FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
audio_fifo.c
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
25  */
26 
27 #include "avutil.h"
28 #include "audio_fifo.h"
29 #include "common.h"
30 #include "fifo.h"
31 #include "mem.h"
32 #include "samplefmt.h"
33 
34 struct AVAudioFifo {
35  AVFifoBuffer **buf; /**< single buffer for interleaved, per-channel buffers for planar */
36  int nb_buffers; /**< number of buffers */
37  int nb_samples; /**< number of samples currently in the FIFO */
38  int allocated_samples; /**< current allocated size, in samples */
39 
40  int channels; /**< number of channels */
41  enum AVSampleFormat sample_fmt; /**< sample format */
42  int sample_size; /**< size, in bytes, of one sample in a buffer */
43 };
44 
46 {
47  if (af) {
48  if (af->buf) {
49  int i;
50  for (i = 0; i < af->nb_buffers; i++) {
51  if (af->buf[i])
52  av_fifo_free(af->buf[i]);
53  }
54  av_free(af->buf);
55  }
56  av_free(af);
57  }
58 }
59 
60 AVAudioFifo *av_audio_fifo_alloc(enum AVSampleFormat sample_fmt, int channels,
61  int nb_samples)
62 {
63  AVAudioFifo *af;
64  int buf_size, i;
65 
66  /* get channel buffer size (also validates parameters) */
67  if (av_samples_get_buffer_size(&buf_size, channels, nb_samples, sample_fmt, 1) < 0)
68  return NULL;
69 
70  af = av_mallocz(sizeof(*af));
71  if (!af)
72  return NULL;
73 
74  af->channels = channels;
75  af->sample_fmt = sample_fmt;
76  af->sample_size = buf_size / nb_samples;
77  af->nb_buffers = av_sample_fmt_is_planar(sample_fmt) ? channels : 1;
78 
79  af->buf = av_mallocz_array(af->nb_buffers, sizeof(*af->buf));
80  if (!af->buf)
81  goto error;
82 
83  for (i = 0; i < af->nb_buffers; i++) {
84  af->buf[i] = av_fifo_alloc(buf_size);
85  if (!af->buf[i])
86  goto error;
87  }
88  af->allocated_samples = nb_samples;
89 
90  return af;
91 
92 error:
94  return NULL;
95 }
96 
97 int av_audio_fifo_realloc(AVAudioFifo *af, int nb_samples)
98 {
99  int i, ret, buf_size;
100 
101  if ((ret = av_samples_get_buffer_size(&buf_size, af->channels, nb_samples,
102  af->sample_fmt, 1)) < 0)
103  return ret;
104 
105  for (i = 0; i < af->nb_buffers; i++) {
106  if ((ret = av_fifo_realloc2(af->buf[i], buf_size)) < 0)
107  return ret;
108  }
109  af->allocated_samples = nb_samples;
110  return 0;
111 }
112 
113 int av_audio_fifo_write(AVAudioFifo *af, void **data, int nb_samples)
114 {
115  int i, ret, size;
116 
117  /* automatically reallocate buffers if needed */
118  if (av_audio_fifo_space(af) < nb_samples) {
119  int current_size = av_audio_fifo_size(af);
120  /* check for integer overflow in new size calculation */
121  if (INT_MAX / 2 - current_size < nb_samples)
122  return AVERROR(EINVAL);
123  /* reallocate buffers */
124  if ((ret = av_audio_fifo_realloc(af, 2 * (current_size + nb_samples))) < 0)
125  return ret;
126  }
127 
128  size = nb_samples * af->sample_size;
129  for (i = 0; i < af->nb_buffers; i++) {
130  ret = av_fifo_generic_write(af->buf[i], data[i], size, NULL);
131  if (ret != size)
132  return AVERROR_BUG;
133  }
134  af->nb_samples += nb_samples;
135 
136  return nb_samples;
137 }
138 
139 int av_audio_fifo_read(AVAudioFifo *af, void **data, int nb_samples)
140 {
141  int i, ret, size;
142 
143  if (nb_samples < 0)
144  return AVERROR(EINVAL);
145  nb_samples = FFMIN(nb_samples, af->nb_samples);
146  if (!nb_samples)
147  return 0;
148 
149  size = nb_samples * af->sample_size;
150  for (i = 0; i < af->nb_buffers; i++) {
151  if ((ret = av_fifo_generic_read(af->buf[i], data[i], size, NULL)) < 0)
152  return AVERROR_BUG;
153  }
154  af->nb_samples -= nb_samples;
155 
156  return nb_samples;
157 }
158 
159 int av_audio_fifo_drain(AVAudioFifo *af, int nb_samples)
160 {
161  int i, size;
162 
163  if (nb_samples < 0)
164  return AVERROR(EINVAL);
165  nb_samples = FFMIN(nb_samples, af->nb_samples);
166 
167  if (nb_samples) {
168  size = nb_samples * af->sample_size;
169  for (i = 0; i < af->nb_buffers; i++)
170  av_fifo_drain(af->buf[i], size);
171  af->nb_samples -= nb_samples;
172  }
173  return 0;
174 }
175 
177 {
178  int i;
179 
180  for (i = 0; i < af->nb_buffers; i++)
181  av_fifo_reset(af->buf[i]);
182 
183  af->nb_samples = 0;
184 }
185 
187 {
188  return af->nb_samples;
189 }
190 
192 {
193  return af->allocated_samples - af->nb_samples;
194 }