FFmpeg
samidec.c
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1 /*
2  * Copyright (c) 2012 Clément Bœsch
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * SAMI subtitle demuxer
24  * @see http://msdn.microsoft.com/en-us/library/ms971327.aspx
25  */
26 
27 #include "avformat.h"
28 #include "internal.h"
29 #include "subtitles.h"
30 #include "libavcodec/internal.h"
31 #include "libavutil/avstring.h"
32 #include "libavutil/bprint.h"
33 #include "libavutil/intreadwrite.h"
34 
35 typedef struct {
37 } SAMIContext;
38 
39 static int sami_probe(const AVProbeData *p)
40 {
41  char buf[6];
42  FFTextReader tr;
43  ff_text_init_buf(&tr, p->buf, p->buf_size);
44  ff_text_read(&tr, buf, sizeof(buf));
45 
46  return !strncmp(buf, "<SAMI>", 6) ? AVPROBE_SCORE_MAX : 0;
47 }
48 
50 {
51  SAMIContext *sami = s->priv_data;
53  AVBPrint buf, hdr_buf;
54  char c = 0;
55  int res = 0, got_first_sync_point = 0;
56  FFTextReader tr;
57  ff_text_init_avio(s, &tr, s->pb);
58 
59  if (!st)
60  return AVERROR(ENOMEM);
61  avpriv_set_pts_info(st, 64, 1, 1000);
64 
67 
68  while (!ff_text_eof(&tr)) {
69  AVPacket *sub;
70  const int64_t pos = ff_text_pos(&tr) - (c != 0);
71  int is_sync, is_body, n = ff_smil_extract_next_text_chunk(&tr, &buf, &c);
72 
73  if (n == 0)
74  break;
75 
76  is_body = !av_strncasecmp(buf.str, "</BODY", 6);
77  if (is_body) {
78  av_bprint_clear(&buf);
79  break;
80  }
81 
82  is_sync = !av_strncasecmp(buf.str, "<SYNC", 5);
83  if (is_sync)
84  got_first_sync_point = 1;
85 
86  if (!got_first_sync_point) {
87  av_bprintf(&hdr_buf, "%s", buf.str);
88  } else {
89  sub = ff_subtitles_queue_insert(&sami->q, buf.str, buf.len, !is_sync);
90  if (!sub) {
91  res = AVERROR(ENOMEM);
92  goto end;
93  }
94  if (is_sync) {
95  const char *p = ff_smil_get_attr_ptr(buf.str, "Start");
96  sub->pos = pos;
97  sub->pts = p ? strtol(p, NULL, 10) : 0;
98  sub->duration = -1;
99  }
100  }
101  av_bprint_clear(&buf);
102  }
103 
104  res = ff_bprint_to_codecpar_extradata(st->codecpar, &hdr_buf);
105  if (res < 0)
106  goto end;
107 
108  ff_subtitles_queue_finalize(s, &sami->q);
109 
110 end:
111  av_bprint_finalize(&buf, NULL);
112  return res;
113 }
114 
116 {
117  SAMIContext *sami = s->priv_data;
118  return ff_subtitles_queue_read_packet(&sami->q, pkt);
119 }
120 
121 static int sami_read_seek(AVFormatContext *s, int stream_index,
122  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
123 {
124  SAMIContext *sami = s->priv_data;
125  return ff_subtitles_queue_seek(&sami->q, s, stream_index,
126  min_ts, ts, max_ts, flags);
127 }
128 
130 {
131  SAMIContext *sami = s->priv_data;
132  ff_subtitles_queue_clean(&sami->q);
133  return 0;
134 }
135 
137  .name = "sami",
138  .long_name = NULL_IF_CONFIG_SMALL("SAMI subtitle format"),
139  .priv_data_size = sizeof(SAMIContext),
143  .read_seek2 = sami_read_seek,
145  .extensions = "smi,sami",
146 };
#define NULL
Definition: coverity.c:32
void av_bprintf(AVBPrint *buf, const char *fmt,...)
Definition: bprint.c:94
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1497
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
static int sami_read_seek(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Definition: samidec.c:121
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3953
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:297
int av_strncasecmp(const char *a, const char *b, size_t n)
Locale-independent case-insensitive compare.
Definition: avstring.c:223
static AVPacket pkt
int av_bprint_finalize(AVBPrint *buf, char **ret_str)
Finalize a print buffer.
Definition: bprint.c:235
Format I/O context.
Definition: avformat.h:1358
const char * ff_smil_get_attr_ptr(const char *s, const char *attr)
SMIL helper to point on the value of an attribute in the given tag.
Definition: subtitles.c:330
int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)
Generic read_packet() callback for subtitles demuxers using this queue system.
Definition: subtitles.c:208
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: avcodec.h:1495
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
AVInputFormat ff_sami_demuxer
Definition: samidec.c:136
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4455
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:145
#define AV_BPRINT_SIZE_UNLIMITED
int ff_text_eof(FFTextReader *r)
Return non-zero if EOF was reached.
Definition: subtitles.c:92
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
Definition: bprint.c:69
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3949
void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb)
Initialize the FFTextReader from the given AVIOContext.
Definition: subtitles.c:27
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
int64_t ff_text_pos(FFTextReader *r)
Return the byte position of the next byte returned by ff_text_r8().
Definition: subtitles.c:60
static int sami_probe(const AVProbeData *p)
Definition: samidec.c:39
#define s(width, name)
Definition: cbs_vp9.c:257
int n
Definition: avisynth_c.h:760
void ff_text_read(FFTextReader *r, char *buf, size_t size)
Read the given number of bytes (in UTF-8).
Definition: subtitles.c:86
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:530
Stream structure.
Definition: avformat.h:881
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
int ff_subtitles_queue_seek(FFDemuxSubtitlesQueue *q, AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Update current_sub_idx to emulate a seek.
Definition: subtitles.c:245
int ff_smil_extract_next_text_chunk(FFTextReader *tr, AVBPrint *buf, char *c)
SMIL helper to load next chunk ("<...>" or untagged content) in buf.
Definition: subtitles.c:307
static int sami_read_header(AVFormatContext *s)
Definition: samidec.c:49
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
void * buf
Definition: avisynth_c.h:766
int ff_bprint_to_codecpar_extradata(AVCodecParameters *par, struct AVBPrint *buf)
Finalize buf into extradata and set its size appropriately.
Definition: utils.c:5700
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
#define flags(name, subs,...)
Definition: cbs_av1.c:561
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
void av_bprint_clear(AVBPrint *buf)
Reset the string to "" but keep internal allocated data.
Definition: bprint.c:227
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
Main libavformat public API header.
common internal api header.
void ff_text_init_buf(FFTextReader *r, void *buf, size_t size)
Similar to ff_text_init_avio(), but sets it up to read from a bounded buffer.
Definition: subtitles.c:53
static int sami_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: samidec.c:115
static int sami_read_close(AVFormatContext *s)
Definition: samidec.c:129
void * priv_data
Format private data.
Definition: avformat.h:1386
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
AVPacket * ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q, const uint8_t *event, size_t len, int merge)
Insert a new subtitle event.
Definition: subtitles.c:111
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:1454
void ff_subtitles_queue_finalize(void *log_ctx, FFDemuxSubtitlesQueue *q)
Set missing durations, sort subtitles by PTS (and then byte position), and drop duplicated events...
Definition: subtitles.c:193
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1470
FFDemuxSubtitlesQueue q
Definition: samidec.c:36