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astdec.c
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1 /*
2  * AST demuxer
3  * Copyright (c) 2012 Paul B Mahol
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 
23 #include "libavutil/intreadwrite.h"
24 #include "avformat.h"
25 #include "internal.h"
26 #include "ast.h"
27 
28 static int ast_probe(AVProbeData *p)
29 {
30  if (AV_RL32(p->buf) != MKTAG('S','T','R','M'))
31  return 0;
32 
33  if (!AV_RB16(p->buf + 10) ||
34  !AV_RB16(p->buf + 12) || AV_RB16(p->buf + 12) > 256 ||
35  !AV_RB32(p->buf + 16) || AV_RB32(p->buf + 16) > 8*48000)
36  return AVPROBE_SCORE_MAX / 8;
37 
38  return AVPROBE_SCORE_MAX / 3 * 2;
39 }
40 
42 {
43  int depth;
44  AVStream *st;
45 
46  st = avformat_new_stream(s, NULL);
47  if (!st)
48  return AVERROR(ENOMEM);
49 
50  avio_skip(s->pb, 8);
53 
54  depth = avio_rb16(s->pb);
55  if (depth != 16) {
56  avpriv_request_sample(s, "depth %d", depth);
57  return AVERROR_INVALIDDATA;
58  }
59 
60  st->codecpar->channels = avio_rb16(s->pb);
61  if (!st->codecpar->channels)
62  return AVERROR_INVALIDDATA;
63 
64  if (st->codecpar->channels == 2)
66  else if (st->codecpar->channels == 4)
68 
69  avio_skip(s->pb, 2);
70  st->codecpar->sample_rate = avio_rb32(s->pb);
71  if (st->codecpar->sample_rate <= 0)
72  return AVERROR_INVALIDDATA;
73  st->start_time = 0;
74  st->duration = avio_rb32(s->pb);
75  avio_skip(s->pb, 40);
76  avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
77 
78  return 0;
79 }
80 
82 {
83  uint32_t type, size;
84  int64_t pos;
85  int ret;
86 
87  if (avio_feof(s->pb))
88  return AVERROR_EOF;
89 
90  pos = avio_tell(s->pb);
91  type = avio_rl32(s->pb);
92  size = avio_rb32(s->pb);
93  if (size > INT_MAX / s->streams[0]->codecpar->channels)
94  return AVERROR_INVALIDDATA;
95 
96  size *= s->streams[0]->codecpar->channels;
97  if ((ret = avio_skip(s->pb, 24)) < 0) // padding
98  return ret;
99 
100  if (type == MKTAG('B','L','C','K')) {
101  ret = av_get_packet(s->pb, pkt, size);
102  pkt->stream_index = 0;
103  pkt->pos = pos;
104  } else {
105  av_log(s, AV_LOG_ERROR, "unknown chunk %x\n", type);
106  avio_skip(s->pb, size);
107  ret = AVERROR_INVALIDDATA;
108  }
109 
110  return ret;
111 }
112 
114  .name = "ast",
115  .long_name = NULL_IF_CONFIG_SMALL("AST (Audio Stream)"),
116  .read_probe = ast_probe,
117  .read_header = ast_read_header,
118  .read_packet = ast_read_packet,
119  .extensions = "ast",
120  .flags = AVFMT_GENERIC_INDEX,
121  .codec_tag = (const AVCodecTag* const []){ff_codec_ast_tags, 0},
122 };
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:631
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
static int ast_read_header(AVFormatContext *s)
Definition: astdec.c:41
enum AVCodecID ff_codec_get_id(const AVCodecTag *tags, unsigned int tag)
Definition: utils.c:2944
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1597
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:4404
static int ast_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: astdec.c:81
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3915
#define AV_CH_LAYOUT_4POINT0
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:287
static AVPacket pkt
#define AV_CH_LAYOUT_STEREO
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:688
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_WB24 unsigned int_TMPL AV_RB16
Definition: bytestream.h:87
static int ast_probe(AVProbeData *p)
Definition: astdec.c:28
Format I/O context.
Definition: avformat.h:1319
void void avpriv_request_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:703
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4042
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_RB32
Definition: bytestream.h:87
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1387
#define AVERROR_EOF
End of file.
Definition: error.h:55
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:260
ptrdiff_t size
Definition: opengl_enc.c:101
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:447
uint64_t channel_layout
Audio only.
Definition: avcodec.h:4017
#define av_log(a,...)
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:672
#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:176
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3911
int depth
Definition: v4l.c:62
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:461
audio channel layout utility functions
Stream structure.
Definition: avformat.h:876
AVIOContext * pb
I/O context.
Definition: avformat.h:1361
GLint GLenum type
Definition: opengl_enc.c:105
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:485
AVInputFormat ff_ast_demuxer
Definition: astdec.c:113
This structure contains the data a format has to probe a file.
Definition: avformat.h:459
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:930
int sample_rate
Audio only.
Definition: avcodec.h:4025
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:471
Main libavformat public API header.
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base...
Definition: avformat.h:923
const AVCodecTag ff_codec_ast_tags[]
Definition: ast.c:25
int channels
Audio only.
Definition: avcodec.h:4021
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:660
AVCodecParameters * codecpar
Definition: avformat.h:1006
int avio_feof(AVIOContext *s)
feof() equivalent for AVIOContext.
Definition: aviobuf.c:311
int stream_index
Definition: avcodec.h:1579
#define MKTAG(a, b, c, d)
Definition: common.h:342
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:87
This structure stores compressed data.
Definition: avcodec.h:1554