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