Changing default bitrate to 64000 bps for Opus.

Default settings for Opus in WebRtc is stereo, but we had default rate to 32 kbps. This is too low for stereo, where we need to encode using 64 kbps to get the quality we like.

BUG=

Review URL: https://webrtc-codereview.appspot.com/974008

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@3223 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/modules/audio_coding/main/source/acm_codec_database.cc b/modules/audio_coding/main/source/acm_codec_database.cc
index 19bccb6..1c9a409 100644
--- a/modules/audio_coding/main/source/acm_codec_database.cc
+++ b/modules/audio_coding/main/source/acm_codec_database.cc
@@ -191,7 +191,7 @@
 #ifdef WEBRTC_CODEC_OPUS
   // Opus internally supports 48, 24, 16, 12, 8 kHz.
   // Mono and stereo.
-  {120, "opus", 48000, 960, 2, 32000},
+  {120, "opus", 48000, 960, 2, 64000},
 #endif
 #ifdef WEBRTC_CODEC_SPEEX
   {kDynamicPayloadtypes[count_database++], "speex", 8000, 160, 1, 11000},