1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef MEDIA_CAST_RECEIVER_AUDIO_DECODER_H_ 6 #define MEDIA_CAST_RECEIVER_AUDIO_DECODER_H_ 7 8 #include "base/callback.h" 9 #include "base/memory/ref_counted.h" 10 #include "media/base/audio_bus.h" 11 #include "media/cast/cast_config.h" 12 #include "media/cast/cast_environment.h" 13 #include "media/cast/transport/cast_transport_config.h" 14 15 namespace media { 16 namespace cast { 17 18 class AudioDecoder { 19 public: 20 // Callback passed to DecodeFrame, to deliver decoded audio data from the 21 // decoder. The number of samples in |audio_bus| may vary, and |audio_bus| 22 // can be NULL when errors occur. |is_continuous| is normally true, but will 23 // be false if the decoder has detected a frame skip since the last decode 24 // operation; and the client should take steps to smooth audio discontinuities 25 // in this case. 26 typedef base::Callback<void(scoped_ptr<AudioBus> audio_bus, 27 bool is_continuous)> DecodeFrameCallback; 28 29 AudioDecoder(const scoped_refptr<CastEnvironment>& cast_environment, 30 int channels, 31 int sampling_rate, 32 transport::AudioCodec codec); 33 virtual ~AudioDecoder(); 34 35 // Returns STATUS_AUDIO_INITIALIZED if the decoder was successfully 36 // constructed from the given FrameReceiverConfig. If this method returns any 37 // other value, calls to DecodeFrame() will not succeed. 38 CastInitializationStatus InitializationResult() const; 39 40 // Decode the payload in |encoded_frame| asynchronously. |callback| will be 41 // invoked on the CastEnvironment::MAIN thread with the result. 42 // 43 // In the normal case, |encoded_frame->frame_id| will be 44 // monotonically-increasing by 1 for each successive call to this method. 45 // When it is not, the decoder will assume one or more frames have been 46 // dropped (e.g., due to packet loss), and will perform recovery actions. 47 void DecodeFrame(scoped_ptr<transport::EncodedFrame> encoded_frame, 48 const DecodeFrameCallback& callback); 49 50 private: 51 class ImplBase; 52 class OpusImpl; 53 class Pcm16Impl; 54 55 const scoped_refptr<CastEnvironment> cast_environment_; 56 scoped_refptr<ImplBase> impl_; 57 58 DISALLOW_COPY_AND_ASSIGN(AudioDecoder); 59 }; 60 61 } // namespace cast 62 } // namespace media 63 64 #endif // MEDIA_CAST_RECEIVER_AUDIO_DECODER_H_ 65