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  av_bprint_finalize(&hdr_buf, NULL);
93  goto end;
94  }
95  if (is_sync) {
96  const char *p = ff_smil_get_attr_ptr(buf.str, "Start");
97  sub->pos = pos;
98  sub->pts = p ? strtol(p, NULL, 10) : 0;
99  if (sub->pts <= INT64_MIN/2 || sub->pts >= INT64_MAX/2) {
100  res = AVERROR_PATCHWELCOME;
101  av_bprint_finalize(&hdr_buf, NULL);
102  goto end;
103  }
104 
105  sub->duration = -1;
106  }
107  }
108  av_bprint_clear(&buf);
109  }
110 
111  res = ff_bprint_to_codecpar_extradata(st->codecpar, &hdr_buf);
112  if (res < 0)
113  goto end;
114 
116 
117 end:
118  av_bprint_finalize(&buf, NULL);
119  return res;
120 }
121 
123  .name = "sami",
124  .long_name = NULL_IF_CONFIG_SMALL("SAMI subtitle format"),
125  .priv_data_size = sizeof(SAMIContext),
126  .flags_internal = FF_FMT_INIT_CLEANUP,
129  .extensions = "smi,sami",
131  .read_seek2 = ff_subtitles_read_seek,
133 };
AVMEDIA_TYPE_SUBTITLE
@ AVMEDIA_TYPE_SUBTITLE
Definition: avutil.h:204
ff_subtitles_read_close
int ff_subtitles_read_close(AVFormatContext *s)
Definition: subtitles.c:329
AV_BPRINT_SIZE_UNLIMITED
#define AV_BPRINT_SIZE_UNLIMITED
FF_FMT_INIT_CLEANUP
#define FF_FMT_INIT_CLEANUP
For an AVInputFormat with this flag set read_close() needs to be called by the caller upon read_heade...
Definition: internal.h:48
AVERROR
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
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:724
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
ff_smil_extract_next_text_chunk
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:336
av_bprint_finalize
int av_bprint_finalize(AVBPrint *buf, char **ret_str)
Finalize a print buffer.
Definition: bprint.c:234
av_bprint_init
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
Definition: bprint.c:68
sub
static float sub(float src0, float src1)
Definition: dnn_backend_native_layer_mathbinary.c:31
internal.h
FFTextReader
Definition: subtitles.h:41
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
sami_probe
static int sami_probe(const AVProbeData *p)
Definition: samidec.c:39
ff_bprint_to_codecpar_extradata
int ff_bprint_to_codecpar_extradata(AVCodecParameters *par, struct AVBPrint *buf)
Finalize buf into extradata and set its size appropriately.
Definition: utils.c:1860
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
read_close
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:141
AVInputFormat
Definition: avformat.h:626
ff_text_init_buf
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:52
ff_subtitles_read_packet
int ff_subtitles_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: subtitles.c:315
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:257
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:631
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
AVFormatContext
Format I/O context.
Definition: avformat.h:1097
ff_text_read
void ff_text_read(FFTextReader *r, char *buf, size_t size)
Read the given number of bytes (in UTF-8).
Definition: subtitles.c:84
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:992
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:527
NULL
#define NULL
Definition: coverity.c:32
AVERROR_PATCHWELCOME
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:64
read_probe
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
ff_subtitles_queue_insert
AVPacket * ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q, const uint8_t *event, size_t len, int merge)
Insert a new subtitle event.
Definition: subtitles.c:109
c
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
ff_text_init_avio
void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb)
Initialize the FFTextReader from the given AVIOContext.
Definition: subtitles.c:26
av_strncasecmp
int av_strncasecmp(const char *a, const char *b, size_t n)
Locale-independent case-insensitive compare.
Definition: avstring.c:225
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:117
SAMIContext::q
FFDemuxSubtitlesQueue q
Definition: samidec.c:36
ff_subtitles_queue_finalize
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:196
FFDemuxSubtitlesQueue
Definition: subtitles.h:103
bprint.h
ff_text_pos
int64_t ff_text_pos(FFTextReader *r)
Return the byte position of the next byte returned by ff_text_r8().
Definition: subtitles.c:58
AV_CODEC_ID_SAMI
@ AV_CODEC_ID_SAMI
Definition: codec_id.h:533
ff_subtitles_read_seek
int ff_subtitles_read_seek(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Definition: subtitles.c:321
read_packet
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
AVStream
Stream structure.
Definition: avformat.h:845
SAMIContext
Definition: samidec.c:33
pos
unsigned int pos
Definition: spdifenc.c:412
avformat.h
av_bprintf
void av_bprintf(AVBPrint *buf, const char *fmt,...)
Definition: bprint.c:93
av_bprint_clear
void av_bprint_clear(AVBPrint *buf)
Reset the string to "" but keep internal allocated data.
Definition: bprint.c:226
subtitles.h
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *st, 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:1146
sami_read_header
static int sami_read_header(AVFormatContext *s)
Definition: samidec.c:49
ff_text_eof
int ff_text_eof(FFTextReader *r)
Return non-zero if EOF was reached.
Definition: subtitles.c:90
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
AVPacket
This structure stores compressed data.
Definition: packet.h:350
avstring.h
ff_sami_demuxer
const AVInputFormat ff_sami_demuxer
Definition: samidec.c:122
ff_smil_get_attr_ptr
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:359