Prevent Opus DTX from generating intermittent noise during silence

webrtc/modules/audio_coding/codecs/opus/opus_inst.h

 /*
  *  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.
  */
 
 #ifndef WEBRTC_MODULES_AUDIO_CODING_CODECS_OPUS_OPUS_INST_H_
 #define WEBRTC_MODULES_AUDIO_CODING_CODECS_OPUS_OPUS_INST_H_
 
 #include "opus.h"
 
 struct WebRtcOpusEncInst {
   OpusEncoder* encoder;
+  int channels;
   int in_dtx_mode;
+  // Count consecutive zeros during DTX. We break long zero segment to prevent
+  // DTX from going wrong.
+  size_t* zero_counts;

[kwiberg-webrtc, 2015/10/29 16:35:21]

What is this number more exactly? The number of consecutive zero samples ending
with the last sample received? (Also, mention that there's one counter per
channel.)

[minyue-webrtc, 2015/10/30 14:06:46]

I made some change in wording. I hope it is clearer.

 };
 
 struct WebRtcOpusDecInst {
   OpusDecoder* decoder;
   int prev_decoded_samples;
   int channels;
   int in_dtx_mode;
 };
 
 
 #endif  // WEBRTC_MODULES_AUDIO_CODING_CODECS_OPUS_OPUS_INST_H_