES);
+ memcpy(last_mode_deltas, buf->mode_deltas, MAX_MODE_LF_DELTAS);
+ }
+ for (int i = 0; i < REF_FRAMES; i++) {
+ if (lf->ref_deltas[i] != last_ref_deltas[i]) {
+ return true;
+ }
+ }
+ for (int i = 0; i < MAX_MODE_LF_DELTAS; i++) {
+ if (lf->mode_deltas[i] != last_mode_deltas[i]) {
+ return true;
+ }
+ }
+ return false;
+}
+
static AOM_INLINE void encode_loopfilter(AV1_COMMON *cm,
struct aom_write_bit_buffer *wb) {
assert(!cm->coded_lossless);
if (cm->allow_intrabc) return;
const int num_planes = av1_num_planes(cm);
- int i;
struct loopfilter *lf = &cm->lf;
// Encode the loop filter level and type
@@ -1958,41 +1987,37 @@
}
aom_wb_write_literal(wb, lf->sharpness_level, 3);
- // Write out loop filter deltas applied at the MB level based on mode or
- // ref frame (if they are enabled).
aom_wb_write_bit(wb, lf->mode_ref_delta_enabled);
- if (lf->mode_ref_delta_enabled) {
- aom_wb_write_bit(wb, lf->mode_ref_delta_update);
+ // Write out loop filter deltas applied at the MB level based on mode or
+ // ref frame (if they are enabled), only if there is information to write.
+ int meaningful = is_mode_ref_delta_meaningful(cm);
+ aom_wb_write_bit(wb, meaningful);
+ if (!meaningful) {
+ return;
+ }
- if (lf->mode_ref_delta_update) {
- const RefCntBuffer *buf = get_primary_ref_frame_buf(cm);
- int8_t last_ref_deltas[REF_FRAMES];
- if (buf == NULL) {
- av1_set_default_ref_deltas(last_ref_deltas);
- } else {
- memcpy(last_ref_deltas, buf->ref_deltas, REF_FRAMES);
- }
- for (i = 0; i < REF_FRAMES; i++) {
- const int delta = lf->ref_deltas[i];
- const int changed = delta != last_ref_deltas[i];
- aom_wb_write_bit(wb, changed);
- if (changed) aom_wb_write_inv_signed_literal(wb, delta, 6);
- }
-
- int8_t last_mode_deltas[MAX_MODE_LF_DELTAS];
- if (buf == NULL) {
- av1_set_default_mode_deltas(last_mode_deltas);
- } else {
- memcpy(last_mode_deltas, buf->mode_deltas, MAX_MODE_LF_DELTAS);
- }
- for (i = 0; i < MAX_MODE_LF_DELTAS; i++) {
- const int delta = lf->mode_deltas[i];
- const int changed = delta != last_mode_deltas[i];
- aom_wb_write_bit(wb, changed);
- if (changed) aom_wb_write_inv_signed_literal(wb, delta, 6);
- }
- }
+ const RefCntBuffer *buf = get_primary_ref_frame_buf(cm);
+ int8_t last_ref_deltas[REF_FRAMES];
+ int8_t last_mode_deltas[MAX_MODE_LF_DELTAS];
+ if (buf == NULL) {
+ av1_set_default_ref_deltas(last_ref_deltas);
+ av1_set_default_mode_deltas(last_mode_deltas);
+ } else {
+ memcpy(last_ref_deltas, buf->ref_deltas, REF_FRAMES);
+ memcpy(last_mode_deltas, buf->mode_deltas, MAX_MODE_LF_DELTAS);
+ }
+ for (int i = 0; i < REF_FRAMES; i++) {
+ const int delta = lf->ref_deltas[i];
+ const int changed = delta != last_ref_deltas[i];
+ aom_wb_write_bit(wb, changed);
+ if (changed) aom_wb_write_inv_signed_literal(wb, delta, 6);
+ }
+ for (int i = 0; i < MAX_MODE_LF_DELTAS; i++) {
+ const int delta = lf->mode_deltas[i];
+ const int changed = delta != last_mode_deltas[i];
+ aom_wb_write_bit(wb, changed);
+ if (changed) aom_wb_write_inv_signed_literal(wb, delta, 6);
}
}
