FFmpeg  4.4
cdg.c
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1 /*
2  * CD Graphics Demuxer
3  * Copyright (c) 2009 Michael Tison
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 "avformat.h"
23 #include "internal.h"
24 
25 #define CDG_PACKET_SIZE 24
26 #define CDG_COMMAND 0x09
27 #define CDG_MASK 0x3F
28 
30 {
31  AVStream *vst;
32  int ret;
33 
34  vst = avformat_new_stream(s, NULL);
35  if (!vst)
36  return AVERROR(ENOMEM);
37 
40 
41  /// 75 sectors/sec * 4 packets/sector = 300 packets/sec
42  avpriv_set_pts_info(vst, 32, 1, 300);
43 
44  ret = avio_size(s->pb);
45  if (ret < 0) {
46  av_log(s, AV_LOG_WARNING, "Cannot calculate duration as file size cannot be determined\n");
47  } else
48  vst->duration = (ret * (int64_t)vst->time_base.den) / (CDG_PACKET_SIZE * 300);
49 
50  return 0;
51 }
52 
54 {
55  int ret;
56 
57  ret = av_get_packet(s->pb, pkt, CDG_PACKET_SIZE);
58  pkt->stream_index = 0;
59  pkt->dts=
61 
62  if (!pkt->pos || (ret > 5 &&
63  (pkt->data[0] & CDG_MASK) == CDG_COMMAND &&
64  (pkt->data[1] & CDG_MASK) == 1 && !(pkt->data[2+2+1] & 0x0F))) {
66  }
67  return ret;
68 }
69 
71  .name = "cdg",
72  .long_name = NULL_IF_CONFIG_SMALL("CD Graphics"),
73  .read_header = read_header,
74  .read_packet = read_packet,
75  .flags = AVFMT_GENERIC_INDEX,
76  .extensions = "cdg",
77 };
Main libavformat public API header.
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:310
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:463
int64_t avio_size(AVIOContext *s)
Get the filesize.
Definition: aviobuf.c:342
#define s(width, name)
Definition: cbs_vp9.c:257
#define CDG_COMMAND
Definition: cdg.c:26
static int read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: cdg.c:53
AVInputFormat ff_cdg_demuxer
Definition: cdg.c:70
#define CDG_PACKET_SIZE
Definition: cdg.c:25
#define CDG_MASK
Definition: cdg.c:27
static int read_header(AVFormatContext *s)
Definition: cdg.c:29
#define NULL
Definition: coverity.c:32
@ AV_CODEC_ID_CDGRAPHICS
Definition: codec_id.h:181
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:410
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4505
#define AVERROR(e)
Definition: error.h:43
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:200
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
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:4941
common internal API header
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
Format I/O context.
Definition: avformat.h:1232
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:645
This structure stores compressed data.
Definition: packet.h:346
int stream_index
Definition: packet.h:371
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:375
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:362
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed.
Definition: packet.h:368
uint8_t * data
Definition: packet.h:369
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:389
int den
Denominator.
Definition: rational.h:60
Stream structure.
Definition: avformat.h:873
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1038
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:922
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented.
Definition: avformat.h:902
#define av_log(a,...)
AVPacket * pkt
Definition: movenc.c:59