vp9-svc: Add QP dependency to thresh_svc_skip_golden.

In nonrd-pickmode: the golden/spatial reference for inter-layer
prediction may be skipped in the mode testing. Add QP dependency
to reduce the threshold for skipping (i.e., check it more often)
at high QP, if the lower layer was encoded at lower QP relative
to the current layer.

At high QP, a better quality lower resolution is more likely to
provide good spatial (inter-layer) prediction.

avgPSNR/SSIM metrics up by ~1% (all clips positive gain or neutral).
Some decrease in encode time (~1-2%) expected at lower bitrates,
for 3 layer SVC.

Change-Id: I9ee0f62d4b10d4ebd30165d378ecfa4399ae5ef1

diff --git a/vp9/encoder/vp9_pickmode.c b/vp9/encoder/vp9_pickmode.c
index ef03384e48bb0a6f6cb7794fcdddc58aca3fd48e..185653d803c210471a441bed4552b856411a136b 100644 (file)
--- a/vp9/encoder/vp9_pickmode.c
+++ b/vp9/encoder/vp9_pickmode.c
@@ -1488,7 +1488,6 @@ void vp9_pick_inter_mode(VP9_COMP *cpi, MACROBLOCK *x, TileDataEnc *tile_data,
   int skip_ref_find_pred[4] = { 0 };
   unsigned int sse_zeromv_normalized = UINT_MAX;
   unsigned int best_sse_sofar = UINT_MAX;
-  unsigned int thresh_svc_skip_golden = 500;
 #if CONFIG_VP9_TEMPORAL_DENOISING
   VP9_PICKMODE_CTX_DEN ctx_den;
   int64_t zero_last_cost_orig = INT64_MAX;
@@ -1501,6 +1500,17 @@ void vp9_pick_inter_mode(VP9_COMP *cpi, MACROBLOCK *x, TileDataEnc *tile_data,
   int flag_svc_subpel = 0;
   int svc_mv_col = 0;
   int svc_mv_row = 0;
+  unsigned int thresh_svc_skip_golden = 500;
+  // Lower the skip threshold if lower spatial layer is better quality relative
+  // to current layer.
+  if (cpi->svc.spatial_layer_id > 0 && cm->base_qindex > 150 &&
+      cm->base_qindex > cpi->svc.lower_layer_qindex + 15)
+    thresh_svc_skip_golden = 100;
+  // Increase skip threshold if lower spatial layer is lower quality relative
+  // to current layer.
+  else if (cpi->svc.spatial_layer_id > 0 && cm->base_qindex < 140 &&
+           cm->base_qindex < cpi->svc.lower_layer_qindex - 20)
+    thresh_svc_skip_golden = 1000;
 
   init_ref_frame_cost(cm, xd, ref_frame_cost);
 

diff --git a/vp9/encoder/vp9_ratectrl.c b/vp9/encoder/vp9_ratectrl.c
index 3e40cce8e5b9f9b61a332a7966cd3cef68de63a0..72647bf8edf04ad1f16252add09ee989f704a73f 100644 (file)
--- a/vp9/encoder/vp9_ratectrl.c
+++ b/vp9/encoder/vp9_ratectrl.c
@@ -1490,6 +1490,9 @@ void vp9_rc_postencode_update(VP9_COMP *cpi, uint64_t bytes_used) {
   if (cm->frame_type != KEY_FRAME) rc->reset_high_source_sad = 0;
 
   rc->last_avg_frame_bandwidth = rc->avg_frame_bandwidth;
+  if (cpi->use_svc &&
+      cpi->svc.spatial_layer_id < cpi->svc.number_spatial_layers - 1)
+    cpi->svc.lower_layer_qindex = cm->base_qindex;
 }
 
 void vp9_rc_postencode_update_drop_frame(VP9_COMP *cpi) {

diff --git a/vp9/encoder/vp9_svc_layercontext.h b/vp9/encoder/vp9_svc_layercontext.h
index 8b708e271a02ca65a1ffc90d20aaeda01aca3359..87686fe59f9d39756845a3eeabb84bcd57a19243 100644 (file)
--- a/vp9/encoder/vp9_svc_layercontext.h
+++ b/vp9/encoder/vp9_svc_layercontext.h
@@ -103,6 +103,8 @@ typedef struct SVC {
   int first_layer_denoise;
 
   int skip_enhancement_layer;
+
+  int lower_layer_qindex;
 } SVC;
 
 struct VP9_COMP;