FFmpeg
vc1test.c
Go to the documentation of this file.
1 /*
2  * VC1 Test Bitstreams Format Demuxer
3  * Copyright (c) 2006, 2008 Konstantin Shishkov
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 /**
23  * @file
24  * VC1 test bitstream file demuxer
25  * by Konstantin Shishkov
26  * Format specified in SMPTE standard 421 Annex L
27  */
28 
29 #include "libavutil/intreadwrite.h"
30 #include "avformat.h"
31 #include "demux.h"
32 #include "internal.h"
33 
34 #define VC1_EXTRADATA_SIZE 4
35 
36 static int vc1t_probe(const AVProbeData *p)
37 {
38  uint32_t size;
39 
40  if (p->buf_size < 24)
41  return 0;
42 
43  size = AV_RL32(&p->buf[4]);
44  if (p->buf[3] != 0xC5 || size < 4 || size > p->buf_size - 20 ||
45  AV_RL32(&p->buf[size+16]) != 0xC)
46  return 0;
47 
49 }
50 
52 {
53  AVIOContext *pb = s->pb;
54  AVStream *st;
55  int frames, ret;
56  uint32_t fps;
57  uint32_t size;
58 
59  frames = avio_rl24(pb);
60  if (avio_r8(pb) != 0xC5 || ((size = avio_rl32(pb)) < 4))
61  return AVERROR_INVALIDDATA;
62 
63  /* init video codec */
64  st = avformat_new_stream(s, NULL);
65  if (!st)
66  return AVERROR(ENOMEM);
67 
70 
71  if ((ret = ff_get_extradata(s, st->codecpar, pb, VC1_EXTRADATA_SIZE)) < 0)
72  return ret;
73 
74  avio_skip(pb, size - 4);
75  st->codecpar->height = avio_rl32(pb);
76  st->codecpar->width = avio_rl32(pb);
77  if(avio_rl32(pb) != 0xC)
78  return AVERROR_INVALIDDATA;
79  avio_skip(pb, 8);
80  fps = avio_rl32(pb);
81  if(fps == 0xFFFFFFFF)
82  avpriv_set_pts_info(st, 32, 1, 1000);
83  else{
84  if (!fps) {
85  av_log(s, AV_LOG_ERROR, "Zero FPS specified, defaulting to 1 FPS\n");
86  fps = 1;
87  }
88  avpriv_set_pts_info(st, 24, 1, fps);
89  st->duration = frames;
90  }
91 
92  return 0;
93 }
94 
96  AVPacket *pkt)
97 {
98  AVIOContext *pb = s->pb;
99  int frame_size;
100  int keyframe = 0;
101  uint32_t pts;
102 
103  if(avio_feof(pb))
104  return AVERROR(EIO);
105 
106  frame_size = avio_rl24(pb);
107  if(avio_r8(pb) & 0x80)
108  keyframe = 1;
109  pts = avio_rl32(pb);
110  if(av_get_packet(pb, pkt, frame_size) < 0)
111  return AVERROR(EIO);
112  if(s->streams[0]->time_base.den == 1000)
113  pkt->pts = pts;
114  pkt->flags |= keyframe ? AV_PKT_FLAG_KEY : 0;
115  pkt->pos -= 8;
116 
117  return pkt->size;
118 }
119 
121  .name = "vc1test",
122  .long_name = NULL_IF_CONFIG_SMALL("VC-1 test bitstream"),
123  .read_probe = vc1t_probe,
124  .read_header = vc1t_read_header,
125  .read_packet = vc1t_read_packet,
126  .extensions = "rcv",
127  .flags = AVFMT_GENERIC_INDEX,
128 };
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: options.c:237
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:57
vc1t_probe
static int vc1t_probe(const AVProbeData *p)
Definition: vc1test.c:36
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:456
AV_PKT_FLAG_KEY
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:429
ff_vc1t_demuxer
const AVInputFormat ff_vc1t_demuxer
Definition: vc1test.c:120
ff_get_extradata
int ff_get_extradata(void *logctx, AVCodecParameters *par, AVIOContext *pb, int size)
Allocate extradata with additional AV_INPUT_BUFFER_PADDING_SIZE at end which is always set to 0 and f...
Definition: demux_utils.c:355
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:763
frames
if it could not because there are no more frames
Definition: filter_design.txt:266
AVFMT_GENERIC_INDEX
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:482
pts
static int64_t pts
Definition: transcode_aac.c:654
AVStream::duration
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:998
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:656
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:256
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:661
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:455
frame_size
int frame_size
Definition: mxfenc.c:2202
AVCodecParameters::width
int width
Video only.
Definition: codec_par.h:127
AVFormatContext
Format I/O context.
Definition: avformat.h:1216
AV_CODEC_ID_WMV3
@ AV_CODEC_ID_WMV3
Definition: codec_id.h:123
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1108
NULL
#define NULL
Definition: coverity.c:32
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:453
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:463
VC1_EXTRADATA_SIZE
#define VC1_EXTRADATA_SIZE
Definition: vc1test.c:34
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:759
AVIOContext
Bytestream IO Context.
Definition: avio.h:162
AVPacket::size
int size
Definition: packet.h:375
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:115
size
int size
Definition: twinvq_data.h:10344
vc1t_read_header
static int vc1t_read_header(AVFormatContext *s)
Definition: vc1test.c:51
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:632
AVPacket::flags
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:380
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:367
avio_rl24
unsigned int avio_rl24(AVIOContext *s)
Definition: aviobuf.c:751
AVCodecParameters::height
int height
Definition: codec_par.h:128
demux.h
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:102
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:948
avformat.h
AV_RL32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:92
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:347
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:61
AVPacket
This structure stores compressed data.
Definition: packet.h:351
AVPacket::pos
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:394
vc1t_read_packet
static int vc1t_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: vc1test.c:95
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:375