vp9-svc: Fix when whole superframe is dropped.

When the whole superframe is dropped (due to rate control),
don't increment the temporal layer counter.

This is a temporary fix to prevent an issue where temporal
prediction pattern is possibly broken.

Updated svc_datarate tests to handle this case.

Change-Id: Icac44fdc9d0f08a957776c937584db4b2c7927c7

1 files changed, 11 insertions, 1 deletions

diff --git a/vp9/encoder/vp9_encoder.c b/vp9/encoder/vp9_encoder.c
index 3384de7ea..13f01a3ab 100644
--- a/vp9/encoder/vp9_encoder.c
+++ b/vp9/encoder/vp9_encoder.c
@@ -4560,8 +4560,18 @@ static void encode_frame_to_data_rate(VP9_COMP *cpi, size_t *size,
       if (cpi->use_svc) {
         cpi->svc.last_layer_dropped[cpi->svc.spatial_layer_id] = 1;
         cpi->svc.drop_spatial_layer[cpi->svc.spatial_layer_id] = 1;
-        vp9_inc_frame_in_layer(cpi);
         cpi->svc.skip_enhancement_layer = 1;
+        if (cpi->svc.framedrop_mode != CONSTRAINED_LAYER_DROP ||
+            cpi->svc.drop_spatial_layer[0] == 0) {
+          // For the case of CONSTRAINED_LAYER_DROP where the base is dropped
+          // (drop_spatial_layer[0] == 1), which means full superframe dropped,
+          // we don't increment the svc frame counters. In particular temporal
+          // layer counter (which is incremented in vp9_inc_frame_in_layer())
+          // won't be incremented, so on a dropped frame we try the same
+          // temporal_layer_id on next incoming frame. This is to avoid an
+          // issue with temporal alignement with full superframe dropping.
+          vp9_inc_frame_in_layer(cpi);
+        }
         if (cpi->svc.spatial_layer_id == cpi->svc.number_spatial_layers - 1) {
           int i;
           int all_layers_drop = 1;