Moved codec-specific audio packet splitting into decoders.

webrtc/modules/audio_coding/codecs/g722/audio_decoder_g722.cc

Index: webrtc/modules/audio_coding/codecs/g722/audio_decoder_g722.cc
diff --git a/webrtc/modules/audio_coding/codecs/g722/audio_decoder_g722.cc b/webrtc/modules/audio_coding/codecs/g722/audio_decoder_g722.cc
index 379293b748b043985488e180934c2dd5c9baf060..9956d793d682065504a9928009b62243de592c67 100644
--- a/webrtc/modules/audio_coding/codecs/g722/audio_decoder_g722.cc
+++ b/webrtc/modules/audio_coding/codecs/g722/audio_decoder_g722.cc
@@ -47,6 +47,12 @@ void AudioDecoderG722::Reset() {
   WebRtcG722_DecoderInit(dec_state_);
 }
 
+AudioDecoder::PacketSplits AudioDecoderG722::SplitPacket(
+    const uint8_t* payload,
+    size_t payload_len) const {
+  return SplitBySamples(payload, payload_len, 8, 16);

[kwiberg-webrtc, 2016/08/26 12:39:24]

You could probably make the SplitBySamples calls easier to read by making named
locals for the third and fourth arguments.

+}
+
 int AudioDecoderG722::PacketDuration(const uint8_t* encoded,
                                      size_t encoded_len) const {
   // 1/2 encoded byte per sample per channel.
@@ -117,6 +123,17 @@ void AudioDecoderG722Stereo::Reset() {
   WebRtcG722_DecoderInit(dec_state_right_);
 }
 
+AudioDecoder::PacketSplits AudioDecoderG722Stereo::SplitPacket(
+    const uint8_t* payload,
+    size_t payload_len) const {
+  // TODO(ossu): There didn't seem to be splitting in place for this before, but
+  //             from looking at the code, it seems this should work: the two
+  //             channels are interleaved (since they need to be explicitly
+  //             deinterleaved before decoding) so regular splitting should be
+  //             fine.

[kwiberg-webrtc, 2016/08/26 12:39:24]

I agree. (And I don't think this comment needs to be in the code.)

[ossu, 2016/08/26 13:05:30]

Cool. I've put this TODO here so that it doesn't get glossed over in review.
I'll remove it before landing.

+  return SplitBySamples(payload, payload_len, 2 * 8, 16);
+}
+
 // Split the stereo packet and place left and right channel after each other
 // in the output array.
 void AudioDecoderG722Stereo::SplitStereoPacket(const uint8_t* encoded,