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1 // Copyright (c) 2011 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 an audio output stream based on the PulseAudio asynchronous API. | |
6 // | |
7 // If the stream is successfully opened, Close() must be called before the | |
8 // stream is deleted as Close() is responsible for ensuring resource cleanup | |
9 // occurs. | |
10 // | |
11 // This object is designed so that all AudioOutputStream methods will be called | |
12 // on the same thread that created the object. | |
13 // | |
14 // WARNING: This object blocks on internal PulseAudio calls after Start() is | |
15 // invoked and repeatedly throughout playback as it waits for PulseAudio write | |
16 // callbacks to occur. | |
17 | |
18 #ifndef MEDIA_AUDIO_LINUX_PULSE_OUTPUT_H_ | |
19 #define MEDIA_AUDIO_LINUX_PULSE_OUTPUT_H_ | |
20 | |
21 #include <pulse/pulseaudio.h> | |
22 | |
23 #include <string> | |
24 | |
25 #include "base/message_loop.h" | |
vrk (LEFT CHROMIUM)
2011/08/16 18:19:24
nit: includes in ABC order
Well actually, just fo
slock
2011/08/17 21:43:14
Done.
| |
26 #include "base/memory/scoped_ptr.h" | |
27 #include "media/audio/audio_io.h" | |
28 #include "media/audio/audio_parameters.h" | |
vrk (LEFT CHROMIUM)
2011/08/16 18:19:24
Forward-declare AudioParameters instead of include
slock
2011/08/17 21:43:14
Done.
| |
29 | |
30 namespace media { | |
31 class SeekableBuffer; | |
32 } | |
33 | |
34 class AudioManagerLinux; | |
35 | |
36 class PulseAudioOutputStream : public AudioOutputStream { | |
37 public: | |
38 PulseAudioOutputStream(const AudioParameters& params, | |
39 AudioManagerLinux* manager, | |
40 MessageLoop* message_loop); | |
41 | |
42 virtual ~PulseAudioOutputStream(); | |
43 | |
44 // Implementation of AudioOutputStream. | |
45 virtual bool Open(); | |
46 virtual void Close(); | |
47 virtual void Start(AudioSourceCallback* callback); | |
48 virtual void Stop(); | |
49 virtual void SetVolume(double volume); | |
50 virtual void GetVolume(double* volume); | |
51 | |
52 private: | |
53 // PulseAudio Callbacks. | |
54 static void ContextStateCallback(pa_context* context, void* userdata); | |
55 static void WriteCallback(pa_stream* stream, size_t length, void* userdata); | |
56 | |
57 // PulseAudio mainloop iteration loop task function; used to avoid blocking | |
58 // the audio thread. | |
59 void WaitForWriteTask(); | |
60 | |
61 // Function to get another packet from the data source and write it into the | |
62 // client buffer. | |
63 void BufferPacketInClient(); | |
64 | |
65 // API for Proxying calls to the AudioSourceCallback provided during Start(). | |
66 uint32 RunDataCallback(uint8* dest, uint32 max_size, | |
67 AudioBuffersState buffers_state); | |
68 | |
69 // Close() helper function to free internal structs. | |
70 void Reset(); | |
71 | |
72 // Configuration constants from the constructor. Referencable by all threads | |
73 // since they are constants. | |
74 const ChannelLayout channel_layout_; | |
75 const uint32 channel_count_; | |
76 const pa_sample_format_t sample_format_; | |
77 const uint32 sample_rate_; | |
78 const uint32 bytes_per_frame_; | |
79 | |
80 // Audio manager that created us. Used to report that we've closed. | |
81 AudioManagerLinux* manager_; | |
82 | |
83 // PulseAudio API structs. | |
84 pa_context* pa_context_; | |
85 pa_mainloop* pa_mainloop_; | |
86 | |
87 // Handle to the actual PulseAudio playback stream. | |
88 pa_stream* playback_handle_; | |
89 | |
90 // Device configuration data. Populated after Open() completes. | |
91 uint32 packet_size_; | |
92 uint32 frames_per_packet_; | |
93 | |
94 // Internal buffer. | |
95 scoped_ptr<media::SeekableBuffer> client_buffer_; | |
96 bool source_exhausted_; | |
97 | |
98 // Float representation of volume from 0.0 to 1.0. | |
99 float volume_; | |
100 | |
101 // Flag indicating the code should stop reading from the data source or | |
102 // writing to the PulseAudio server. This is set because the device has | |
103 // entered an unrecoverable error state, or the Close() has executed. | |
104 bool stream_stopped_; | |
105 | |
106 // Whether or not PulseAudio has called the WriteCallback for the most recent | |
107 // set of pa_mainloop iterations. | |
108 bool write_callback_handled_; | |
109 | |
110 // Message loop used to post WaitForWriteTasks. Used to prevent blocking on | |
111 // the audio thread while waiting for PulseAudio write callbacks. | |
112 MessageLoop* message_loop_; | |
113 | |
114 // Allows us to run tasks on the PulseAudioOutputStream instance which are | |
115 // bound by its lifetime. | |
116 ScopedRunnableMethodFactory<PulseAudioOutputStream> method_factory_; | |
117 | |
118 // Callback to audio data source. | |
119 AudioSourceCallback* source_callback_; | |
120 | |
121 DISALLOW_COPY_AND_ASSIGN(PulseAudioOutputStream); | |
122 }; | |
123 | |
124 #endif // MEDIA_AUDIO_LINUX_PULSE_OUTPUT_H_ | |
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