FFmpeg  2.1.1
loasdec.c
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1 /*
2  * LOAS AudioSyncStream demuxer
3  * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
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 #include "libavutil/intreadwrite.h"
23 #include "libavutil/internal.h"
24 #include "avformat.h"
25 #include "internal.h"
26 #include "rawdec.h"
27 
28 static int loas_probe(AVProbeData *p)
29 {
30  int max_frames = 0, first_frames = 0;
31  int fsize, frames;
32  const uint8_t *buf0 = p->buf;
33  const uint8_t *buf2;
34  const uint8_t *buf;
35  const uint8_t *end = buf0 + p->buf_size - 3;
36  buf = buf0;
37 
38  for(; buf < end; buf= buf2+1) {
39  buf2 = buf;
40 
41  for(frames = 0; buf2 < end; frames++) {
42  uint32_t header = AV_RB24(buf2);
43  if((header >> 13) != 0x2B7)
44  break;
45  fsize = (header & 0x1FFF) + 3;
46  if(fsize < 7)
47  break;
48  fsize = FFMIN(fsize, end - buf2);
49  buf2 += fsize;
50  }
51  max_frames = FFMAX(max_frames, frames);
52  if(buf == buf0)
53  first_frames= frames;
54  }
55  if (first_frames>=3) return AVPROBE_SCORE_EXTENSION+1;
56  else if(max_frames>100)return AVPROBE_SCORE_EXTENSION;
57  else if(max_frames>=3) return AVPROBE_SCORE_EXTENSION / 2;
58  else return 0;
59 }
60 
62 {
63  AVStream *st;
64 
65  st = avformat_new_stream(s, NULL);
66  if (!st)
67  return AVERROR(ENOMEM);
68 
72 
73  //LCM of all possible AAC sample rates
74  avpriv_set_pts_info(st, 64, 1, 28224000);
75 
76  return 0;
77 }
78 
80  .name = "loas",
81  .long_name = NULL_IF_CONFIG_SMALL("LOAS AudioSyncStream"),
82  .read_probe = loas_probe,
83  .read_header = loas_read_header,
84  .read_packet = ff_raw_read_partial_packet,
85  .flags= AVFMT_GENERIC_INDEX,
86  .raw_codec_id = AV_CODEC_ID_AAC_LATM,
87 };
const char * s
Definition: avisynth_c.h:668
static int loas_read_header(AVFormatContext *s)
Definition: loasdec.c:61
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:478
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:3922
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:686
Format I/O context.
Definition: avformat.h:968
uint8_t
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:67
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:336
enum AVStreamParseType need_parsing
Definition: avformat.h:812
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:3348
int ff_raw_read_partial_packet(AVFormatContext *s, AVPacket *pkt)
Definition: rawdec.c:34
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:151
struct AVInputFormat * iformat
Can only be iformat or oformat, not both at the same time.
Definition: avformat.h:981
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:355
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:337
common internal API header
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:341
#define FFMIN(a, b)
Definition: avcodec.h:925
Stream structure.
Definition: avformat.h:667
enum AVMediaType codec_type
Definition: avcodec.h:1154
#define FFMAX(a, b)
Definition: avcodec.h:923
enum AVCodecID codec_id
Definition: avcodec.h:1157
static int loas_probe(AVProbeData *p)
Definition: loasdec.c:28
void * buf
Definition: avisynth_c.h:594
#define AV_RB24(x)
Definition: intreadwrite.h:436
This structure contains the data a format has to probe a file.
Definition: avformat.h:334
int raw_codec_id
Raw demuxers store their codec ID here.
Definition: avformat.h:517
Main libavformat public API header.
full parsing and repack with timestamp and position generation by parser for raw this assumes that ea...
Definition: avformat.h:603
#define AVERROR(e)
AVInputFormat ff_loas_demuxer
Definition: loasdec.c:79