FFmpeg
dcstr.c
Go to the documentation of this file.
1 /*
2  * DC STR demuxer
3  * Copyright (c) 2015 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 "avformat.h"
23 #include "internal.h"
24 
25 static int dcstr_probe(const AVProbeData *p)
26 {
27  if (p->buf_size < 224 || memcmp(p->buf + 213, "Sega Stream", 11))
28  return 0;
29 
30  return AVPROBE_SCORE_MAX;
31 }
32 
34 {
35  unsigned codec, align;
36  int mult;
37  AVStream *st;
38 
39  st = avformat_new_stream(s, NULL);
40  if (!st)
41  return AVERROR(ENOMEM);
42 
44  st->codecpar->channels = avio_rl32(s->pb);
45  st->codecpar->sample_rate = avio_rl32(s->pb);
46  if (st->codecpar->sample_rate <= 0)
47  return AVERROR_INVALIDDATA;
48  codec = avio_rl32(s->pb);
49  align = avio_rl32(s->pb);
50  avio_skip(s->pb, 4);
51  st->duration = avio_rl32(s->pb);
52  mult = avio_rl32(s->pb);
53  if (st->codecpar->channels <= 0 || mult <= 0 || mult > INT_MAX / st->codecpar->channels) {
54  av_log(s, AV_LOG_ERROR, "invalid number of channels %d x %d\n", st->codecpar->channels, mult);
55  return AVERROR_INVALIDDATA;
56  }
57  st->codecpar->channels *= mult;
58  if (!align || align > INT_MAX / st->codecpar->channels)
59  return AVERROR_INVALIDDATA;
60  st->codecpar->block_align = align * st->codecpar->channels;
61 
62  switch (codec) {
63  case 4: st->codecpar->codec_id = AV_CODEC_ID_ADPCM_AICA; break;
64  case 16: st->codecpar->codec_id = AV_CODEC_ID_PCM_S16LE_PLANAR; break;
65  default: avpriv_request_sample(s, "codec %X", codec);
66  return AVERROR_PATCHWELCOME;
67  }
68 
69  avio_skip(s->pb, 0x800 - avio_tell(s->pb));
70  avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
71 
72  return 0;
73 }
74 
76 {
77  AVCodecParameters *par = s->streams[0]->codecpar;
78  return av_get_packet(s->pb, pkt, par->block_align);
79 }
80 
82  .name = "dcstr",
83  .long_name = NULL_IF_CONFIG_SMALL("Sega DC STR"),
84  .read_probe = dcstr_probe,
85  .read_header = dcstr_read_header,
86  .read_packet = dcstr_read_packet,
87  .extensions = "str",
89 };
AVFMT_NO_BYTE_SEEK
#define AVFMT_NO_BYTE_SEEK
Format does not allow seeking by bytes.
Definition: avformat.h:476
AVERROR
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
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:760
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
AVCodecParameters
This struct describes the properties of an encoded stream.
Definition: codec_par.h:52
AV_CODEC_ID_ADPCM_AICA
@ AV_CODEC_ID_ADPCM_AICA
Definition: codec_id.h:391
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:450
AVFMT_NOBINSEARCH
#define AVFMT_NOBINSEARCH
Format does not allow to fall back on binary search via read_timestamp.
Definition: avformat.h:474
AV_CODEC_ID_PCM_S16LE_PLANAR
@ AV_CODEC_ID_PCM_S16LE_PLANAR
Definition: codec_id.h:332
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:459
AVCodecParameters::channels
int channels
Audio only.
Definition: codec_par.h:166
dcstr_probe
static int dcstr_probe(const AVProbeData *p)
Definition: dcstr.c:25
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:504
AVFMT_GENERIC_INDEX
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:469
AVStream::duration
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:978
mult
static int16_t mult(Float11 *f1, Float11 *f2)
Definition: g726.c:56
pkt
AVPacket * pkt
Definition: movenc.c:59
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
AVInputFormat
Definition: avformat.h:643
dcstr_read_packet
static int dcstr_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: dcstr.c:75
s
#define s(width, name)
Definition: cbs_vp9.c:257
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:648
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:449
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVFormatContext
Format I/O context.
Definition: avformat.h:1193
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1088
NULL
#define NULL
Definition: coverity.c:32
AVERROR_PATCHWELCOME
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:64
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:447
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: codec_par.h:170
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:759
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:117
ff_dcstr_demuxer
const AVInputFormat ff_dcstr_demuxer
Definition: dcstr.c:81
AVCodecParameters::block_align
int block_align
Audio only.
Definition: codec_par.h:177
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:197
AVStream
Stream structure.
Definition: avformat.h:928
avformat.h
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *st, 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:1186
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:347
avpriv_request_sample
#define avpriv_request_sample(...)
Definition: tableprint_vlc.h:37
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
AVPacket
This structure stores compressed data.
Definition: packet.h:350
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
dcstr_read_header
static int dcstr_read_header(AVFormatContext *s)
Definition: dcstr.c:33