vp9-svc: Add new frame drop mode for SVC

add SVC framedrop mode: Lower spatial layers
are constrained to drop if current spatial layer
needs to drop.

No change in behavior to other existing modes.

Change-Id: I2d37959caf8c4b453b405904831b550367f716ba

1 files changed, 7 insertions, 14 deletions

diff --git a/vp9/encoder/vp9_encoder.c b/vp9/encoder/vp9_encoder.c
index 25464b3b8..c18e3d5aa 100644
--- a/vp9/encoder/vp9_encoder.c
+++ b/vp9/encoder/vp9_encoder.c
@@ -4982,12 +4982,15 @@ static void encode_frame_to_data_rate(VP9_COMP *cpi, size_t *size,
   TX_SIZE t;
 
   // SVC: skip encoding of enhancement layer if the layer target bandwidth = 0.
-  // If in constrained layer drop mode (svc.framedrop_mode != LAYER_DROP) and
-  // base spatial layer was dropped, no need to set svc.skip_enhancement_layer,
-  // as whole superframe will be dropped.
+  // No need to set svc.skip_enhancement_layer if whole superframe will be
+  // dropped.
   if (cpi->use_svc && cpi->svc.spatial_layer_id > 0 &&
       cpi->oxcf.target_bandwidth == 0 &&
       !(cpi->svc.framedrop_mode != LAYER_DROP &&
+        (cpi->svc.framedrop_mode != CONSTRAINED_FROM_ABOVE_DROP ||
+         cpi->svc
+             .force_drop_constrained_from_above[cpi->svc.number_spatial_layers -
+                                                1]) &&
         cpi->svc.drop_spatial_layer[0])) {
     cpi->svc.skip_enhancement_layer = 1;
     vp9_rc_postencode_update_drop_frame(cpi);
@@ -4995,17 +4998,7 @@ static void encode_frame_to_data_rate(VP9_COMP *cpi, size_t *size,
     cpi->last_frame_dropped = 1;
     cpi->svc.last_layer_dropped[cpi->svc.spatial_layer_id] = 1;
     cpi->svc.drop_spatial_layer[cpi->svc.spatial_layer_id] = 1;
-    if (cpi->svc.framedrop_mode == LAYER_DROP ||
-        cpi->svc.drop_spatial_layer[0] == 0) {
-      // For the case of constrained drop mode 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);
-    }
+    vp9_inc_frame_in_layer(cpi);
     return;
   }