FFmpeg
mods.c
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1 /*
2  * MODS demuxer
3  * Copyright (c) 2015-2016 Florian Nouwt
4  * Copyright (c) 2017 Adib Surani
5  * Copyright (c) 2020 Paul B Mahol
6  *
7  * This file is part of FFmpeg.
8  *
9  * FFmpeg is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * FFmpeg is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
24 #include "libavutil/intreadwrite.h"
25 
26 #include "avformat.h"
27 #include "internal.h"
28 
29 static int mods_probe(const AVProbeData *p)
30 {
31  if (memcmp(p->buf, "MODSN3\x0a\x00", 8))
32  return 0;
33  if (AV_RB32(p->buf + 8) == 0)
34  return 0;
35  if (AV_RB32(p->buf + 12) == 0)
36  return 0;
37  if (AV_RB32(p->buf + 16) == 0)
38  return 0;
39  return AVPROBE_SCORE_MAX;
40 }
41 
43 {
44  AVIOContext *pb = s->pb;
45  AVRational fps;
46  int64_t pos;
47 
49  if (!st)
50  return AVERROR(ENOMEM);
51 
52  avio_skip(pb, 8);
53 
54  st->nb_frames = avio_rl32(pb);
57  st->codecpar->width = avio_rl32(pb);
58  st->codecpar->height = avio_rl32(pb);
59 
60  fps.num = avio_rl32(pb);
61  fps.den = 0x1000000;
62  avpriv_set_pts_info(st, 64, fps.den, fps.num);
63 
64  avio_skip(pb, 16);
65 
66  pos = avio_rl32(pb) + 4;
67  avio_seek(pb, pos, SEEK_SET);
68  pos = avio_rl32(pb);
69  avio_seek(pb, pos, SEEK_SET);
70 
71  return 0;
72 }
73 
75 {
76  AVIOContext *pb = s->pb;
77  unsigned size;
78  int64_t pos;
79  int ret;
80 
81  if (avio_feof(pb))
82  return AVERROR_EOF;
83 
84  pos = avio_tell(pb);
85  size = avio_rl32(pb) >> 14;
86  ret = av_get_packet(pb, pkt, size);
87  pkt->pos = pos;
88  pkt->stream_index = 0;
90 
91  return ret;
92 }
93 
95  .name = "mods",
96  .long_name = NULL_IF_CONFIG_SMALL("MobiClip MODS"),
97  .read_probe = mods_probe,
98  .read_header = mods_read_header,
99  .read_packet = mods_read_packet,
100  .extensions = "mods",
101  .flags = AVFMT_GENERIC_INDEX,
102 };
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:4347
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
AV_CODEC_ID_MOBICLIP
@ AV_CODEC_ID_MOBICLIP
Definition: codec_id.h:303
mods_read_header
static int mods_read_header(AVFormatContext *s)
Definition: mods.c:42
AV_PKT_FLAG_KEY
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:425
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:486
AVFMT_GENERIC_INDEX
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:468
AVRational::num
int num
Numerator.
Definition: rational.h:59
pkt
AVPacket * pkt
Definition: movenc.c:59
AVInputFormat
Definition: avformat.h:626
intreadwrite.h
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:631
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
AVCodecParameters::width
int width
Video only.
Definition: codec_par.h:126
AVFormatContext
Format I/O context.
Definition: avformat.h:1107
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:994
NULL
#define NULL
Definition: coverity.c:32
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
AVStream::nb_frames
int64_t nb_frames
number of frames in this stream if known or 0
Definition: avformat.h:892
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:742
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
mods_probe
static int mods_probe(const AVProbeData *p)
Definition: mods.c:29
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
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:4771
size
int size
Definition: twinvq_data.h:10344
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:96
AVPacket::flags
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:379
mods_read_packet
static int mods_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: mods.c:74
AVCodecParameters::height
int height
Definition: codec_par.h:127
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:257
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:847
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:246
pos
unsigned int pos
Definition: spdifenc.c:412
avformat.h
AVRational::den
int den
Denominator.
Definition: rational.h:60
ff_mods_demuxer
const AVInputFormat ff_mods_demuxer
Definition: mods.c:94
AVPacket::stream_index
int stream_index
Definition: packet.h:375
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:333
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
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
AVPacket::pos
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:393
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:360