FFmpeg
lvfdec.c
Go to the documentation of this file.
1 /*
2  * LVF 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/intreadwrite.h"
23 #include "avformat.h"
24 #include "riff.h"
25 
26 static int lvf_probe(const AVProbeData *p)
27 {
28  if (AV_RL32(p->buf) != MKTAG('L', 'V', 'F', 'F'))
29  return 0;
30 
31  if (!AV_RL32(p->buf + 16) || AV_RL32(p->buf + 16) > 256)
32  return AVPROBE_SCORE_MAX / 8;
33 
35 }
36 
38 {
39  AVStream *st;
40  int64_t next_offset;
41  unsigned size, nb_streams, id;
42 
43  avio_skip(s->pb, 16);
44  nb_streams = avio_rl32(s->pb);
45  if (!nb_streams)
46  return AVERROR_INVALIDDATA;
47  if (nb_streams > 2) {
48  avpriv_request_sample(s, "%d streams", nb_streams);
49  return AVERROR_PATCHWELCOME;
50  }
51 
52  avio_skip(s->pb, 1012);
53 
54  while (!avio_feof(s->pb)) {
55  id = avio_rl32(s->pb);
56  size = avio_rl32(s->pb);
57  next_offset = avio_tell(s->pb) + size;
58 
59  switch (id) {
60  case MKTAG('0', '0', 'f', 'm'):
61  st = avformat_new_stream(s, 0);
62  if (!st)
63  return AVERROR(ENOMEM);
64 
66  avio_skip(s->pb, 4);
67  st->codecpar->width = avio_rl32(s->pb);
68  st->codecpar->height = avio_rl32(s->pb);
69  avio_skip(s->pb, 4);
70  st->codecpar->codec_tag = avio_rl32(s->pb);
72  st->codecpar->codec_tag);
73  avpriv_set_pts_info(st, 32, 1, 1000);
74  break;
75  case MKTAG('0', '1', 'f', 'm'):
76  st = avformat_new_stream(s, 0);
77  if (!st)
78  return AVERROR(ENOMEM);
79 
81  st->codecpar->codec_tag = avio_rl16(s->pb);
82  st->codecpar->channels = avio_rl16(s->pb);
83  st->codecpar->sample_rate = avio_rl16(s->pb);
84  avio_skip(s->pb, 8);
87  st->codecpar->codec_tag);
88  avpriv_set_pts_info(st, 32, 1, 1000);
89  break;
90  case 0:
91  avio_seek(s->pb, 2048 + 8, SEEK_SET);
92  return 0;
93  default:
94  avpriv_request_sample(s, "id %d", id);
95  return AVERROR_PATCHWELCOME;
96  }
97 
98  avio_seek(s->pb, next_offset, SEEK_SET);
99  }
100 
101  return AVERROR_EOF;
102 }
103 
105 {
106  unsigned size, flags, timestamp, id;
107  int64_t pos;
108  int ret, is_video = 0;
109  int stream_index;
110 
111  pos = avio_tell(s->pb);
112  while (!avio_feof(s->pb)) {
113  id = avio_rl32(s->pb);
114  size = avio_rl32(s->pb);
115 
116  if (size == 0xFFFFFFFFu)
117  return AVERROR_EOF;
118 
119  switch (id) {
120  case MKTAG('0', '0', 'd', 'c'):
121  is_video = 1;
122  case MKTAG('0', '1', 'w', 'b'):
123  if (size < 8)
124  return AVERROR_INVALIDDATA;
125  stream_index = is_video ? 0 : 1;
126  if (stream_index >= s->nb_streams)
127  return AVERROR_INVALIDDATA;
128  timestamp = avio_rl32(s->pb);
129  flags = avio_rl32(s->pb);
130  ret = av_get_packet(s->pb, pkt, size - 8);
131  if (flags & (1 << 12))
132  pkt->flags |= AV_PKT_FLAG_KEY;
133  pkt->stream_index = stream_index;
134  pkt->pts = timestamp;
135  pkt->pos = pos;
136  return ret;
137  default:
138  ret = avio_skip(s->pb, size);
139  }
140 
141  if (ret < 0)
142  return ret;
143  }
144 
145  return AVERROR_EOF;
146 }
147 
149  .name = "lvf",
150  .long_name = NULL_IF_CONFIG_SMALL("LVF"),
151  .read_probe = lvf_probe,
152  .read_header = lvf_read_header,
153  .read_packet = lvf_read_packet,
154  .extensions = "lvf",
155  .flags = AVFMT_GENERIC_INDEX,
156 };
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
enum AVCodecID ff_codec_get_id(const AVCodecTag *tags, unsigned int tag)
Definition: utils.c:3097
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:383
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:4871
#define avpriv_request_sample(...)
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:253
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:341
static AVPacket pkt
Format I/O context.
Definition: avformat.h:1239
static int nb_streams
Definition: ffprobe.c:282
int width
Video only.
Definition: codec_par.h:126
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4453
static int lvf_read_header(AVFormatContext *s)
Definition: lvfdec.c:37
#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:305
ptrdiff_t size
Definition: opengl_enc.c:100
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
static int lvf_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: lvfdec.c:104
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:401
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:754
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:153
unsigned int pos
Definition: spdifenc.c:410
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
const AVCodecTag ff_codec_wav_tags[]
Definition: riff.c:507
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:369
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:628
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1295
const AVCodecTag ff_codec_bmp_tags[]
Definition: riff.c:32
internal header for RIFF based (de)muxers do NOT include this in end user applications ...
AVInputFormat ff_lvf_demuxer
Definition: lvfdec.c:148
#define s(width, name)
Definition: cbs_vp9.c:257
Stream structure.
Definition: avformat.h:880
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:62
AVIOContext * pb
I/O context.
Definition: avformat.h:1281
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:463
static int lvf_probe(const AVProbeData *p)
Definition: lvfdec.c:26
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:451
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
#define flags(name, subs,...)
Definition: cbs_av1.c:560
int sample_rate
Audio only.
Definition: codec_par.h:170
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:453
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:738
Main libavformat public API header.
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: codec_par.h:102
int channels
Audio only.
Definition: codec_par.h:166
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:652
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1045
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:368
uint32_t codec_tag
Additional information about the codec (corresponds to the AVI FOURCC).
Definition: codec_par.h:64
int stream_index
Definition: packet.h:365
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
#define MKTAG(a, b, c, d)
Definition: common.h:405
enum AVCodecID id
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:91
This structure stores compressed data.
Definition: packet.h:340
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:356