FFmpeg: libavformat/supdec.c Source File

FFmpeg
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 
25  static int sup_read_header(AVFormatContext *s)
26 {
27  AVStream *st = avformat_new_stream(s, NULL);
28  if (!st)
29  return AVERROR(ENOMEM);
30  st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
31  st->codecpar->codec_id = AV_CODEC_ID_HDMV_PGS_SUBTITLE;
32  avpriv_set_pts_info(st, 32, 1, 90000);
33 
34  return 0;
35 }
36 
37  static int sup_read_packet(AVFormatContext *s, AVPacket *pkt)
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)
45  return avio_feof(s->pb) ? AVERROR_EOF : AVERROR_INVALIDDATA;
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)
96  return AVPROBE_SCORE_EXTENSION;
97  return AVPROBE_SCORE_MAX;
98 }
99 
100  AVInputFormat ff_sup_demuxer = {
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 };
NULL
#define NULL
Definition: coverity.c:32
s
const char * s
Definition: avisynth_c.h:768
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
AVPacket::pos
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1450
avpriv_set_pts_info
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:4820
ff_sup_demuxer
AVInputFormat ff_sup_demuxer
Definition: supdec.c:100
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3884
AVPacket::size
int size
Definition: avcodec.h:1431
SUP_PGS_MAGIC
#define SUP_PGS_MAGIC
Definition: supdec.c:23
pkt
static AVPacket pkt
Definition: demuxing_decoding.c:54
avio_rb16
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:786
AV_RB16
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
sup_probe
static int sup_probe(AVProbeData *p)
Definition: supdec.c:71
AVFormatContext
Format I/O context.
Definition: avformat.h:1342
sup_read_header
static int sup_read_header(AVFormatContext *s)
Definition: supdec.c:25
avio_rb32
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:801
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4450
AVPacket::data
uint8_t * data
Definition: avcodec.h:1430
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:55
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:310
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
av_append_packet
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
AV_PKT_FLAG_KEY
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: avcodec.h:1462
AVERROR
#define AVERROR(e)
Definition: error.h:43
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:186
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3880
AVPacket::flags
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1436
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:451
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:450
AVPROBE_SCORE_RETRY
#define AVPROBE_SCORE_RETRY
Definition: avformat.h:455
AVStream
Stream structure.
Definition: avformat.h:873
AVFormatContext::pb
AVIOContext * pb
I/O context.
Definition: avformat.h:1384
buf
void * buf
Definition: avisynth_c.h:690
AVFMT_GENERIC_INDEX
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:470
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:458
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:448
pts
static int64_t pts
Definition: transcode_aac.c:647
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:460
avformat.h
Main libavformat public API header.
sup_read_packet
static int sup_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: supdec.c:37
len
int len
Definition: vorbis_enc_data.h:452
AVPacket::dts
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed...
Definition: avcodec.h:1429
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:647
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1020
avio_feof
int avio_feof(AVIOContext *s)
feof() equivalent for AVIOContext.
Definition: aviobuf.c:358
AVPacket::stream_index
int stream_index
Definition: avcodec.h:1432
AVPacket
This structure stores compressed data.
Definition: avcodec.h:1407
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1423
AV_NOPTS_VALUE
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248

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