FFmpeg
audio_fifo.h
Go to the documentation of this file.
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 "attributes.h"
31 #include "samplefmt.h"
32 
33 /**
34  * @addtogroup lavu_audio
35  * @{
36  *
37  * @defgroup lavu_audiofifo Audio FIFO Buffer
38  * @{
39  */
40 
41 /**
42  * Context for an Audio FIFO Buffer.
43  *
44  * - Operates at the sample level rather than the byte level.
45  * - Supports multiple channels with either planar or packed sample format.
46  * - Automatic reallocation when writing to a full buffer.
47  */
48 typedef struct AVAudioFifo AVAudioFifo;
49 
50 /**
51  * Free an AVAudioFifo.
52  *
53  * @param af AVAudioFifo to free
54  */
56 
57 /**
58  * Allocate an AVAudioFifo.
59  *
60  * @param sample_fmt sample format
61  * @param channels number of channels
62  * @param nb_samples initial allocation size, in samples
63  * @return newly allocated AVAudioFifo, or NULL on error
64  */
66  int nb_samples);
67 
68 /**
69  * Reallocate an AVAudioFifo.
70  *
71  * @param af AVAudioFifo to reallocate
72  * @param nb_samples new allocation size, in samples
73  * @return 0 if OK, or negative AVERROR code on failure
74  */
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 * const *data, int nb_samples);
95 
96 /**
97  * Peek 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 peek
105  * @return number of samples actually peek, or negative AVERROR code
106  * on failure. The number of samples actually peek 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_peek(const AVAudioFifo *af, void * const *data, int nb_samples);
111 
112 /**
113  * Peek data from an AVAudioFifo.
114  *
115  * @see enum AVSampleFormat
116  * The documentation for AVSampleFormat describes the data layout.
117  *
118  * @param af AVAudioFifo to read from
119  * @param data audio data plane pointers
120  * @param nb_samples number of samples to peek
121  * @param offset offset from current read position
122  * @return number of samples actually peek, or negative AVERROR code
123  * on failure. The number of samples actually peek will not
124  * be greater than nb_samples, and will only be less than
125  * nb_samples if av_audio_fifo_size is less than nb_samples.
126  */
127 int av_audio_fifo_peek_at(const AVAudioFifo *af, void * const *data,
128  int nb_samples, int offset);
129 
130 /**
131  * Read data from an AVAudioFifo.
132  *
133  * @see enum AVSampleFormat
134  * The documentation for AVSampleFormat describes the data layout.
135  *
136  * @param af AVAudioFifo to read from
137  * @param data audio data plane pointers
138  * @param nb_samples number of samples to read
139  * @return number of samples actually read, or negative AVERROR code
140  * on failure. The number of samples actually read will not
141  * be greater than nb_samples, and will only be less than
142  * nb_samples if av_audio_fifo_size is less than nb_samples.
143  */
144 int av_audio_fifo_read(AVAudioFifo *af, void * const *data, int nb_samples);
145 
146 /**
147  * Drain data from an AVAudioFifo.
148  *
149  * Removes the data without reading it.
150  *
151  * @param af AVAudioFifo to drain
152  * @param nb_samples number of samples to drain
153  * @return 0 if OK, or negative AVERROR code on failure
154  */
156 
157 /**
158  * Reset the AVAudioFifo buffer.
159  *
160  * This empties all data in the buffer.
161  *
162  * @param af AVAudioFifo to reset
163  */
165 
166 /**
167  * Get the current number of samples in the AVAudioFifo available for reading.
168  *
169  * @param af the AVAudioFifo to query
170  * @return number of samples available for reading
171  */
173 
174 /**
175  * Get the current number of samples in the AVAudioFifo available for writing.
176  *
177  * @param af the AVAudioFifo to query
178  * @return number of samples available for writing
179  */
181 
182 /**
183  * @}
184  * @}
185  */
186 
187 #endif /* AVUTIL_AUDIO_FIFO_H */
av_audio_fifo_free
void av_audio_fifo_free(AVAudioFifo *af)
Free an AVAudioFifo.
Definition: audio_fifo.c:48
av_audio_fifo_write
int av_audio_fifo_write(AVAudioFifo *af, void *const *data, int nb_samples)
Write data to an AVAudioFifo.
Definition: audio_fifo.c:119
av_audio_fifo_realloc
av_warn_unused_result int av_audio_fifo_realloc(AVAudioFifo *af, int nb_samples)
Reallocate an AVAudioFifo.
Definition: audio_fifo.c:99
data
const char data[16]
Definition: mxf.c:149
AVAudioFifo::nb_samples
int nb_samples
number of samples currently in the FIFO
Definition: audio_fifo.c:40
AVAudioFifo
Context for an Audio FIFO Buffer.
Definition: audio_fifo.c:37
av_audio_fifo_drain
int av_audio_fifo_drain(AVAudioFifo *af, int nb_samples)
Drain data from an AVAudioFifo.
Definition: audio_fifo.c:195
samplefmt.h
channels
channels
Definition: aptx.h:31
av_audio_fifo_alloc
AVAudioFifo * av_audio_fifo_alloc(enum AVSampleFormat sample_fmt, int channels, int nb_samples)
Allocate an AVAudioFifo.
Definition: audio_fifo.c:62
av_audio_fifo_read
int av_audio_fifo_read(AVAudioFifo *af, void *const *data, int nb_samples)
Read data from an AVAudioFifo.
Definition: audio_fifo.c:175
av_audio_fifo_peek
int av_audio_fifo_peek(const AVAudioFifo *af, void *const *data, int nb_samples)
Peek data from an AVAudioFifo.
Definition: audio_fifo.c:145
offset
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset
Definition: writing_filters.txt:86
attributes.h
av_audio_fifo_size
int av_audio_fifo_size(AVAudioFifo *af)
Get the current number of samples in the AVAudioFifo available for reading.
Definition: audio_fifo.c:222
av_warn_unused_result
#define av_warn_unused_result
Definition: attributes.h:64
AVSampleFormat
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:55
AVAudioFifo::sample_fmt
enum AVSampleFormat sample_fmt
sample format
Definition: audio_fifo.c:44
av_audio_fifo_space
int av_audio_fifo_space(AVAudioFifo *af)
Get the current number of samples in the AVAudioFifo available for writing.
Definition: audio_fifo.c:227
av_audio_fifo_reset
void av_audio_fifo_reset(AVAudioFifo *af)
Reset the AVAudioFifo buffer.
Definition: audio_fifo.c:212
av_audio_fifo_peek_at
int av_audio_fifo_peek_at(const AVAudioFifo *af, void *const *data, int nb_samples, int offset)
Peek data from an AVAudioFifo.
Definition: audio_fifo.c:150