shithub: libvpx

Download patch

ref: e447a1a33426f249f67875bbbf31aac08b82d52a
parent: e5b858740aed35a6f2eb7bf84adb993ccd1962f2
author: Marco Paniconi <marpan@google.com>
date: Fri May 18 11:09:55 EDT 2018

vp9-svc: Fix on disabling inter_layer prediction.

In vp9_svc_constrain_inter_layer_pred() we disable the
inter_layer prediction if anything but only the previous
spatial layer (from same supeframe) is used for inter_layer
prediction. This check and disabling was only allowed when
the control VP9E_SET_SVC_INTER_LAYER_PRED is set to
INTER_LAYER_PRED_ON_CONSTRAINED.

But the control VP9E_SET_SVC_INTER_LAYER_PRED is needed for setting:
INTER_LAYER_PRED_ON/INTER_LAYER_PRED_OFF/INTER_LAYER_PRED_OFF_NONKEY.
So there is a conflict with setting INTER_LAYER_PRED_ON_CONSTRAINED.

Fix for now is to always allow for this disabling check
(disable inter_layer reference if its not previous spatial layer) as
long as inter_layer prediction is used (i.e., not set to _OFF).

A separate fix if needed may be to invoke another control for setting
INTER_LAYER_PRED_ON_CONSTRAINED.

This was causing an issue with enabling spatial layers on the fly
(say spatial layer 2), where since INTER_LAYER_PRED_ON_CONSTRAINED was
not set (default), the inter_layer prediction was then using a reference
from 2 spatial layers below (spatial layer 0).

Change-Id: Ic6434000665f63aab27c509b5eb7b8fc965827bc

--- a/vp9/encoder/vp9_svc_layercontext.c

+++ b/vp9/encoder/vp9_svc_layercontext.c

@@ -906,12 +906,11 @@

       }

     }

   }

-  // Check for disabling inter-layer prediction if

-  // INTER_LAYER_PRED_ON_CONSTRAINED is enabled.

-  // If the reference for inter-layer prediction (the reference that is scaled)

-  // is not the previous spatial layer from the same superframe, then we

-  // disable inter-layer prediction.

-  if (cpi->svc.disable_inter_layer_pred == INTER_LAYER_PRED_ON_CONSTRAINED) {

+  // Check for disabling inter-layer prediction if the reference for inter-layer

+  // prediction (the reference that is scaled) is not the previous spatial layer

+  // from the same superframe, then we disable inter-layer prediction.

+  // Only need to check when inter_layer prediction is not set to OFF mode.

+  if (cpi->svc.disable_inter_layer_pred != INTER_LAYER_PRED_OFF) {

     // We only use LAST and GOLDEN for prediction in real-time mode, so we

     // check both here.

     MV_REFERENCE_FRAME ref_frame;