FFmpeg
lvfdec.c
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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 "demux.h"
25 #include "riff.h"
26 
27 static int lvf_probe(const AVProbeData *p)
28 {
29  if (AV_RL32(p->buf) != MKTAG('L', 'V', 'F', 'F'))
30  return 0;
31 
32  if (!AV_RL32(p->buf + 16) || AV_RL32(p->buf + 16) > 256)
33  return AVPROBE_SCORE_MAX / 8;
34 
36 }
37 
39 {
40  AVStream *st;
41  int64_t next_offset;
42  unsigned size, nb_streams, id;
43 
44  avio_skip(s->pb, 16);
45  nb_streams = avio_rl32(s->pb);
46  if (!nb_streams)
47  return AVERROR_INVALIDDATA;
48  if (nb_streams > 2) {
49  avpriv_request_sample(s, "%d streams", nb_streams);
50  return AVERROR_PATCHWELCOME;
51  }
52 
53  avio_skip(s->pb, 1012);
54 
55  while (!avio_feof(s->pb)) {
56  id = avio_rl32(s->pb);
57  size = avio_rl32(s->pb);
58  next_offset = avio_tell(s->pb) + size;
59 
60  switch (id) {
61  case MKTAG('0', '0', 'f', 'm'):
62  st = avformat_new_stream(s, 0);
63  if (!st)
64  return AVERROR(ENOMEM);
65 
67  avio_skip(s->pb, 4);
68  st->codecpar->width = avio_rl32(s->pb);
69  st->codecpar->height = avio_rl32(s->pb);
70  avio_skip(s->pb, 4);
71  st->codecpar->codec_tag = avio_rl32(s->pb);
73  st->codecpar->codec_tag);
74  avpriv_set_pts_info(st, 32, 1, 1000);
75  break;
76  case MKTAG('0', '1', 'f', 'm'):
77  st = avformat_new_stream(s, 0);
78  if (!st)
79  return AVERROR(ENOMEM);
80 
82  st->codecpar->codec_tag = avio_rl16(s->pb);
84  st->codecpar->sample_rate = avio_rl16(s->pb);
85  avio_skip(s->pb, 8);
88  st->codecpar->codec_tag);
89  avpriv_set_pts_info(st, 32, 1, 1000);
90  break;
91  case 0:
92  avio_seek(s->pb, 2048 + 8, SEEK_SET);
93  return 0;
94  default:
95  avpriv_request_sample(s, "id %d", id);
96  return AVERROR_PATCHWELCOME;
97  }
98 
99  avio_seek(s->pb, next_offset, SEEK_SET);
100  }
101 
102  return AVERROR_EOF;
103 }
104 
106 {
107  unsigned size, flags, timestamp, id;
108  int64_t pos;
109  int ret, is_video = 0;
110  int stream_index;
111 
112  pos = avio_tell(s->pb);
113  while (!avio_feof(s->pb)) {
114  id = avio_rl32(s->pb);
115  size = avio_rl32(s->pb);
116 
117  if (size == 0xFFFFFFFFu)
118  return AVERROR_EOF;
119 
120  switch (id) {
121  case MKTAG('0', '0', 'd', 'c'):
122  is_video = 1;
123  case MKTAG('0', '1', 'w', 'b'):
124  if (size < 8)
125  return AVERROR_INVALIDDATA;
126  stream_index = is_video ? 0 : 1;
127  if (stream_index >= s->nb_streams)
128  return AVERROR_INVALIDDATA;
129  timestamp = avio_rl32(s->pb);
130  flags = avio_rl32(s->pb);
131  ret = av_get_packet(s->pb, pkt, size - 8);
132  if (flags & (1 << 12))
134  pkt->stream_index = stream_index;
135  pkt->pts = timestamp;
136  pkt->pos = pos;
137  return ret;
138  default:
139  ret = avio_skip(s->pb, size);
140  }
141 
142  if (ret < 0)
143  return ret;
144  }
145 
146  return AVERROR_EOF;
147 }
148 
150  .p.name = "lvf",
151  .p.long_name = NULL_IF_CONFIG_SMALL("LVF"),
152  .p.extensions = "lvf",
153  .p.flags = AVFMT_GENERIC_INDEX,
154  .read_probe = lvf_probe,
155  .read_header = lvf_read_header,
156  .read_packet = lvf_read_packet,
157 };
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
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:51
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const struct AVCodec *c)
Add a new stream to a media file.
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
ff_codec_wav_tags
const AVCodecTag ff_codec_wav_tags[]
Definition: riff.c:519
AVCodecParameters::codec_tag
uint32_t codec_tag
Additional information about the codec (corresponds to the AVI FOURCC).
Definition: codec_par.h:59
AVChannelLayout::nb_channels
int nb_channels
Number of channels in this layout.
Definition: channel_layout.h:313
AV_PKT_FLAG_KEY
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:579
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:463
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: avformat.c:853
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:494
AVFMT_GENERIC_INDEX
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:480
avio_rl16
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:714
pkt
AVPacket * pkt
Definition: movenc.c:60
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:198
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:553
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:453
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVCodecParameters::width
int width
Video only.
Definition: codec_par.h:134
nb_streams
static int nb_streams
Definition: ffprobe.c:384
AVFormatContext
Format I/O context.
Definition: avformat.h:1255
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:766
AVERROR_PATCHWELCOME
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:64
ff_lvf_demuxer
const FFInputFormat ff_lvf_demuxer
Definition: lvfdec.c:149
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:451
lvf_read_packet
static int lvf_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: lvfdec.c:105
AVCodecParameters::ch_layout
AVChannelLayout ch_layout
Audio only.
Definition: codec_par.h:180
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:461
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: codec_par.h:184
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:730
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:94
ff_codec_get_id
enum AVCodecID ff_codec_get_id(const AVCodecTag *tags, unsigned int tag)
Definition: utils.c:133
size
int size
Definition: twinvq_data.h:10344
FFInputFormat::p
AVInputFormat p
The public AVInputFormat.
Definition: demux.h:41
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:603
AVPacket::flags
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:530
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:517
AVCodecParameters::height
int height
Definition: codec_par.h:135
demux.h
lvf_read_header
static int lvf_read_header(AVFormatContext *s)
Definition: lvfdec.c:38
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:91
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:743
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:231
pos
unsigned int pos
Definition: spdifenc.c:414
avformat.h
id
enum AVCodecID id
Definition: dts2pts.c:365
AV_RL32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:92
ff_codec_bmp_tags
const AVCodecTag ff_codec_bmp_tags[]
Definition: riff.c:36
AVPacket::stream_index
int stream_index
Definition: packet.h:526
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:318
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AVCodecParameters::bits_per_coded_sample
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: codec_par.h:110
avpriv_request_sample
#define avpriv_request_sample(...)
Definition: tableprint_vlc.h:36
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:55
AVPacket
This structure stores compressed data.
Definition: packet.h:501
riff.h
AVPacket::pos
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:544
FFInputFormat
Definition: demux.h:37
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:474
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
MKTAG
#define MKTAG(a, b, c, d)
Definition: macros.h:55
lvf_probe
static int lvf_probe(const AVProbeData *p)
Definition: lvfdec.c:27
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:346