VP8:Setting number of cores based on image size
Review URL: http://webrtc-codereview.appspot.com/242010

git-svn-id: http://webrtc.googlecode.com/svn/trunk@806 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/src/modules/video_coding/codecs/vp8/main/source/vp8.cc b/src/modules/video_coding/codecs/vp8/main/source/vp8.cc
index 7babda8..8214bb1 100644
--- a/src/modules/video_coding/codecs/vp8/main/source/vp8.cc
+++ b/src/modules/video_coding/codecs/vp8/main/source/vp8.cc
@@ -299,7 +299,13 @@
 #endif
     _cfg->g_lag_in_frames = 0; // 0- no frame lagging
 
-    _cfg->g_threads = numberOfCores;
+    // Determining number of threads based on the image size
+
+    if (_width * _height > 704 * 576 && numberOfCores > 1)
+      // 2 threads when larger than 4CIF
+      _cfg->g_threads = 2;
+    else
+      _cfg->g_threads = 1;
 
     // rate control settings
     _cfg->rc_dropframe_thresh = 0;
@@ -782,7 +788,8 @@
 #endif
 
     vpx_codec_dec_cfg_t  cfg;
-    cfg.threads = numberOfCores;
+    // Setting number of threads to a constant value (1)
+    cfg.threads = 1;
     cfg.h = cfg.w = 0; // set after decode
 
     vpx_codec_flags_t flags = 0;