shithub: libvpx

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vp9-svc: Modify early breakout for non-rd pickmode

Modify early breakout condition for non-rd pickmode
for quality layers: when lower layer has lower QP force
test of zeromv on golden (lower layer reference) before
breakout due to skip.

Reduce artifacts, observed in cases of scrolling content.

Change-Id: Id834b1eb024a4c97f0e74d8b7f7a0351459e088f

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

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

@@ -1683,6 +1683,7 @@

   unsigned int sse_zeromv_normalized = UINT_MAX;

   unsigned int best_sse_sofar = UINT_MAX;

   int gf_temporal_ref = 0;

+  int force_test_gf_zeromv = 0;

 #if CONFIG_VP9_TEMPORAL_DENOISING

   VP9_PICKMODE_CTX_DEN ctx_den;

   int64_t zero_last_cost_orig = INT64_MAX;

@@ -1939,6 +1940,13 @@

     flag_svc_subpel = 1;

   }

+  // For SVC with quality layers, when QP of lower layer is lower

+  // than current layer: force check of GF-ZEROMV before early exit

+  // due to skip flag.

+  if (svc->spatial_layer_id > 0 && usable_ref_frame == GOLDEN_FRAME &&

+      no_scaling && cm->base_qindex > svc->lower_layer_qindex + 10)

+    force_test_gf_zeromv = 1;

+

   for (idx = 0; idx < num_inter_modes + comp_modes; ++idx) {

     int rate_mv = 0;

     int mode_rd_thresh;

@@ -2349,11 +2357,14 @@

       if (reuse_inter_pred) free_pred_buffer(this_mode_pred);

     }

-    if (x->skip) break;

+    if (x->skip &&

+        (!force_test_gf_zeromv || mode_checked[ZEROMV][GOLDEN_FRAME]))

+      break;

     // If early termination flag is 1 and at least 2 modes are checked,

     // the mode search is terminated.

-    if (best_early_term && idx > 0 && !scene_change_detected) {

+    if (best_early_term && idx > 0 && !scene_change_detected &&

+        (!force_test_gf_zeromv || mode_checked[ZEROMV][GOLDEN_FRAME])) {

       x->skip = 1;

       break;

     }