1 : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 : /* vim:set ts=2 sw=2 sts=2 et cindent: */
3 : /* ***** BEGIN LICENSE BLOCK *****
4 : * Version: MPL 1.1/GPL 2.0/LGPL 2.1
5 : *
6 : * The contents of this file are subject to the Mozilla Public License Version
7 : * 1.1 (the "License"); you may not use this file except in compliance with
8 : * the License. You may obtain a copy of the License at
9 : * http://www.mozilla.org/MPL/
10 : *
11 : * Software distributed under the License is distributed on an "AS IS" basis,
12 : * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13 : * for the specific language governing rights and limitations under the
14 : * License.
15 : *
16 : * The Original Code is Mozilla code.
17 : *
18 : * The Initial Developer of the Original Code is the Mozilla Corporation.
19 : * Portions created by the Initial Developer are Copyright (C) 2007
20 : * the Initial Developer. All Rights Reserved.
21 : *
22 : * Contributor(s):
23 : * Chris Double <chris.double@double.co.nz>
24 : *
25 : * Alternatively, the contents of this file may be used under the terms of
26 : * either the GNU General Public License Version 2 or later (the "GPL"), or
27 : * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
28 : * in which case the provisions of the GPL or the LGPL are applicable instead
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30 : * under the terms of either the GPL or the LGPL, and not to allow others to
31 : * use your version of this file under the terms of the MPL, indicate your
32 : * decision by deleting the provisions above and replace them with the notice
33 : * and other provisions required by the GPL or the LGPL. If you do not delete
34 : * the provisions above, a recipient may use your version of this file under
35 : * the terms of any one of the MPL, the GPL or the LGPL.
36 : *
37 : * ***** END LICENSE BLOCK ***** */
38 : #if !defined(nsAudioStream_h_)
39 : #define nsAudioStream_h_
40 :
41 : #include "nscore.h"
42 : #include "nsISupportsImpl.h"
43 : #include "nsIThread.h"
44 : #include "nsAutoPtr.h"
45 :
46 : class nsAudioStream : public nsISupports
47 : {
48 : public:
49 :
50 : enum SampleFormat
51 : {
52 : FORMAT_U8,
53 : FORMAT_S16_LE,
54 : FORMAT_FLOAT32
55 : };
56 :
57 0 : nsAudioStream()
58 : : mRate(0),
59 : mChannels(0),
60 0 : mFormat(FORMAT_S16_LE)
61 0 : {}
62 :
63 : virtual ~nsAudioStream();
64 :
65 : // Initialize Audio Library. Some Audio backends require initializing the
66 : // library before using it.
67 : static void InitLibrary();
68 :
69 : // Shutdown Audio Library. Some Audio backends require shutting down the
70 : // library after using it.
71 : static void ShutdownLibrary();
72 :
73 : // Thread that is shared between audio streams.
74 : // This may return null in the child process
75 : nsIThread *GetThread();
76 :
77 : // AllocateStream will return either a local stream or a remoted stream
78 : // depending on where you call it from. If you call this from a child process,
79 : // you may receive an implementation which forwards to a compositing process.
80 : static nsAudioStream* AllocateStream();
81 :
82 : // Initialize the audio stream. aNumChannels is the number of audio
83 : // channels (1 for mono, 2 for stereo, etc) and aRate is the sample rate
84 : // (22050Hz, 44100Hz, etc).
85 : // Unsafe to call with the decoder monitor held.
86 : virtual nsresult Init(PRInt32 aNumChannels, PRInt32 aRate, SampleFormat aFormat) = 0;
87 :
88 : // Closes the stream. All future use of the stream is an error.
89 : // Unsafe to call with the decoder monitor held.
90 : virtual void Shutdown() = 0;
91 :
92 : // Write audio data to the audio hardware. aBuf is an array of frames in
93 : // the format specified by mFormat of length aCount. If aFrames is larger
94 : // than the result of Available(), the write will block until sufficient
95 : // buffer space is available.
96 : virtual nsresult Write(const void* aBuf, PRUint32 aFrames) = 0;
97 :
98 : // Return the number of audio frames that can be written without blocking.
99 : virtual PRUint32 Available() = 0;
100 :
101 : // Set the current volume of the audio playback. This is a value from
102 : // 0 (meaning muted) to 1 (meaning full volume).
103 : virtual void SetVolume(double aVolume) = 0;
104 :
105 : // Block until buffered audio data has been consumed.
106 : // Unsafe to call with the decoder monitor held.
107 : virtual void Drain() = 0;
108 :
109 : // Pause audio playback
110 : virtual void Pause() = 0;
111 :
112 : // Resume audio playback
113 : virtual void Resume() = 0;
114 :
115 : // Return the position in microseconds of the audio frame being played by
116 : // the audio hardware.
117 : virtual PRInt64 GetPosition() = 0;
118 :
119 : // Return the position, measured in audio frames played since the stream
120 : // was opened, of the audio hardware.
121 : virtual PRInt64 GetPositionInFrames() = 0;
122 :
123 : // Returns true when the audio stream is paused.
124 : virtual bool IsPaused() = 0;
125 :
126 : // Returns the minimum number of audio frames which must be written before
127 : // you can be sure that something will be played.
128 : // Unsafe to call with the decoder monitor held.
129 : virtual PRInt32 GetMinWriteSize() = 0;
130 :
131 : int GetRate() { return mRate; }
132 : int GetChannels() { return mChannels; }
133 : SampleFormat GetFormat() { return mFormat; }
134 :
135 : protected:
136 : nsCOMPtr<nsIThread> mAudioPlaybackThread;
137 : int mRate;
138 : int mChannels;
139 : SampleFormat mFormat;
140 : };
141 :
142 : #endif
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