1 // Copyright 2013 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 // Creates a unified stream based on the cras (ChromeOS audio server) interface.
7 // CrasUnifiedStream object is *not* thread-safe and should only be used
8 // from the audio thread.
10 #ifndef MEDIA_AUDIO_LINUX_CRAS_UNIFIED_H_
11 #define MEDIA_AUDIO_LINUX_CRAS_UNIFIED_H_
13 #include <alsa/asoundlib.h>
14 #include <cras_client.h>
16 #include "base/compiler_specific.h"
17 #include "base/gtest_prod_util.h"
18 #include "media/audio/audio_io.h"
19 #include "media/audio/audio_parameters.h"
23 class AudioManagerCras;
24 class AudioParameters;
26 // Implementation of AudioOuputStream for Chrome OS using the Chrome OS audio
28 class MEDIA_EXPORT CrasUnifiedStream : public AudioOutputStream {
30 // The ctor takes all the usual parameters, plus |manager| which is the
31 // audio manager who is creating this object.
32 CrasUnifiedStream(const AudioParameters& params, AudioManagerCras* manager);
34 // The dtor is typically called by the AudioManager only and it is usually
35 // triggered by calling AudioUnifiedStream::Close().
36 virtual ~CrasUnifiedStream();
38 // Implementation of AudioOutputStream.
39 virtual bool Open() OVERRIDE;
40 virtual void Close() OVERRIDE;
41 virtual void Start(AudioSourceCallback* callback) OVERRIDE;
42 virtual void Stop() OVERRIDE;
43 virtual void SetVolume(double volume) OVERRIDE;
44 virtual void GetVolume(double* volume) OVERRIDE;
47 // Convert Latency in time to bytes.
48 uint32 GetBytesLatency(const struct timespec& latency);
50 // Handles captured audio and fills the ouput with audio to be played.
51 static int UnifiedCallback(cras_client* client,
52 cras_stream_id_t stream_id,
54 uint8* output_samples,
56 const timespec* input_ts,
57 const timespec* output_ts,
60 // Handles notificaiton that there was an error with the playback stream.
61 static int StreamError(cras_client* client,
62 cras_stream_id_t stream_id,
66 // Chooses the correct audio callback based on stream direction.
67 uint32 DispatchCallback(size_t frames,
69 uint8* output_samples,
70 const timespec* input_ts,
71 const timespec* output_ts);
73 // Receives input samples and write output samples for a unified I/O stream.
74 uint32 ReadWriteAudio(size_t frames,
76 uint8* output_samples,
77 const timespec* input_ts,
78 const timespec* output_ts);
80 // Writes audio for a playback stream.
81 uint32 WriteAudio(size_t frames, uint8* buffer, const timespec* sample_ts);
83 // Deals with an error that occured in the stream. Called from StreamError().
84 void NotifyStreamError(int err);
86 // The client used to communicate with the audio server.
89 // ID of the playing stream.
90 cras_stream_id_t stream_id_;
92 // PCM parameters for the stream.
93 AudioParameters params_;
95 // Size of frame in bytes.
96 uint32 bytes_per_frame_;
98 // True if stream is playing.
101 // Volume level from 0.0 to 1.0.
104 // Audio manager that created us. Used to report that we've been closed.
105 AudioManagerCras* manager_;
107 // Callback to get audio samples.
108 AudioSourceCallback* source_callback_;
110 // Container for exchanging data with AudioSourceCallback::OnMoreIOData().
111 scoped_ptr<AudioBus> input_bus_;
112 scoped_ptr<AudioBus> output_bus_;
114 // Direciton of the stream.
115 CRAS_STREAM_DIRECTION stream_direction_;
117 DISALLOW_COPY_AND_ASSIGN(CrasUnifiedStream);
122 #endif // MEDIA_AUDIO_LINUX_CRAS_UNIFIED_H_