FFmpeg  2.1.1
aacdec.c
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1 /*
2  * raw ADTS AAC demuxer
3  * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
4  * Copyright (c) 2009 Robert Swain ( rob opendot cl )
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include "libavutil/intreadwrite.h"
24 #include "avformat.h"
25 #include "internal.h"
26 #include "rawdec.h"
27 #include "id3v1.h"
28 #include "apetag.h"
29 
31 {
32  int max_frames = 0, first_frames = 0;
33  int fsize, frames;
34  const uint8_t *buf0 = p->buf;
35  const uint8_t *buf2;
36  const uint8_t *buf;
37  const uint8_t *end = buf0 + p->buf_size - 7;
38 
39  buf = buf0;
40 
41  for(; buf < end; buf= buf2+1) {
42  buf2 = buf;
43 
44  for(frames = 0; buf2 < end; frames++) {
45  uint32_t header = AV_RB16(buf2);
46  if((header&0xFFF6) != 0xFFF0)
47  break;
48  fsize = (AV_RB32(buf2 + 3) >> 13) & 0x1FFF;
49  if(fsize < 7)
50  break;
51  fsize = FFMIN(fsize, end - buf2);
52  buf2 += fsize;
53  }
54  max_frames = FFMAX(max_frames, frames);
55  if(buf == buf0)
56  first_frames= frames;
57  }
58  if (first_frames>=3) return AVPROBE_SCORE_EXTENSION + 1;
59  else if(max_frames>500)return AVPROBE_SCORE_EXTENSION;
60  else if(max_frames>=3) return AVPROBE_SCORE_EXTENSION / 2;
61  else if(max_frames>=1) return 1;
62  else return 0;
63 }
64 
66 {
67  AVStream *st;
68 
69  st = avformat_new_stream(s, NULL);
70  if (!st)
71  return AVERROR(ENOMEM);
72 
76 
77  ff_id3v1_read(s);
78  if (s->pb->seekable &&
79  !av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX)) {
80  int64_t cur = avio_tell(s->pb);
82  avio_seek(s->pb, cur, SEEK_SET);
83  }
84 
85  //LCM of all possible ADTS sample rates
86  avpriv_set_pts_info(st, 64, 1, 28224000);
87 
88  return 0;
89 }
90 
92  .name = "aac",
93  .long_name = NULL_IF_CONFIG_SMALL("raw ADTS AAC (Advanced Audio Coding)"),
94  .read_probe = adts_aac_probe,
95  .read_header = adts_aac_read_header,
96  .read_packet = ff_raw_read_partial_packet,
97  .flags = AVFMT_GENERIC_INDEX,
98  .extensions = "aac",
99  .raw_codec_id = AV_CODEC_ID_AAC,
100 };
const char * s
Definition: avisynth_c.h:668
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
AVDictionaryEntry * av_dict_get(AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags)
Get a dictionary entry with matching key.
Definition: dict.c:39
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:686
void ff_id3v1_read(AVFormatContext *s)
Read an ID3v1 tag.
Definition: id3v1.c:228
Format I/O context.
Definition: avformat.h:968
#define AV_RB16(x)
Definition: intreadwrite.h:232
uint8_t
static int adts_aac_read_header(AVFormatContext *s)
Definition: aacdec.c:65
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
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:248
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
AVInputFormat ff_aac_demuxer
Definition: aacdec.c:91
#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
int64_t ff_ape_parse_tag(AVFormatContext *s)
Read and parse an APE tag.
Definition: apetag.c:115
#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
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:117
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:341
#define FFMIN(a, b)
Definition: avcodec.h:925
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:199
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
AVIOContext * pb
I/O context.
Definition: avformat.h:1001
void * buf
Definition: avisynth_c.h:594
AVDictionary * metadata
Definition: avformat.h:1128
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
static int adts_aac_probe(AVProbeData *p)
Definition: aacdec.c:30
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 AV_RB32(x)
Definition: intreadwrite.h:258
#define AVERROR(e)
#define AV_DICT_IGNORE_SUFFIX
Definition: dict.h:68