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audio_fifo.h
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1 /*
2  * Audio FIFO
3  * Copyright (c) 2012 Justin Ruggles <justin.ruggles@gmail.com>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * Audio FIFO Buffer
25  */
26 
27 #ifndef AVUTIL_AUDIO_FIFO_H
28 #define AVUTIL_AUDIO_FIFO_H
29 
30 #include "avutil.h"
31 #include "fifo.h"
32 #include "samplefmt.h"
33 
34 /**
35  * @addtogroup lavu_audio
36  * @{
37  *
38  * @defgroup lavu_audiofifo Audio FIFO Buffer
39  * @{
40  */
41 
42 /**
43  * Context for an Audio FIFO Buffer.
44  *
45  * - Operates at the sample level rather than the byte level.
46  * - Supports multiple channels with either planar or packed sample format.
47  * - Automatic reallocation when writing to a full buffer.
48  */
49 typedef struct AVAudioFifo AVAudioFifo;
50 
51 /**
52  * Free an AVAudioFifo.
53  *
54  * @param af AVAudioFifo to free
55  */
57 
58 /**
59  * Allocate an AVAudioFifo.
60  *
61  * @param sample_fmt sample format
62  * @param channels number of channels
63  * @param nb_samples initial allocation size, in samples
64  * @return newly allocated AVAudioFifo, or NULL on error
65  */
67  int nb_samples);
68 
69 /**
70  * Reallocate an AVAudioFifo.
71  *
72  * @param af AVAudioFifo to reallocate
73  * @param nb_samples new allocation size, in samples
74  * @return 0 if OK, or negative AVERROR code on failure
75  */
77 
78 /**
79  * Write data to an AVAudioFifo.
80  *
81  * The AVAudioFifo will be reallocated automatically if the available space
82  * is less than nb_samples.
83  *
84  * @see enum AVSampleFormat
85  * The documentation for AVSampleFormat describes the data layout.
86  *
87  * @param af AVAudioFifo to write to
88  * @param data audio data plane pointers
89  * @param nb_samples number of samples to write
90  * @return number of samples actually written, or negative AVERROR
91  * code on failure. If successful, the number of samples
92  * actually written will always be nb_samples.
93  */
94 int av_audio_fifo_write(AVAudioFifo *af, void **data, int nb_samples);
95 
96 /**
97  * Read data from an AVAudioFifo.
98  *
99  * @see enum AVSampleFormat
100  * The documentation for AVSampleFormat describes the data layout.
101  *
102  * @param af AVAudioFifo to read from
103  * @param data audio data plane pointers
104  * @param nb_samples number of samples to read
105  * @return number of samples actually read, or negative AVERROR code
106  * on failure. The number of samples actually read will not
107  * be greater than nb_samples, and will only be less than
108  * nb_samples if av_audio_fifo_size is less than nb_samples.
109  */
110 int av_audio_fifo_read(AVAudioFifo *af, void **data, int nb_samples);
111 
112 /**
113  * Drain data from an AVAudioFifo.
114  *
115  * Removes the data without reading it.
116  *
117  * @param af AVAudioFifo to drain
118  * @param nb_samples number of samples to drain
119  * @return 0 if OK, or negative AVERROR code on failure
120  */
122 
123 /**
124  * Reset the AVAudioFifo buffer.
125  *
126  * This empties all data in the buffer.
127  *
128  * @param af AVAudioFifo to reset
129  */
131 
132 /**
133  * Get the current number of samples in the AVAudioFifo available for reading.
134  *
135  * @param af the AVAudioFifo to query
136  * @return number of samples available for reading
137  */
139 
140 /**
141  * Get the current number of samples in the AVAudioFifo available for writing.
142  *
143  * @param af the AVAudioFifo to query
144  * @return number of samples available for writing
145  */
147 
148 /**
149  * @}
150  * @}
151  */
152 
153 #endif /* AVUTIL_AUDIO_FIFO_H */