libavformat/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(AVProbeData *p)
40 {
41  const unsigned char *ptr = p->buf;
42 
43  if (AV_RB24(ptr) == 0xEFBBBF)
44  ptr += 3; /* skip UTF-8 BOM */
45  return !strncmp(ptr, "<SAMI>", 6) ? AVPROBE_SCORE_MAX : 0;
46 }
47 
49 {
50  SAMIContext *sami = s->priv_data;
52  AVBPrint buf, hdr_buf;
53  char c = 0;
54  int res = 0, got_first_sync_point = 0;
55 
56  if (!st)
57  return AVERROR(ENOMEM);
58  avpriv_set_pts_info(st, 64, 1, 1000);
61 
64 
65  while (!url_feof(s->pb)) {
66  AVPacket *sub;
67  const int64_t pos = avio_tell(s->pb) - (c != 0);
68  int is_sync, n = ff_smil_extract_next_chunk(s->pb, &buf, &c);
69 
70  if (n == 0)
71  break;
72 
73  is_sync = !av_strncasecmp(buf.str, "<SYNC", 5);
74  if (is_sync)
75  got_first_sync_point = 1;
76 
77  if (!got_first_sync_point) {
78  av_bprintf(&hdr_buf, "%s", buf.str);
79  } else {
80  sub = ff_subtitles_queue_insert(&sami->q, buf.str, buf.len, !is_sync);
81  if (!sub) {
82  res = AVERROR(ENOMEM);
83  goto end;
84  }
85  if (is_sync) {
86  const char *p = ff_smil_get_attr_ptr(buf.str, "Start");
87  sub->pos = pos;
88  sub->pts = p ? strtol(p, NULL, 10) : 0;
89  sub->duration = -1;
90  }
91  }
92  av_bprint_clear(&buf);
93  }
94 
95  res = avpriv_bprint_to_extradata(st->codec, &hdr_buf);
96  if (res < 0)
97  goto end;
98 
100 
101 end:
102  av_bprint_finalize(&buf, NULL);
103  return res;
104 }
105 
107 {
108  SAMIContext *sami = s->priv_data;
109  return ff_subtitles_queue_read_packet(&sami->q, pkt);
110 }
111 
112 static int sami_read_seek(AVFormatContext *s, int stream_index,
113  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
114 {
115  SAMIContext *sami = s->priv_data;
116  return ff_subtitles_queue_seek(&sami->q, s, stream_index,
117  min_ts, ts, max_ts, flags);
118 }
119 
121 {
122  SAMIContext *sami = s->priv_data;
123  ff_subtitles_queue_clean(&sami->q);
124  return 0;
125 }
126 
128  .name = "sami",
129  .long_name = NULL_IF_CONFIG_SMALL("SAMI subtitle format"),
130  .priv_data_size = sizeof(SAMIContext),
134  .read_seek2 = sami_read_seek,
136  .extensions = "smi,sami",
137 };
const char * s
Definition: avisynth_c.h:668
void av_bprintf(AVBPrint *buf, const char *fmt,...)
Definition: bprint.c:93
int64_t pos
byte position in stream, -1 if unknown
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.
static int sami_read_seek(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
#define AV_RB24
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:134
int av_strncasecmp(const char *a, const char *b, size_t n)
Locale-independent case-insensitive compare.
Definition: avstring.c:222
AVPacket * ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q, const uint8_t *event, int len, int merge)
Insert a new subtitle event.
Definition: subtitles.c:26
int av_bprint_finalize(AVBPrint *buf, char **ret_str)
Finalize a print buffer.
Definition: bprint.c:193
Format I/O context.
Definition: avformat.h:944
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:167
int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)
Generic read_packet() callback for subtitles demuxers using this queue system.
Definition: subtitles.c:82
static AVPacket pkt
Definition: demuxing.c:56
AVInputFormat ff_sami_demuxer
end end
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:145
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:248
int duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
int avpriv_bprint_to_extradata(AVCodecContext *avctx, struct AVBPrint *buf)
Finalize buf into extradata and set its size appropriately.
#define AV_BPRINT_SIZE_UNLIMITED
Convenience macros for special values for av_bprint_init() size_max parameter.
Definition: bprint.h:89
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
Init a print buffer.
Definition: bprint.c:68
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:662
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:336
Buffer to print data progressively.
Definition: bprint.h:75
static int read_probe(AVProbeData *pd)
static int sami_probe(AVProbeData *p)
int ff_smil_extract_next_chunk(AVIOContext *pb, AVBPrint *buf, char *c)
SMIL helper to load next chunk ("<...>" or untagged content) in buf.
Definition: subtitles.c:144
void ff_subtitles_queue_finalize(FFDemuxSubtitlesQueue *q)
Set missing durations and sort subtitles by PTS, and then byte position.
Definition: subtitles.c:72
int url_feof(AVIOContext *s)
feof() equivalent for AVIOContext.
Definition: aviobuf.c:280
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:517
Stream structure.
Definition: avformat.h:643
NULL
Definition: eval.c:55
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:95
enum AVMediaType codec_type
static int sami_read_header(AVFormatContext *s)
enum AVCodecID codec_id
AVIOContext * pb
I/O context.
Definition: avformat.h:977
void * buf
Definition: avisynth_c.h:594
static int read_packet(AVFormatContext *ctx, AVPacket *pkt)
Definition: libcdio.c:114
This structure contains the data a format has to probe a file.
Definition: avformat.h:334
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFilterBuffer 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.Buffer references ownership and permissions
static int flags
Definition: cpu.c:23
void av_bprint_clear(AVBPrint *buf)
Reset the string to "" but keep internal allocated data.
Definition: bprint.c:185
#define AVPROBE_SCORE_MAX
maximum score, half of that is used for file-extension-based detection
Definition: avformat.h:340
Main libavformat public API header.
common internal api header.
static double c[64]
static int sami_read_packet(AVFormatContext *s, AVPacket *pkt)
static int sami_read_close(AVFormatContext *s)
void * priv_data
Format private data.
Definition: avformat.h:964
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:461
This structure stores compressed data.
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
FFDemuxSubtitlesQueue q