FFmpeg
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 #define LOAS_SYNC_WORD 0x2b7
29 
30 static int loas_probe(const AVProbeData *p)
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 - 3;
38  buf = buf0;
39 
40  for (; buf < end; buf = buf2 + 1) {
41  buf2 = buf;
42 
43  for (frames = 0; buf2 < end; frames++) {
44  uint32_t header = AV_RB24(buf2);
45  if ((header >> 13) != LOAS_SYNC_WORD)
46  break;
47  fsize = (header & 0x1FFF) + 3;
48  if (fsize < 7)
49  break;
50  fsize = FFMIN(fsize, end - buf2);
51  buf2 += fsize;
52  }
53  max_frames = FFMAX(max_frames, frames);
54  if (buf == buf0)
55  first_frames = frames;
56  }
57 
58  if (first_frames >= 3)
59  return AVPROBE_SCORE_EXTENSION + 1;
60  else if (max_frames > 100)
62  else if (max_frames >= 3)
63  return AVPROBE_SCORE_EXTENSION / 2;
64  else
65  return 0;
66 }
67 
69 {
70  AVStream *st;
71 
72  st = avformat_new_stream(s, NULL);
73  if (!st)
74  return AVERROR(ENOMEM);
75 
79 
80  //LCM of all possible AAC sample rates
81  avpriv_set_pts_info(st, 64, 1, 28224000);
82 
83  return 0;
84 }
85 
88  .name = "loas",
89  .long_name = NULL_IF_CONFIG_SMALL("LOAS AudioSyncStream"),
90  .read_probe = loas_probe,
91  .read_header = loas_read_header,
92  .read_packet = ff_raw_read_partial_packet,
93  .flags= AVFMT_GENERIC_INDEX,
94  .raw_codec_id = AV_CODEC_ID_AAC_LATM,
95  .priv_data_size = sizeof(FFRawDemuxerContext),
96  .priv_class = &loas_demuxer_class,
97 };
#define NULL
Definition: coverity.c:32
static int loas_read_header(AVFormatContext *s)
Definition: loasdec.c:68
static int loas_probe(const AVProbeData *p)
Definition: loasdec.c:30
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:4892
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3957
if it could not because there are no more frames
Format I/O context.
Definition: avformat.h:1358
uint8_t
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
enum AVStreamParseType need_parsing
Definition: avformat.h:1099
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4465
#define LOAS_SYNC_WORD
Definition: loasdec.c:28
static const uint8_t header[24]
Definition: sdr2.c:67
full parsing and repack with timestamp and position generation by parser for raw this assumes that ea...
Definition: avformat.h:804
int ff_raw_read_partial_packet(AVFormatContext *s, AVPacket *pkt)
Definition: rawdec.c:35
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
ff_const59 struct AVInputFormat * iformat
The input container format.
Definition: avformat.h:1370
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3953
#define FFMAX(a, b)
Definition: common.h:94
#define FF_RAW_DEMUXER_CLASS(name)
Definition: rawdec.h:55
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
common internal API header
#define FFMIN(a, b)
Definition: common.h:96
#define s(width, name)
Definition: cbs_vp9.c:257
Stream structure.
Definition: avformat.h:881
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_RB24
Definition: bytestream.h:87
void * buf
Definition: avisynth_c.h:766
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:468
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:456
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
int raw_codec_id
Raw demuxers store their codec ID here.
Definition: avformat.h:700
Main libavformat public API header.
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:654
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
static int64_t fsize(FILE *f)
Definition: audiomatch.c:28
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
AVInputFormat ff_loas_demuxer
Definition: loasdec.c:87