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.
5 #ifndef MEDIA_AUDIO_CRAS_CRAS_INPUT_H_
6 #define MEDIA_AUDIO_CRAS_CRAS_INPUT_H_
8 #include <cras_client.h>
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"
19 class AudioManagerCras;
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> {
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);
31 // The dtor is typically called by the AudioManager only and it is usually
32 // triggered by calling AudioOutputStream::Close().
33 virtual ~CrasInputStream();
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;
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,
52 const timespec* sample_ts,
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,
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);
65 // Deals with an error that occured in the stream. Called from StreamError().
66 void NotifyStreamError(int err);
68 // Convert from dB * 100 to a volume ratio.
69 double GetVolumeRatioFromDecibels(double dB) const;
71 // Convert from a volume ratio to dB.
72 double GetDecibelsFromVolumeRatio(double volume_ratio) const;
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_;
81 // Size of frame in bytes.
82 uint32 bytes_per_frame_;
84 // Callback to pass audio samples too, valid while recording.
85 AudioInputCallback* callback_;
87 // The client used to communicate with the audio server.
90 // PCM parameters for the stream.
91 const AudioParameters params_;
93 // True if the stream has been started.
96 // ID of the playing stream.
97 cras_stream_id_t stream_id_;
99 // Direction of the stream.
100 const CRAS_STREAM_DIRECTION stream_direction_;
102 scoped_ptr<AudioBus> audio_bus_;
104 DISALLOW_COPY_AND_ASSIGN(CrasInputStream);
109 #endif // MEDIA_AUDIO_CRAS_CRAS_INPUT_H_