FFmpeg
mpsubdec.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  * MPlayer subtitles format demuxer
24  */
25 
26 #include "avformat.h"
27 #include "internal.h"
28 #include "subtitles.h"
29 
30 #define TSBASE 10000000
31 
32 typedef struct {
34 } MPSubContext;
35 
36 static int mpsub_probe(const AVProbeData *p)
37 {
38  const char *ptr = p->buf;
39  const char *ptr_end = p->buf + p->buf_size;
40 
41  while (ptr < ptr_end) {
42  int inc;
43 
44  if (!memcmp(ptr, "FORMAT=TIME", 11))
46  if (!memcmp(ptr, "FORMAT=", 7))
47  return AVPROBE_SCORE_EXTENSION / 3;
48  inc = ff_subtitles_next_line(ptr);
49  if (!inc)
50  break;
51  ptr += inc;
52  }
53  return 0;
54 }
55 
56 static int parse_line(const char *line, int64_t *value, int64_t *value2)
57 {
58  int vi, p1, p2;
59 
60  for (vi = 0; vi < 2; vi++) {
61  long long intval, fracval;
62  int n = av_sscanf(line, "%lld%n.%lld%n", &intval, &p1, &fracval, &p2);
63  if (n <= 0 || intval < INT64_MIN / TSBASE || intval > INT64_MAX / TSBASE)
64  return AVERROR_INVALIDDATA;
65 
66  intval *= TSBASE;
67 
68  if (n == 2) {
69  if (fracval < 0)
70  return AVERROR_INVALIDDATA;
71  for (;p2 - p1 < 7 + 1; p1--)
72  fracval *= 10;
73  for (;p2 - p1 > 7 + 1; p1++)
74  fracval /= 10;
75  if (intval > 0) intval = av_sat_add64(intval, fracval);
76  else intval = av_sat_sub64(intval, fracval);
77  line += p2;
78  } else
79  line += p1;
80 
81  *value = intval;
82 
83  value = value2;
84  }
85 
86  return 0;
87 }
88 
90 {
91  MPSubContext *mpsub = s->priv_data;
92  AVStream *st;
93  AVBPrint buf;
94  AVRational pts_info = (AVRational){ TSBASE, 1 }; // ts based by default
95  int res = 0;
96  int64_t current_pts = 0;
97  int i;
98  int common_factor = 0;
99 
101 
102  while (!avio_feof(s->pb)) {
103  char line[1024];
104  int64_t start, duration;
105  int fps, len = ff_get_line(s->pb, line, sizeof(line));
106 
107  if (!len)
108  break;
109 
110  line[strcspn(line, "\r\n")] = 0;
111 
112  if (sscanf(line, "FORMAT=%d", &fps) == 1 && fps > 3 && fps < 100) {
113  /* frame based timing */
114  pts_info = (AVRational){ TSBASE * fps, 1 };
115  } else if (parse_line(line, &start, &duration) >= 0) {
116  AVPacket *sub;
117  const int64_t pos = avio_tell(s->pb);
118 
119  ff_subtitles_read_chunk(s->pb, &buf);
120  if (buf.len) {
121  sub = ff_subtitles_queue_insert(&mpsub->q, buf.str, buf.len, 0);
122  if (!sub) {
123  res = AVERROR(ENOMEM);
124  goto end;
125  }
126  if ( current_pts < 0 && start < INT64_MIN - current_pts
127  || current_pts > 0 && start > INT64_MAX - current_pts) {
128  res = AVERROR_INVALIDDATA;
129  goto end;
130  }
131  sub->pts = current_pts + start;
132  if (duration < 0 || sub->pts > INT64_MAX - duration) {
133  res = AVERROR_INVALIDDATA;
134  goto end;
135  }
136  sub->duration = duration;
137 
138  common_factor = av_gcd(duration, common_factor);
139  common_factor = av_gcd(sub->pts, common_factor);
140 
141  current_pts = sub->pts + duration;
142  sub->pos = pos;
143  }
144  }
145  }
146 
147  if (common_factor > 1) {
148  common_factor = av_gcd(pts_info.num, common_factor);
149  for (i = 0; i < mpsub->q.nb_subs; i++) {
150  mpsub->q.subs[i]->pts /= common_factor;
151  mpsub->q.subs[i]->duration /= common_factor;
152  }
153  pts_info.num /= common_factor;
154  }
155 
156  st = avformat_new_stream(s, NULL);
157  if (!st) {
158  res = AVERROR(ENOMEM);
159  goto end;
160  }
161  avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num);
164 
165  ff_subtitles_queue_finalize(s, &mpsub->q);
166 
167 end:
168  av_bprint_finalize(&buf, NULL);
169  return res;
170 }
171 
173  .name = "mpsub",
174  .long_name = NULL_IF_CONFIG_SMALL("MPlayer subtitles"),
