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supdec.c
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1 /*
2  * This file is part of FFmpeg.
3  *
4  * FFmpeg is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * FFmpeg is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with FFmpeg; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
19 #include "avformat.h"
20 #include "internal.h"
21 #include "libavutil/intreadwrite.h"
22 
23 #define SUP_PGS_MAGIC 0x5047 /* "PG", big endian */
24 
26 {
28  if (!st)
29  return AVERROR(ENOMEM);
32  avpriv_set_pts_info(st, 32, 1, 90000);
33 
34  return 0;
35 }
36 
38 {
39  int64_t pts, dts, pos;
40  int ret;
41 
42  pos = avio_tell(s->pb);
43 
44  if (avio_rb16(s->pb) != SUP_PGS_MAGIC)
46 
47  pts = avio_rb32(s->pb);
48  dts = avio_rb32(s->pb);
49 
50  if ((ret = av_get_packet(s->pb, pkt, 3)) < 0)
51  return ret;
52 
53  pkt->stream_index = 0;
54  pkt->flags |= AV_PKT_FLAG_KEY;
55  pkt->pos = pos;
56  pkt->pts = pts;
57  // Many files have DTS set to 0 for all packets, so assume 0 means unset.
58  pkt->dts = dts ? dts : AV_NOPTS_VALUE;
59 
60  if (pkt->size >= 3) {
61  // The full packet size is stored as part of the packet.
62  size_t len = AV_RB16(pkt->data + 1);
63 
64  if ((ret = av_append_packet(s->pb, pkt, len)) < 0)
65  return ret;
66  }
67 
68  return 0;
69 }
70 
71 static int sup_probe(AVProbeData *p)
72 {
73  unsigned char *buf = p->buf;
74  size_t buf_size = p->buf_size;
75  int nb_packets;
76 
77  for (nb_packets = 0; nb_packets < 10; nb_packets++) {
78  size_t full_packet_size;
79  if (buf_size < 10 + 3)
80  break;
81  if (AV_RB16(buf) != SUP_PGS_MAGIC)
82  return 0;
83  full_packet_size = AV_RB16(buf + 10 + 1) + 10 + 3;
84  if (buf_size < full_packet_size)
85  break;
86  buf += full_packet_size;
87  buf_size -= full_packet_size;
88  }
89  if (!nb_packets)
90  return 0;
91  if (nb_packets < 2)
92  return AVPROBE_SCORE_RETRY / 2;
93  if (nb_packets < 4)
94  return AVPROBE_SCORE_RETRY;
95  if (nb_packets < 10)
97  return AVPROBE_SCORE_MAX;
98 }
99 
101  .name = "sup",
102  .long_name = NULL_IF_CONFIG_SMALL("raw HDMV Presentation Graphic Stream subtitles"),
103  .extensions = "sup",
104  .mime_type = "application/x-pgs",
105  .read_probe = sup_probe,
106  .read_header = sup_read_header,
107  .read_packet = sup_read_packet,
108  .flags = AVFMT_GENERIC_INDEX,
109 };
#define NULL
Definition: coverity.c:32
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1465
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:4882
AVInputFormat ff_sup_demuxer
Definition: supdec.c:100
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3900
int size
Definition: avcodec.h:1446
#define SUP_PGS_MAGIC
Definition: supdec.c:23
static AVPacket pkt
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:786
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_RB16
Definition: bytestream.h:87
static int sup_probe(AVProbeData *p)
Definition: supdec.c:71
Format I/O context.
Definition: avformat.h:1351
static int sup_read_header(AVFormatContext *s)
Definition: supdec.c:25
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:801
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4455
uint8_t * data
Definition: avcodec.h:1445
#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:310
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
int av_append_packet(AVIOContext *s, AVPacket *pkt, int size)
Read data and append it to the current content of the AVPacket.
Definition: utils.c:320
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: avcodec.h:1477
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3896
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1451
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:451
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:450
#define s(width, name)
Definition: cbs_vp9.c:257
#define AVPROBE_SCORE_RETRY
Definition: avformat.h:455
Stream structure.
Definition: avformat.h:874
AVIOContext * pb
I/O context.
Definition: avformat.h:1393
void * buf
Definition: avisynth_c.h:690
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:470
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:458
This structure contains the data a format has to probe a file.
Definition: avformat.h:448
static int64_t pts
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:460
Main libavformat public API header.
static int sup_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: supdec.c:37
int len
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed...
Definition: avcodec.h:1444
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:647
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1021
int avio_feof(AVIOContext *s)
feof() equivalent for AVIOContext.
Definition: aviobuf.c:358
int stream_index
Definition: avcodec.h:1447
This structure stores compressed data.
Definition: avcodec.h:1422
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1438
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248