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 17namespace media { 18 19class 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. 24class 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 44 private: 45 // Handles requests to get samples from the provided buffer. This will be 46 // called by the audio server when it has samples ready. 47 static int SamplesReady(cras_client* client, 48 cras_stream_id_t stream_id, 49 uint8* samples, 50 size_t frames, 51 const timespec* sample_ts, 52 void* arg); 53 54 // Handles notification that there was an error with the playback stream. 55 static int StreamError(cras_client* client, 56 cras_stream_id_t stream_id, 57 int err, 58 void* arg); 59 60 // Reads one or more buffers of audio from the device, passes on to the 61 // registered callback. Called from SamplesReady(). 62 void ReadAudio(size_t frames, uint8* buffer, const timespec* sample_ts); 63 64 // Deals with an error that occured in the stream. Called from StreamError(). 65 void NotifyStreamError(int err); 66 67 // Convert from dB * 100 to a volume ratio. 68 double GetVolumeRatioFromDecibels(double dB) const; 69 70 // Convert from a volume ratio to dB. 71 double GetDecibelsFromVolumeRatio(double volume_ratio) const; 72 73 // Non-refcounted pointer back to the audio manager. 74 // The AudioManager indirectly holds on to stream objects, so we don't 75 // want circular references. Additionally, stream objects live on the audio 76 // thread, which is owned by the audio manager and we don't want to addref 77 // the manager from that thread. 78 AudioManagerCras* const audio_manager_; 79 80 // Size of frame in bytes. 81 uint32 bytes_per_frame_; 82 83 // Callback to pass audio samples too, valid while recording. 84 AudioInputCallback* callback_; 85 86 // The client used to communicate with the audio server. 87 cras_client* client_; 88 89 // PCM parameters for the stream. 90 const AudioParameters params_; 91 92 // True if the stream has been started. 93 bool started_; 94 95 // ID of the playing stream. 96 cras_stream_id_t stream_id_; 97 98 // Direction of the stream. 99 const CRAS_STREAM_DIRECTION stream_direction_; 100 101 scoped_ptr<AudioBus> audio_bus_; 102 103 DISALLOW_COPY_AND_ASSIGN(CrasInputStream); 104}; 105 106} // namespace media 107 108#endif // MEDIA_AUDIO_CRAS_CRAS_INPUT_H_ 109