Libav
sndio_dec.c
Go to the documentation of this file.
1 /*
2  * sndio play and grab interface
3  * Copyright (c) 2010 Jacob Meuser
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include <stdint.h>
23 #include <sndio.h>
24 
25 #include "libavformat/avformat.h"
26 #include "libavformat/internal.h"
27 #include "libavutil/opt.h"
28 #include "libavutil/time.h"
29 
30 #include "sndio_common.h"
31 
33 {
34  SndioData *s = s1->priv_data;
35  AVStream *st;
36  int ret;
37 
38  st = avformat_new_stream(s1, NULL);
39  if (!st)
40  return AVERROR(ENOMEM);
41 
42  ret = ff_sndio_open(s1, 0, s1->filename);
43  if (ret < 0)
44  return ret;
45 
46  /* take real parameters */
48  st->codec->codec_id = s->codec_id;
49  st->codec->sample_rate = s->sample_rate;
50  st->codec->channels = s->channels;
51 
52  avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
53 
54  return 0;
55 }
56 
58 {
59  SndioData *s = s1->priv_data;
60  int64_t bdelay, cur_time;
61  int ret;
62 
63  if ((ret = av_new_packet(pkt, s->buffer_size)) < 0)
64  return ret;
65 
66  ret = sio_read(s->hdl, pkt->data, pkt->size);
67  if (ret == 0 || sio_eof(s->hdl)) {
68  av_free_packet(pkt);
69  return AVERROR_EOF;
70  }
71 
72  pkt->size = ret;
73  s->softpos += ret;
74 
75  /* compute pts of the start of the packet */
76  cur_time = av_gettime();
77 
78  bdelay = ret + s->hwpos - s->softpos;
79 
80  /* convert to pts */
81  pkt->pts = cur_time - ((bdelay * 1000000) /
82  (s->bps * s->channels * s->sample_rate));
83 
84  return 0;
85 }
86 
88 {
89  SndioData *s = s1->priv_data;
90 
91  ff_sndio_close(s);
92 
93  return 0;
94 }
95 
96 static const AVOption options[] = {
97  { "sample_rate", "", offsetof(SndioData, sample_rate), AV_OPT_TYPE_INT, {.i64 = 48000}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
98  { "channels", "", offsetof(SndioData, channels), AV_OPT_TYPE_INT, {.i64 = 2}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
99  { NULL },
100 };
101 
102 static const AVClass sndio_demuxer_class = {
103  .class_name = "sndio indev",
104  .item_name = av_default_item_name,
105  .option = options,
106  .version = LIBAVUTIL_VERSION_INT,
107 };
108 
110  .name = "sndio",
111  .long_name = NULL_IF_CONFIG_SMALL("sndio audio capture"),
112  .priv_data_size = sizeof(SndioData),
116  .flags = AVFMT_NOFILE,
117  .priv_class = &sndio_demuxer_class,
118 };
void av_free_packet(AVPacket *pkt)
Free a packet.
Definition: avpacket.c:243
AVOption.
Definition: opt.h:234
static const AVOption options[]
Definition: sndio_dec.c:96
int channels
Definition: sndio_common.h:41
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:2829
int size
Definition: avcodec.h:974
int ff_sndio_close(SndioData *s)
Definition: sndio_common.c:112
static int audio_read_packet(AVFormatContext *s1, AVPacket *pkt)
Definition: sndio_dec.c:57
Format I/O context.
Definition: avformat.h:922
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:38
enum AVCodecID codec_id
Definition: sndio_common.h:34
#define av_cold
Definition: attributes.h:66
AVOptions.
int sample_rate
Definition: sndio_common.h:42
static const AVClass sndio_demuxer_class
Definition: sndio_dec.c:102
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:2521
uint8_t * data
Definition: avcodec.h:973
static int flags
Definition: log.c:44
#define AVERROR_EOF
End of file.
Definition: error.h:51
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:145
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:81
AVInputFormat ff_sndio_demuxer
Definition: sndio_dec.c:109
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:150
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:718
char filename[1024]
input or output filename
Definition: avformat.h:998
static av_cold int audio_read_close(AVFormatContext *s1)
Definition: sndio_dec.c:87
LIBAVUTIL_VERSION_INT
Definition: eval.c:55
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:544
int64_t av_gettime(void)
Get the current time in microseconds.
Definition: time.c:37
Stream structure.
Definition: avformat.h:699
NULL
Definition: eval.c:55
enum AVMediaType codec_type
Definition: avcodec.h:1058
enum AVCodecID codec_id
Definition: avcodec.h:1067
int sample_rate
samples per second
Definition: avcodec.h:1791
av_default_item_name
Definition: dnxhdenc.c:52
int buffer_size
Definition: sndio_common.h:39
static int read_packet(AVFormatContext *ctx, AVPacket *pkt)
Definition: libcdio.c:114
Describe the class of an AVClass context structure.
Definition: log.h:33
#define AV_OPT_FLAG_DECODING_PARAM
a generic parameter which can be set by the user for demuxing or decoding
Definition: opt.h:265
int64_t hwpos
Definition: sndio_common.h:35
int64_t softpos
Definition: sndio_common.h:36
struct sio_hdl * hdl
Definition: sndio_common.h:33
Main libavformat public API header.
av_cold int ff_sndio_open(AVFormatContext *s1, int is_output, const char *audio_device)
Definition: sndio_common.c:36
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:409
int channels
number of audio channels
Definition: avcodec.h:1792
void * priv_data
Format private data.
Definition: avformat.h:950
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:525
static av_cold int audio_read_header(AVFormatContext *s1)
Definition: sndio_dec.c:32
This structure stores compressed data.
Definition: avcodec.h:950
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:966