Opus implementation of the AudioDecoderFactoryTemplate API

webrtc/api/audio_codecs/opus/audio_decoder_opus.h

Index: webrtc/api/audio_codecs/opus/audio_decoder_opus.h
diff --git a/webrtc/api/audio_codecs/opus/audio_decoder_opus.h b/webrtc/api/audio_codecs/opus/audio_decoder_opus.h
new file mode 100644
index 0000000000000000000000000000000000000000..c2868bd9353f9f862f4ac7c43ad053347620f800
--- /dev/null
+++ b/webrtc/api/audio_codecs/opus/audio_decoder_opus.h
@@ -0,0 +1,38 @@
+/*
+ *  Copyright (c) 2017 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_API_AUDIO_CODECS_OPUS_AUDIO_DECODER_OPUS_H_
+#define WEBRTC_API_AUDIO_CODECS_OPUS_AUDIO_DECODER_OPUS_H_
+
+#include <memory>
+#include <vector>
+
+#include "webrtc/api/audio_codecs/audio_decoder.h"
+#include "webrtc/api/audio_codecs/audio_format.h"
+#include "webrtc/base/optional.h"
+
+namespace webrtc {
+
+// Opus decoder API for use as a template parameter to
+// CreateAudioDecoderFactory<...>().
+//
+// NOTE: This struct is still under development and may change without notice.
+struct AudioDecoderOpus {
+  struct Config {
+    int num_channels;
+  };
+  static rtc::Optional<Config> SdpToConfig(const SdpAudioFormat& audio_format);
+  static void AppendSupportedDecoders(std::vector<AudioCodecSpec>* specs);
+  static std::unique_ptr<AudioDecoder> MakeAudioDecoder(Config config);

[the sun, 2017/06/16 12:49:14]

const &?

[kwiberg-webrtc, 2017/06/18 00:42:38]

That struct contains only an int, so pass-by-value seems appropriate.

+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_API_AUDIO_CODECS_OPUS_AUDIO_DECODER_OPUS_H_