Merge "Disallow skipping transform and quantization" into main

Cheng Chen committed 5 years ago

Commit 7c5574a2 parents bd53f0c fe1c7d24 files · +20 −13Browse files

Unified · Split

4 files

vp9/encoder/vp9_block.h +3 −0
vp9/encoder/vp9_rdopt.c +10 −13
vp9/encoder/vp9_speed_features.c +1 −0
vp9/encoder/vp9_speed_features.h +6 −0

   // skip forward transform and quantization
   uint8_t skip_txfm[MAX_MB_PLANE << 2];
 #define SKIP_TXFM_NONE 0
+// TODO(chengchen): consider remove SKIP_TXFM_AC_DC from vp9 completely
+// since it increases risks of bad perceptual quality.
+// https://crbug.com/webm/1729
 #define SKIP_TXFM_AC_DC 1
 #define SKIP_TXFM_AC_ONLY 2

vp9/encoder/vp9_rdopt.c+10−13

   MODE_INFO *const mi = xd->mi[0];
   int64_t rd1, rd2, rd;
   int rate;
-  int64_t dist;
+  int64_t dist = INT64_MAX;
-  int64_t sse;
+  int64_t sse = INT64_MAX;
   const int coeff_ctx =
       combine_entropy_contexts(args->t_left[blk_row], args->t_above[blk_col]);
   struct buf_2d *recon = args->this_recon;
     if (max_txsize_lookup[plane_bsize] == tx_size)
       skip_txfm_flag = x->skip_txfm[(plane << 2) + (block >> (tx_size << 1))];
+    // This reduces the risk of bad perceptual quality due to bad prediction.
+    // We always force the encoder to perform transform and quantization.
+    if (!args->cpi->sf.allow_skip_txfm_ac_dc &&
+        skip_txfm_flag == SKIP_TXFM_AC_DC) {
+      skip_txfm_flag = SKIP_TXFM_NONE;
+    }
     if (skip_txfm_flag == SKIP_TXFM_NONE ||
         (recon && skip_txfm_flag == SKIP_TXFM_AC_ONLY)) {
       // full forward transform and quantization
         dist = VPXMAX(0, sse - dc_correct);
       }
     } else {
-      // SKIP_TXFM_AC_DC
+      assert(0 && "allow_skip_txfm_ac_dc does not allow SKIP_TXFM_AC_DC.");
-      // skip forward transform. Because this is handled here, the quantization
-      // does not need to do it.
-      x->plane[plane].eobs[block] = 0;
-      sse = x->bsse[(plane << 2) + (block >> (tx_size << 1))] << 4;
-      dist = sse;
-      if (recon) {
-        uint8_t *rec_ptr = &recon->buf[4 * (blk_row * recon->stride + blk_col)];
-        copy_block_visible(xd, pd, dst, dst_stride, rec_ptr, recon->stride,
-                           blk_row, blk_col, plane_bsize, tx_bsize);
-      }
     }
   }

vp9/encoder/vp9_speed_features.c+1−0

@@ -940,6 +940,7 @@ void vp9_set_speed_features_framesize_independent(VP9_COMP *cpi, int speed) { · 939 unmodified lines
940	sf->enable_tpl_model = oxcf->enable_tpl_model;	940	sf->enable_tpl_model = oxcf->enable_tpl_model;
941	sf->prune_ref_frame_for_rect_partitions = 0;	941	sf->prune_ref_frame_for_rect_partitions = 0;
942	sf->temporal_filter_search_method = MESH;	942	sf->temporal_filter_search_method = MESH;
		943	sf->allow_skip_txfm_ac_dc = 0;
943		944
944	for (i = 0; i < TX_SIZES; i++) {	945	for (i = 0; i < TX_SIZES; i++) {
945	sf->intra_y_mode_mask[i] = INTRA_ALL;	946	sf->intra_y_mode_mask[i] = INTRA_ALL;

vp9/encoder/vp9_speed_features.h+6−0

   // For real-time mode: force DC only under intra search when content
   // does not have high souce SAD.
   int rt_intra_dc_only_low_content;
+  // The encoder has a feature that skips forward transform and quantization
+  // based on a model rd estimation to reduce encoding time.
+  // However, this feature is dangerous since it could lead to bad perceptual
+  // quality. This flag is added to guard the feature.
+  int allow_skip_txfm_ac_dc;
 } SPEED_FEATURES;
 struct VP9_COMP;

Merge "Disallow skipping transform and quantization" into main

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