Libav
audio.c
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1 /*
2  * This file is part of Libav.
3  *
4  * Libav is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * Libav is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with Libav; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
20 #include "libavutil/common.h"
21 
22 #include "audio.h"
23 #include "avfilter.h"
24 #include "internal.h"
25 
27 {
28  return ff_get_audio_buffer(link->dst->outputs[0], nb_samples);
29 }
30 
32 {
33  AVFrame *frame = av_frame_alloc();
35  int ret;
36 
37  if (!frame)
38  return NULL;
39 
40  frame->nb_samples = nb_samples;
41  frame->format = link->format;
42  frame->channel_layout = link->channel_layout;
43  frame->sample_rate = link->sample_rate;
44  ret = av_frame_get_buffer(frame, 0);
45  if (ret < 0) {
46  av_frame_free(&frame);
47  return NULL;
48  }
49 
50  av_samples_set_silence(frame->extended_data, 0, nb_samples, channels,
51  link->format);
52 
53 
54  return frame;
55 }
56 
57 AVFrame *ff_get_audio_buffer(AVFilterLink *link, int nb_samples)
58 {
59  AVFrame *ret = NULL;
60 
61  if (link->dstpad->get_audio_buffer)
62  ret = link->dstpad->get_audio_buffer(link, nb_samples);
63 
64  if (!ret)
65  ret = ff_default_get_audio_buffer(link, nb_samples);
66 
67  return ret;
68 }
This structure describes decoded (raw) audio or video data.
Definition: frame.h:140
Main libavfilter public API header.
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:68
int av_samples_set_silence(uint8_t **audio_data, int offset, int nb_samples, int nb_channels, enum AVSampleFormat sample_fmt)
Fill an audio buffer with silence.
Definition: samplefmt.c:206
AVFrame * ff_get_audio_buffer(AVFilterLink *link, int nb_samples)
Request an audio samples buffer with a specific set of permissions.
Definition: audio.c:57
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:80
int av_get_channel_layout_nb_channels(uint64_t channel_layout)
Return the number of channels in the channel layout.
uint64_t channel_layout
Channel layout of the audio data.
Definition: frame.h:294
audio channel layout utility functions
AVFrame * ff_null_get_audio_buffer(AVFilterLink *link, int nb_samples)
get_audio_buffer() handler for filters which simply pass audio along
Definition: audio.c:26
int format
format of the frame, -1 if unknown or unset Values correspond to enum AVPixelFormat for video frames...
Definition: frame.h:191
NULL
Definition: eval.c:55
AVFrame *(* get_audio_buffer)(AVFilterLink *link, int nb_samples)
Callback function to get an audio buffer.
Definition: internal.h:62
int sample_rate
Sample rate of the audio data.
Definition: frame.h:289
AVFilterLink ** outputs
array of pointers to output links
Definition: avfilter.h:274
int av_frame_get_buffer(AVFrame *frame, int align)
Allocate new buffer(s) for audio or video data.
Definition: frame.c:186
common internal and external API header
AVFrame * ff_default_get_audio_buffer(AVFilterLink *link, int nb_samples)
default handler for get_audio_buffer() for audio inputs
Definition: audio.c:31
internal API functions
uint8_t ** extended_data
pointers to the data planes/channels.
Definition: frame.h:174
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:184