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.
4//
5// Creates a unified stream based on the cras (ChromeOS audio server) interface.
6//
7// CrasUnifiedStream object is *not* thread-safe and should only be used
8// from the audio thread.
9
10#ifndef MEDIA_AUDIO_LINUX_CRAS_UNIFIED_H_
11#define MEDIA_AUDIO_LINUX_CRAS_UNIFIED_H_
12
13#include <cras_client.h>
14
15#include "base/compiler_specific.h"
16#include "media/audio/audio_io.h"
17#include "media/audio/audio_parameters.h"
18
19namespace media {
20
21class AudioManagerCras;
22
23// Implementation of AudioOuputStream for Chrome OS using the Chrome OS audio
24// server.
25// TODO(dgreid): This class is used for only output, either remove all the
26// relevant input code and change the class to CrasOutputStream or merge
27// cras_input.cc into this unified implementation.
28class MEDIA_EXPORT CrasUnifiedStream : public AudioOutputStream {
29 public:
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);
33
34  // The dtor is typically called by the AudioManager only and it is usually
35  // triggered by calling AudioUnifiedStream::Close().
36  virtual ~CrasUnifiedStream();
37
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;
45
46 private:
47  // Convert Latency in time to bytes.
48  uint32 GetBytesLatency(const struct timespec& latency);
49
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,
53                             uint8* input_samples,
54                             uint8* output_samples,
55                             unsigned int frames,
56                             const timespec* input_ts,
57                             const timespec* output_ts,
58                             void* arg);
59
60  // Handles notification that there was an error with the playback stream.
61  static int StreamError(cras_client* client,
62                         cras_stream_id_t stream_id,
63                         int err,
64                         void* arg);
65
66  // Chooses the correct audio callback based on stream direction.
67  uint32 DispatchCallback(size_t frames,
68                          uint8* input_samples,
69                          uint8* output_samples,
70                          const timespec* input_ts,
71                          const timespec* output_ts);
72
73  // Writes audio for a playback stream.
74  uint32 WriteAudio(size_t frames, uint8* buffer, const timespec* sample_ts);
75
76  // Deals with an error that occured in the stream.  Called from StreamError().
77  void NotifyStreamError(int err);
78
79  // The client used to communicate with the audio server.
80  cras_client* client_;
81
82  // ID of the playing stream.
83  cras_stream_id_t stream_id_;
84
85  // PCM parameters for the stream.
86  AudioParameters params_;
87
88  // Size of frame in bytes.
89  uint32 bytes_per_frame_;
90
91  // True if stream is playing.
92  bool is_playing_;
93
94  // Volume level from 0.0 to 1.0.
95  float volume_;
96
97  // Audio manager that created us.  Used to report that we've been closed.
98  AudioManagerCras* manager_;
99
100  // Callback to get audio samples.
101  AudioSourceCallback* source_callback_;
102
103  // Container for exchanging data with AudioSourceCallback::OnMoreData().
104  scoped_ptr<AudioBus> output_bus_;
105
106  // Direciton of the stream.
107  CRAS_STREAM_DIRECTION stream_direction_;
108
109  DISALLOW_COPY_AND_ASSIGN(CrasUnifiedStream);
110};
111
112}  // namespace media
113
114#endif  // MEDIA_AUDIO_LINUX_CRAS_UNIFIED_H_
115