FFmpeg: libavformat/astdec.c Source File

FFmpeg
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 
22 #include "libavutil/channel_layout.h"
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 
41  static int ast_read_header(AVFormatContext *s)
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);
51  st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
52  st->codecpar->codec_id = ff_codec_get_id(ff_codec_ast_tags, avio_rb16(s->pb));
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)
65  st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
66  else if (st->codecpar->channels == 4)
67  st->codecpar->channel_layout = AV_CH_LAYOUT_4POINT0;
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 
81  static int ast_read_packet(AVFormatContext *s, AVPacket *pkt)
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 (!s->streams[0]->codecpar->channels || 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 %"PRIx32"\n", type);
106  avio_skip(s->pb, size);
107  ret = AVERROR_INVALIDDATA;
108  }
109 
110  return ret;
111 }
112 
113  AVInputFormat ff_ast_demuxer = {
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 };
NULL
#define NULL
Definition: coverity.c:32
s
const char * s
Definition: avisynth_c.h:768
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
ast_read_header
static int ast_read_header(AVFormatContext *s)
Definition: astdec.c:41
ff_codec_get_id
enum AVCodecID ff_codec_get_id(const AVCodecTag *tags, unsigned int tag)
Definition: utils.c:3117
AVPacket::pos
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1450
avpriv_set_pts_info
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:4820
ast_read_packet
static int ast_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: astdec.c:81
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3884
AV_CH_LAYOUT_4POINT0
#define AV_CH_LAYOUT_4POINT0
Definition: channel_layout.h:91
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:331
pkt
static AVPacket pkt
Definition: demuxing_decoding.c:54
AV_CH_LAYOUT_STEREO
#define AV_CH_LAYOUT_STEREO
Definition: channel_layout.h:86
avio_rb16
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:786
AV_RB16
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
ast_probe
static int ast_probe(AVProbeData *p)
Definition: astdec.c:28
AVFormatContext
Format I/O context.
Definition: avformat.h:1342
avpriv_request_sample
void void avpriv_request_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
avio_rb32
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:801
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4450
AV_RB32
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
AVFormatContext::streams
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1410
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:55
av_get_packet
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:310
size
ptrdiff_t size
Definition: opengl_enc.c:101
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
AVCodecParameters::channel_layout
uint64_t channel_layout
Audio only.
Definition: avcodec.h:3986
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:770
AVERROR
#define AVERROR(e)
Definition: error.h:43
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3880
AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:450
channel_layout.h
audio channel layout utility functions
AVStream
Stream structure.
Definition: avformat.h:873
AVFormatContext::pb
AVIOContext * pb
I/O context.
Definition: avformat.h:1384
type
GLint GLenum type
Definition: opengl_enc.c:105
AVFMT_GENERIC_INDEX
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:470
ff_ast_demuxer
AVInputFormat ff_ast_demuxer
Definition: astdec.c:113
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:448
AVStream::duration
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:922
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: avcodec.h:3994
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:460
avformat.h
Main libavformat public API header.
AVStream::start_time
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base...
Definition: avformat.h:912
ff_codec_ast_tags
const AVCodecTag ff_codec_ast_tags[]
Definition: ast.c:25
AVCodecParameters::channels
int channels
Audio only.
Definition: avcodec.h:3990
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:647
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1020
avio_feof
int avio_feof(AVIOContext *s)
feof() equivalent for AVIOContext.
Definition: aviobuf.c:358
AVPacket::stream_index
int stream_index
Definition: avcodec.h:1432
MKTAG
#define MKTAG(a, b, c, d)
Definition: common.h:366
AV_RL32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:87
AVPacket
This structure stores compressed data.
Definition: avcodec.h:1407
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