libvpx: Pull from upstream

source/libvpx/vp9/encoder/vp9_svc_layercontext.c

 /*
  *  Copyright (c) 2014 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 261 matching lines @@
   w += w % 2;
   h += h % 2;
 
   *width_out = w;
   *height_out = h;
 }
 
 int vp9_svc_start_frame(VP9_COMP *const cpi) {
   int width = 0, height = 0;
   LAYER_CONTEXT *lc;
+  struct lookahead_entry *buf;
   int count = 1 << (cpi->svc.number_temporal_layers - 1);
 
   cpi->svc.spatial_layer_id = cpi->svc.spatial_layer_to_encode;
   lc = &cpi->svc.layer_context[cpi->svc.spatial_layer_id];
 
   cpi->svc.temporal_layer_id = 0;
   while ((lc->current_video_frame_in_layer % count) != 0) {
     ++cpi->svc.temporal_layer_id;
     count >>= 1;
   }
@@ skipping 40 matching lines @@
   }
 
   get_layer_resolution(cpi->oxcf.width, cpi->oxcf.height,
                        lc->scaling_factor_num, lc->scaling_factor_den,
                        &width, &height);
 
   // Workaround for multiple frame contexts. In some frames we can't use prev_mi
   // since its previous frame could be changed during decoding time. The idea is
   // we put a empty invisible frame in front of them, then we will not use
   // prev_mi when encoding these frames.
+
+  buf = vp9_lookahead_peek(cpi->lookahead, 0);
   if (cpi->oxcf.error_resilient_mode == 0 && cpi->oxcf.pass == 2 &&
-      cpi->svc.encode_empty_frame_state == NEED_TO_ENCODE) {
+      cpi->svc.encode_empty_frame_state == NEED_TO_ENCODE &&
+      lc->rc.frames_to_key != 0 &&
+      !(buf != NULL && (buf->flags & VPX_EFLAG_FORCE_KF))) {
     if ((cpi->svc.number_temporal_layers > 1 &&
          cpi->svc.temporal_layer_id < cpi->svc.number_temporal_layers - 1) ||
         (cpi->svc.number_spatial_layers > 1 &&
          cpi->svc.spatial_layer_id == 0)) {
       struct lookahead_entry *buf = vp9_lookahead_peek(cpi->lookahead, 0);
 
       if (buf != NULL) {
         cpi->svc.empty_frame.ts_start = buf->ts_start;
         cpi->svc.empty_frame.ts_end = buf->ts_end;
         cpi->svc.encode_empty_frame_state = ENCODING;
@@ skipping 46 matching lines @@
       // Only remove the buffer when pop the highest layer.
       if (cpi->svc.spatial_layer_id == cpi->svc.number_spatial_layers - 1) {
         vp9_lookahead_pop(ctx, drain);
       }
     }
   }
 
   return buf;
 }
 #endif