vp9-svc: Put check on usage of long term temporal ref.

If the scale factor of the golden long term reference
is different from the last reference then disable usage
of long term reference.

This should not happen, but add this as a check against
some possibly incorrect update of the svc configuration.

Change-Id: Ic1062d4384e005007d8c922813fa8ad188d8fa98

diff --git a/vp9/encoder/vp9_pickmode.c b/vp9/encoder/vp9_pickmode.c
index 8dce4cf7b46dcefffbaba7d6b59f32abd2d5e6b9..1324b5bc8aa4f4667e29dedcee5843082e0d3670 100644 (file)
--- a/vp9/encoder/vp9_pickmode.c
+++ b/vp9/encoder/vp9_pickmode.c
@@ -1732,11 +1732,21 @@ void vp9_pick_inter_mode(VP9_COMP *cpi, MACROBLOCK *x, TileDataEnc *tile_data,
   if (!cpi->use_svc ||
       (svc->use_gf_temporal_ref_current_layer &&
        !svc->layer_context[svc->temporal_layer_id].is_key_frame)) {
+    struct scale_factors *const sf_last = &cm->frame_refs[LAST_FRAME - 1].sf;
+    struct scale_factors *const sf_golden =
+        &cm->frame_refs[GOLDEN_FRAME - 1].sf;
     gf_temporal_ref = 1;
-    if (cpi->rc.avg_frame_low_motion > 70)
-      thresh_svc_skip_golden = 500;
-    else
-      thresh_svc_skip_golden = 0;
+    // For temporal long term prediction, check that the golden reference
+    // is same scale as last reference, otherwise disable.
+    if ((sf_last->x_scale_fp != sf_golden->x_scale_fp) ||
+        (sf_last->y_scale_fp != sf_golden->y_scale_fp)) {
+      gf_temporal_ref = 0;
+    } else {
+      if (cpi->rc.avg_frame_low_motion > 70)
+        thresh_svc_skip_golden = 500;
+      else
+        thresh_svc_skip_golden = 0;
+    }
   }
 
   init_ref_frame_cost(cm, xd, ref_frame_cost);