FFmpeg: libavformat/vc1test.c Source File

FFmpeg
vc1test.c
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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 
48  return AVPROBE_SCORE_EXTENSION;
49 }
50 
51  static int vc1t_read_header(AVFormatContext *s)
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 
68  st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
69  st->codecpar->codec_id = AV_CODEC_ID_WMV3;
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 
95  static int vc1t_read_packet(AVFormatContext *s,
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_EOF;
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 
120  const FFInputFormat ff_vc1t_demuxer = {
121  .p.name = "vc1test",
122  .p.long_name = NULL_IF_CONFIG_SMALL("VC-1 test bitstream"),
123  .p.extensions = "rcv",
124  .p.flags = AVFMT_GENERIC_INDEX,
125  .read_probe = vc1t_probe,
126  .read_header = vc1t_read_header,
127  .read_packet = vc1t_read_packet,
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
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:51
vc1t_probe
static int vc1t_probe(const AVProbeData *p)
Definition: vc1test.c:36
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
AV_PKT_FLAG_KEY
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:613
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:326
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:777
frames
if it could not because there are no more frames
Definition: filter_design.txt:267
AVFMT_GENERIC_INDEX
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:479
pts
static int64_t pts
Definition: transcode_aac.c:644
AVStream::duration
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:803
pkt
AVPacket * pkt
Definition: movenc.c:60
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:210
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:549
frame_size
int frame_size
Definition: mxfenc.c:2474
AVCodecParameters::width
int width
Video only.
Definition: codec_par.h:134
AVFormatContext
Format I/O context.
Definition: avformat.h:1264
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:767
NULL
#define NULL
Definition: coverity.c:32
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:451
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:461
VC1_EXTRADATA_SIZE
#define VC1_EXTRADATA_SIZE
Definition: vc1test.c:34
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:733
AVIOContext
Bytestream IO Context.
Definition: avio.h:160
AVPacket::size
int size
Definition: packet.h:559
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
size
int size
Definition: twinvq_data.h:10344
ff_vc1t_demuxer
const FFInputFormat ff_vc1t_demuxer
Definition: vc1test.c:120
vc1t_read_header
static int vc1t_read_header(AVFormatContext *s)
Definition: vc1test.c:51
FFInputFormat::p
AVInputFormat p
The public AVInputFormat.
Definition: demux.h:51
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:606
AVPacket::flags
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:564
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:551
avio_rl24
unsigned int avio_rl24(AVIOContext *s)
Definition: aviobuf.c:725
AVCodecParameters::height
int height
Definition: codec_par.h:135
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:98
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:744
avformat.h
AV_RL32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:92
Windows::Graphics::DirectX::Direct3D11::p
IDirect3DDxgiInterfaceAccess _COM_Outptr_ void ** p
Definition: vsrc_gfxcapture_winrt.hpp:53
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:321
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:200
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:535
AVPacket::pos
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:578
vc1t_read_packet
static int vc1t_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: vc1test.c:95
FFInputFormat
Definition: demux.h:47
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:349
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