NetEq: Use a BuiltinAudioDecoderFactory to create decoders

webrtc/modules/audio_coding/acm2/rent_a_codec.cc

Index: webrtc/modules/audio_coding/acm2/rent_a_codec.cc
diff --git a/webrtc/modules/audio_coding/acm2/rent_a_codec.cc b/webrtc/modules/audio_coding/acm2/rent_a_codec.cc
index 7f1e52030dc944f9efe244d8fd7f96eec432ebc8..13079ad0493825a5e72ac71ce5384602305b5864 100644
--- a/webrtc/modules/audio_coding/acm2/rent_a_codec.cc
+++ b/webrtc/modules/audio_coding/acm2/rent_a_codec.cc
@@ -47,6 +47,55 @@
 namespace webrtc {
 namespace acm2 {
 
+rtc::Optional<SdpAudioFormat> RentACodec::NetEqDecoderToSdpAudioFormat(
+    NetEqDecoder nd) {
+  switch (nd) {
+    case NetEqDecoder::kDecoderPCMu:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("pcmu", 8000, 1));
+    case NetEqDecoder::kDecoderPCMa:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("pcma", 8000, 1));
+    case NetEqDecoder::kDecoderPCMu_2ch:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("pcmu", 8000, 2));
+    case NetEqDecoder::kDecoderPCMa_2ch:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("pcma", 8000, 2));
+    case NetEqDecoder::kDecoderILBC:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("ilbc", 8000, 1));
+    case NetEqDecoder::kDecoderISAC:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("isac", 16000, 1));
+    case NetEqDecoder::kDecoderISACswb:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("isac", 32000, 1));
+    case NetEqDecoder::kDecoderPCM16B:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("l16", 8000, 1));
+    case NetEqDecoder::kDecoderPCM16Bwb:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("l16", 16000, 1));
+    case NetEqDecoder::kDecoderPCM16Bswb32kHz:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("l16", 32000, 1));
+    case NetEqDecoder::kDecoderPCM16Bswb48kHz:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("l16", 48000, 1));
+    case NetEqDecoder::kDecoderPCM16B_2ch:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("l16", 8000, 2));
+    case NetEqDecoder::kDecoderPCM16Bwb_2ch:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("l16", 16000, 2));
+    case NetEqDecoder::kDecoderPCM16Bswb32kHz_2ch:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("l16", 32000, 2));
+    case NetEqDecoder::kDecoderPCM16Bswb48kHz_2ch:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("l16", 48000, 2));
+    case NetEqDecoder::kDecoderPCM16B_5ch:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("l16", 8000, 5));
+    case NetEqDecoder::kDecoderG722:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("g722", 8000, 1));
+    case NetEqDecoder::kDecoderG722_2ch:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("g722", 8000, 2));
+    case NetEqDecoder::kDecoderOpus:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("opus", 48000, 1));
+    case NetEqDecoder::kDecoderOpus_2ch:
+      return rtc::Optional<SdpAudioFormat>(SdpAudioFormat("opus", 48000, 2));

[ossu, 2016/04/29 12:21:33]

Opus is weird and always wants to have a channel count of 2, with an optional
parameter setting stereo=1 or stereo=0 to actually decide the number of
channels.

[kwiberg-webrtc, 2016/04/29 23:10:13]

I was hoping to be able to postpone the introduction of this sort of
complication, and just use the obvious mapping for now. Is that a bad idea, do
you think? (Hmm. I already have g722's whacky sample rate in here, so if this
Opus oddity is the only other one, perhaps I should just put it in there and be
done with it?)

[ossu, 2016/05/02 10:59:40]

Might as well do it "the right (wrong) way" from the start. :)

[kwiberg-webrtc, 2016/05/02 20:20:00]

Done.

+
+    default:
+      return rtc::Optional<SdpAudioFormat>();
+  }
+}
+
 rtc::Optional<RentACodec::CodecId> RentACodec::CodecIdByParams(
     const char* payload_name,
     int sampling_freq_hz,