vp9-svc: Enable use of second temporal reference for SVC.

When inter-layer is disabled on INTER frames, this will allow
use of a second (longer term) temporal reference for SVC.

Only enabled on highest resolution spatial layer.

Average gains of ~4% on RTC set, speed decrease of about ~2%.

Change-Id: I3c2d415653c448eb7269c828e120fe8bb2ef3f97

diff --git a/vp9/encoder/vp9_svc_layercontext.c b/vp9/encoder/vp9_svc_layercontext.c
index f5baa7cddbf394dd7a98a12b9afd6f574fea769f..a72083b61fec59b818864f9467a1e102440c365f 100644 (file)
--- a/vp9/encoder/vp9_svc_layercontext.c
+++ b/vp9/encoder/vp9_svc_layercontext.c
@@ -33,7 +33,7 @@ void vp9_init_layer_context(VP9_COMP *const cpi) {
   svc->force_zero_mode_spatial_ref = 0;
   svc->use_base_mv = 0;
   svc->use_partition_reuse = 0;
-  svc->use_longterm_ref = 0;
+  svc->use_longterm_ref = 1;
   svc->use_longterm_ref_current_layer = 0;
   svc->scaled_temp_is_alloc = 0;
   svc->scaled_one_half = 0;