vp9: Use 2 threads for 360p.

webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc

 /*
  *  Copyright (c) 2014 The WebRTC 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 363 matching lines @@
   return InitAndSetControlSettings(inst);
 }
 
 int VP9EncoderImpl::NumberOfThreads(int width,
                                     int height,
                                     int number_of_cores) {
   // Keep the number of encoder threads equal to the possible number of column
   // tiles, which is (1, 2, 4, 8). See comments below for VP9E_SET_TILE_COLUMNS.
   if (width * height >= 1280 * 720 && number_of_cores > 4) {
     return 4;
-  } else if (width * height >= 640 * 480 && number_of_cores > 2) {
+  } else if (width * height >= 640 * 360 && number_of_cores > 2) {
     return 2;
   } else {
     // 1 thread less than VGA.
     return 1;
   }
 }
 
 int VP9EncoderImpl::InitAndSetControlSettings(const VideoCodec* inst) {
   // Set QP-min/max per spatial and temporal layer.
   int tot_num_layers = num_spatial_layers_ * num_temporal_layers_;
@@ skipping 613 matching lines @@
   frame_buffer_pool_.ClearPool();
   inited_ = false;
   return WEBRTC_VIDEO_CODEC_OK;
 }
 
 const char* VP9DecoderImpl::ImplementationName() const {
   return "libvpx";
 }
 
 }  // namespace webrtc