Add the q_segmentation experiment
This experiment implements low-cost delta q signalling on a per-block basis
for all non-inter frame types, which would allow for more efficient AQ
which bases its decisions on temporal information.
Based on an Intel proposal from March.
Change-Id: I18e73d8b12f4caa0b165df12c58ab506271bec03
diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index f964d3b..1340cef 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -744,6 +744,79 @@
}
#endif // CONFIG_LV_MAP
+#if CONFIG_Q_SEGMENTATION
+static int neg_interleave(int x, int ref, int max) {
+ const int diff = x - ref;
+ if (!ref) return x;
+ if (ref >= (max - 1)) return -diff;
+ if (2 * ref < max) {
+ if (abs(diff) <= ref) {
+ if (diff > 0)
+ return (diff << 1) - 1;
+ else
+ return ((-diff) << 1);
+ }
+ return x;
+ } else {
+ if (abs(diff) < (max - ref)) {
+ if (diff > 0)
+ return (diff << 1) - 1;
+ else
+ return ((-diff) << 1);
+ }
+ return (max - x) - 1;
+ }
+}
+
+static void write_q_segment_id(const AV1_COMMON *cm, int skip,
+ const MB_MODE_INFO *const mbmi, aom_writer *w,
+ const struct segmentation *seg,
+ struct segmentation_probs *segp,
+ BLOCK_SIZE bsize, int mi_row, int mi_col) {
+ int prev_ul = 0; /* Top left segment_id */
+ int prev_l = 0; /* Current left segment_id */
+ int prev_u = 0; /* Current top segment_id */
+
+ if (!seg->q_lvls) return;
+
+ MODE_INFO *const mi = cm->mi + mi_row * cm->mi_stride + mi_col;
+ int tinfo = mi->mbmi.boundary_info;
+ int above = (!(tinfo & TILE_ABOVE_BOUNDARY)) && ((mi_row - 1) >= 0);
+ int left = (!(tinfo & TILE_LEFT_BOUNDARY)) && ((mi_col - 1) >= 0);
+
+ if (above && left)
+ prev_ul =
+ get_segment_id(cm, cm->q_seg_map, BLOCK_4X4, mi_row - 1, mi_col - 1);
+
+ if (above)
+ prev_u = get_segment_id(cm, cm->q_seg_map, BLOCK_4X4, mi_row - 1, mi_col);
+
+ if (left)
+ prev_l = get_segment_id(cm, cm->q_seg_map, BLOCK_4X4, mi_row, mi_col - 1);
+
+ int cdf_num = pick_q_seg_cdf(prev_ul, prev_u, prev_l);
+ int pred = pick_q_seg_pred(prev_ul, prev_u, prev_l);
+
+ if (skip) {
+ set_q_segment_id(cm, cm->q_seg_map, mbmi->sb_type, mi_row, mi_col, pred);
+ return;
+ }
+
+ int coded_id = neg_interleave(mbmi->q_segment_id, pred, seg->q_lvls);
+
+#if CONFIG_NEW_MULTISYMBOL
+ aom_cdf_prob *pred_cdf = segp->q_seg_cdf[cdf_num];
+ aom_write_symbol(w, coded_id, pred_cdf, 8);
+#else
+ aom_prob pred_cdf = segp->q_seg_cdf[cdf_num];
+ aom_write(w, coded_id, pred_prob);
+#endif
+
+ set_q_segment_id(cm, cm->q_seg_map, bsize, mi_row, mi_col,
+ mbmi->q_segment_id);
+}
+#endif
+
static void write_segment_id(aom_writer *w, const struct segmentation *seg,
struct segmentation_probs *segp, int segment_id) {
if (seg->enabled && seg->update_map) {
@@ -1319,6 +1392,9 @@
}
skip = write_skip(cm, xd, segment_id, mi, w);
+#if CONFIG_Q_SEGMENTATION
+ write_q_segment_id(cm, skip, mbmi, w, seg, segp, bsize, mi_row, mi_col);
+#endif
if (cm->delta_q_present_flag) {
int super_block_upper_left = ((mi_row & (cm->mib_size - 1)) == 0) &&
((mi_col & (cm->mib_size - 1)) == 0);
@@ -1644,6 +1720,9 @@
if (seg->update_map) write_segment_id(w, seg, segp, mbmi->segment_id);
const int skip = write_skip(cm, xd, mbmi->segment_id, mi, w);
+#if CONFIG_Q_SEGMENTATION
+ write_q_segment_id(cm, skip, mbmi, w, seg, segp, bsize, mi_row, mi_col);
+#endif
if (cm->delta_q_present_flag) {
int super_block_upper_left = ((mi_row & (cm->mib_size - 1)) == 0) &&
((mi_col & (cm->mib_size - 1)) == 0);
@@ -2747,6 +2826,32 @@
}
}
+#if CONFIG_Q_SEGMENTATION
+static void encode_q_segmentation(AV1_COMMON *cm,
+ struct aom_write_bit_buffer *wb) {
+ int i;
+ struct segmentation *seg = &cm->seg;
+
+ for (i = 0; i < MAX_SEGMENTS; i++) {
+ if (segfeature_active(seg, i, SEG_LVL_ALT_Q)) {
+ seg->q_lvls = 0;
+ return;
+ }
+ }
+
+ aom_wb_write_bit(wb, !!seg->q_lvls);
+ if (!seg->q_lvls) return;
+
+ encode_unsigned_max(wb, seg->q_lvls, MAX_SEGMENTS);
+
+ for (i = 0; i < seg->q_lvls; i++) {
+ const int val = seg->q_delta[i];
+ encode_unsigned_max(wb, abs(val), MAXQ);
+ aom_wb_write_bit(wb, val < 0);
+ }
+}
+#endif
+
static void write_tx_mode(AV1_COMMON *cm, TX_MODE *mode,
struct aom_write_bit_buffer *wb) {
if (cm->all_lossless) {
@@ -3916,6 +4021,9 @@
encode_loopfilter(cm, wb);
encode_quantization(cm, wb);
encode_segmentation(cm, xd, wb);
+#if CONFIG_Q_SEGMENTATION
+ encode_q_segmentation(cm, wb);
+#endif
{
int delta_q_allowed = 1;
#if !CONFIG_EXT_DELTA_Q
@@ -4270,6 +4378,9 @@
encode_loopfilter(cm, wb);
encode_quantization(cm, wb);
encode_segmentation(cm, xd, wb);
+#if CONFIG_Q_SEGMENTATION
+ encode_q_segmentation(cm, wb);
+#endif
{
int delta_q_allowed = 1;
#if !CONFIG_EXT_DELTA_Q
