Opus: Let the decoder interpret 2-byte payloads as DTX/CNG packets

webrtc/modules/audio_coding/codecs/opus/opus_interface.c

Index: webrtc/modules/audio_coding/codecs/opus/opus_interface.c
diff --git a/webrtc/modules/audio_coding/codecs/opus/opus_interface.c b/webrtc/modules/audio_coding/codecs/opus/opus_interface.c
index 41e17ae51058e7c9e8e4a67ecd4f3beaa4a133d3..5bb3472b5a899fe3d0d2aa7b3ebbc2578b5242b8 100644
--- a/webrtc/modules/audio_coding/codecs/opus/opus_interface.c
+++ b/webrtc/modules/audio_coding/codecs/opus/opus_interface.c
@@ -283,7 +283,11 @@ static int16_t DetermineAudioType(OpusDecInst* inst, size_t encoded_bytes) {
   // to be so if the following |encoded_byte| are 0 or 1.
   if (encoded_bytes == 0 && inst->in_dtx_mode) {
     return 2;  // Comfort noise.
-  } else if (encoded_bytes == 1) {
+  } else if (encoded_bytes == 1 || encoded_bytes == 2) {
+    // TODO(henrik.lundin): There is a slight risk that a 2-byte payload is in
+    // fact a 1-byte TOC with a 1-byte payload. That will be erroneously
+    // interpreted as comfort noise output, but such a payload is probably
+    // faulty anyway.
     inst->in_dtx_mode = 1;
     return 2;  // Comfort noise.
   } else {