shithub: libvpx

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Short circuit flat blocks when coding screen content at realtime speed.

In inter mode search skip all modes except NEARESTMV and DC_PRED.

10% less encode latency for large frames using the chromium remoting_perftests.

+0.313% BDRATE on the screencast set at speed -6.

Change-Id: Ib97a39dd8bcdeab545509e0e02d78ce7033f8c63

--- a/vp9/encoder/vp9_pickmode.c

+++ b/vp9/encoder/vp9_pickmode.c

@@ -1251,6 +1251,17 @@

   mi->tx_size = VPXMIN(max_txsize_lookup[bsize],

                        tx_mode_to_biggest_tx_size[cm->tx_mode]);

+  if (sf->short_circuit_flat_blocks) {

+#if CONFIG_VP9_HIGHBITDEPTH

+    if (xd->cur_buf->flags & YV12_FLAG_HIGHBITDEPTH)

+      x->source_variance = vp9_high_get_sby_perpixel_variance(

+          cpi, &x->plane[0].src, bsize, xd->bd);

+    else

+#endif  // CONFIG_VP9_HIGHBITDEPTH

+      x->source_variance =

+          vp9_get_sby_perpixel_variance(cpi, &x->plane[0].src, bsize);

+  }

+

 #if CONFIG_VP9_TEMPORAL_DENOISING

   vp9_denoiser_reset_frame_stats(ctx);

 #endif

@@ -1289,6 +1300,11 @@

     if (cpi->use_svc)

       this_mode = ref_mode_set_svc[idx].pred_mode;

+    if (sf->short_circuit_flat_blocks && x->source_variance == 0 &&

+        this_mode != NEARESTMV) {

+      continue;

+    }

+

     if (!(cpi->sf.inter_mode_mask[bsize] & (1 << this_mode)))

       continue;

@@ -1704,6 +1720,10 @@

       const PREDICTION_MODE this_mode = intra_mode_list[i];

       THR_MODES mode_index = mode_idx[INTRA_FRAME][mode_offset(this_mode)];

       int mode_rd_thresh = rd_threshes[mode_index];

+      if (sf->short_circuit_flat_blocks && x->source_variance == 0 &&

+          this_mode != DC_PRED) {

+        continue;

+      }

       if (!((1 << this_mode) & cpi->sf.intra_y_mode_bsize_mask[bsize]))

         continue;

--- a/vp9/encoder/vp9_rd.h

+++ b/vp9/encoder/vp9_rd.h

@@ -182,6 +182,15 @@

 int vp9_get_intra_cost_penalty(int qindex, int qdelta,

                                vpx_bit_depth_t bit_depth);

+unsigned int vp9_get_sby_perpixel_variance(struct VP9_COMP *cpi,

+                                           const struct buf_2d *ref,

+                                           BLOCK_SIZE bs);

+#if CONFIG_VP9_HIGHBITDEPTH

+unsigned int vp9_high_get_sby_perpixel_variance(struct VP9_COMP *cpi,

+                                                const struct buf_2d *ref,

+                                                BLOCK_SIZE bs, int bd);

+#endif

+

 #ifdef __cplusplus

 }  // extern "C"

 #endif

--- a/vp9/encoder/vp9_rdopt.h

+++ b/vp9/encoder/vp9_rdopt.h

@@ -29,15 +29,6 @@

                                struct RD_COST *rd_cost, BLOCK_SIZE bsize,

                                PICK_MODE_CONTEXT *ctx, int64_t best_rd);

-unsigned int vp9_get_sby_perpixel_variance(VP9_COMP *cpi,

-                                           const struct buf_2d *ref,

-                                           BLOCK_SIZE bs);

-#if CONFIG_VP9_HIGHBITDEPTH

-unsigned int vp9_high_get_sby_perpixel_variance(VP9_COMP *cpi,

-                                                const struct buf_2d *ref,

-                                                BLOCK_SIZE bs, int bd);

-#endif

-

 void vp9_rd_pick_inter_mode_sb(struct VP9_COMP *cpi,

                                struct TileDataEnc *tile_data,

                                struct macroblock *x,

--- a/vp9/encoder/vp9_speed_features.c

+++ b/vp9/encoder/vp9_speed_features.c

@@ -401,6 +401,9 @@

             sf->intra_y_mode_bsize_mask[i] = INTRA_DC_H_V;

       }

     }

+    if (content == VP9E_CONTENT_SCREEN) {

+      sf->short_circuit_flat_blocks = 1;

+    }

   }

   if (speed >= 6) {

@@ -534,6 +537,7 @@

   sf->recode_tolerance = 25;

   sf->default_interp_filter = SWITCHABLE;

   sf->simple_model_rd_from_var = 0;

+  sf->short_circuit_flat_blocks = 0;

   // Some speed-up features even for best quality as minimal impact on quality.

   sf->adaptive_rd_thresh = 1;

--- a/vp9/encoder/vp9_speed_features.h

+++ b/vp9/encoder/vp9_speed_features.h

@@ -438,6 +438,10 @@

   // Fast approximation of vp9_model_rd_from_var_lapndz

   int simple_model_rd_from_var;

+

+  // Skip a number of expensive mode evaluations for blocks with zero source

+  // variance.

+  int short_circuit_flat_blocks;

 } SPEED_FEATURES;

 struct VP9_COMP;