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 
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(const 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
static int sup_probe(const AVProbeData *p)
Definition: supdec.c:71
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1500
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:4896
AVInputFormat ff_sup_demuxer
Definition: supdec.c:100
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3960
int size
Definition: avcodec.h:1481
#define SUP_PGS_MAGIC
Definition: supdec.c:23
static AVPacket pkt
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:788
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
Format I/O context.
Definition: avformat.h:1358
static int sup_read_header(AVFormatContext *s)
Definition: supdec.c:25
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:803
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4469
uint8_t * data
Definition: avcodec.h:1480
#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:1512
#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:3956
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1486
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
#define s(width, name)
Definition: cbs_vp9.c:257
#define AVPROBE_SCORE_RETRY
Definition: avformat.h:453
Stream structure.
Definition: avformat.h:881
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
void * buf
Definition: avisynth_c.h:766
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:468
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:456
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
static int64_t pts
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
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:1479
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:654
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:361
int stream_index
Definition: avcodec.h:1482
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
This structure stores compressed data.
Definition: avcodec.h:1457
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1473
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248