1 // Copyright (c) 2012 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_AUDIO_CRAS_CRAS_INPUT_H_ 6 #define MEDIA_AUDIO_CRAS_CRAS_INPUT_H_ 7 8 #include <cras_client.h> 9 10 #include <string> 11 12 #include "base/compiler_specific.h" 13 #include "media/audio/agc_audio_stream.h" 14 #include "media/audio/audio_io.h" 15 #include "media/audio/audio_parameters.h" 16 17 namespace media { 18 19 class AudioManagerCras; 20 21 // Provides an input stream for audio capture based on CRAS, the ChromeOS Audio 22 // Server. This object is not thread safe and all methods should be invoked in 23 // the thread that created the object. 24 class CrasInputStream : public AgcAudioStream<AudioInputStream> { 25 public: 26 // The ctor takes all the usual parameters, plus |manager| which is the 27 // audio manager who is creating this object. 28 CrasInputStream(const AudioParameters& params, AudioManagerCras* manager, 29 const std::string& device_id); 30 31 // The dtor is typically called by the AudioManager only and it is usually 32 // triggered by calling AudioOutputStream::Close(). 33 virtual ~CrasInputStream(); 34 35 // Implementation of AudioInputStream. 36 virtual bool Open() OVERRIDE; 37 virtual void Start(AudioInputCallback* callback) OVERRIDE; 38 virtual void Stop() OVERRIDE; 39 virtual void Close() OVERRIDE; 40 virtual double GetMaxVolume() OVERRIDE; 41 virtual void SetVolume(double volume) OVERRIDE; 42 virtual double GetVolume() OVERRIDE; 43 virtual bool IsMuted() OVERRIDE; 44 45 private: 46 // Handles requests to get samples from the provided buffer. This will be 47 // called by the audio server when it has samples ready. 48 static int SamplesReady(cras_client* client, 49 cras_stream_id_t stream_id, 50 uint8* samples, 51 size_t frames, 52 const timespec* sample_ts, 53 void* arg); 54 55 // Handles notification that there was an error with the playback stream. 56 static int StreamError(cras_client* client, 57 cras_stream_id_t stream_id, 58 int err, 59 void* arg); 60 61 // Reads one or more buffers of audio from the device, passes on to the 62 // registered callback. Called from SamplesReady(). 63 void ReadAudio(size_t frames, uint8* buffer, const timespec* sample_ts); 64 65 // Deals with an error that occured in the stream. Called from StreamError(). 66 void NotifyStreamError(int err); 67 68 // Convert from dB * 100 to a volume ratio. 69 double GetVolumeRatioFromDecibels(double dB) const; 70 71 // Convert from a volume ratio to dB. 72 double GetDecibelsFromVolumeRatio(double volume_ratio) const; 73 74 // Non-refcounted pointer back to the audio manager. 75 // The AudioManager indirectly holds on to stream objects, so we don't 76 // want circular references. Additionally, stream objects live on the audio 77 // thread, which is owned by the audio manager and we don't want to addref 78 // the manager from that thread. 79 AudioManagerCras* const audio_manager_; 80 81 // Size of frame in bytes. 82 uint32 bytes_per_frame_; 83 84 // Callback to pass audio samples too, valid while recording. 85 AudioInputCallback* callback_; 86 87 // The client used to communicate with the audio server. 88 cras_client* client_; 89 90 // PCM parameters for the stream. 91 const AudioParameters params_; 92 93 // True if the stream has been started. 94 bool started_; 95 96 // ID of the playing stream. 97 cras_stream_id_t stream_id_; 98 99 // Direction of the stream. 100 const CRAS_STREAM_DIRECTION stream_direction_; 101 102 scoped_ptr<AudioBus> audio_bus_; 103 104 DISALLOW_COPY_AND_ASSIGN(CrasInputStream); 105 }; 106 107 } // namespace media 108 109 #endif // MEDIA_AUDIO_CRAS_CRAS_INPUT_H_ 110