175  .priv_data_size = sizeof(MPSubContext),
176  .flags_internal = FF_FMT_INIT_CLEANUP,
179  .extensions = "sub",
181  .read_seek2 = ff_subtitles_read_seek,
183 };
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
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
FFDemuxSubtitlesQueue::nb_subs
int nb_subs
number of subtitles packets
Definition: subtitles.h:105
AVPacket::duration
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:391
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
av_gcd
int64_t av_gcd(int64_t a, int64_t b)
Compute the greatest common divisor of two integer operands.
Definition: mathematics.c:36
read_close
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:141
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:486
pts
static int64_t pts
Definition: transcode_aac.c:653
AVRational::num
int num
Numerator.
Definition: rational.h:59
AVInputFormat
Definition: avformat.h:638
ff_subtitles_read_packet
int ff_subtitles_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: subtitles.c:315
MPSubContext
Definition: mpsubdec.c:32
duration
int64_t duration
Definition: movenc.c:64
MPSubContext::q
FFDemuxSubtitlesQueue q
Definition: mpsubdec.c:33
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:643
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
mpsub_read_header
static int mpsub_read_header(AVFormatContext *s)
Definition: mpsubdec.c:89
AVFormatContext
Format I/O context.
Definition: avformat.h:1109
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1004
av_sscanf
int av_sscanf(const char *string, const char *format,...)
See libc sscanf manual for more information.
Definition: avsscanf.c:960
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:527
NULL
#define NULL
Definition: coverity.c:32
read_probe
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
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
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:456
av_sat_sub64
#define av_sat_sub64
Definition: common.h:141
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
mpsub_probe
static int mpsub_probe(const AVProbeData *p)
Definition: mpsubdec.c:36
ff_mpsub_demuxer
const AVInputFormat ff_mpsub_demuxer
Definition: mpsubdec.c:172
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
line
Definition: graph2dot.c:48
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:366
FFDemuxSubtitlesQueue::subs
AVPacket ** subs
array of subtitles packets
Definition: subtitles.h:104
value
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default value
Definition: writing_filters.txt:86
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
ff_get_line
int ff_get_line(AVIOContext *s, char *buf, int maxlen)
Read a whole line of text from AVIOContext.
Definition: aviobuf.c:781
len
int len
Definition: vorbis_enc_data.h:426
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:857
ff_subtitles_read_chunk
void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
Same as ff_subtitles_read_text_chunk(), but read from an AVIOContext.
Definition: subtitles.c:426
pos
unsigned int pos
Definition: spdifenc.c:412
avformat.h
AV_CODEC_ID_TEXT
@ AV_CODEC_ID_TEXT
raw UTF-8 text
Definition: codec_id.h:524
av_sat_add64
#define av_sat_add64
Definition: common.h:138
subtitles.h
AVRational::den
int den
Denominator.
Definition: rational.h:60
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
TSBASE
#define TSBASE
Definition: mpsubdec.c:30
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
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
ff_subtitles_next_line
static av_always_inline int ff_subtitles_next_line(const char *ptr)
Get the number of characters to increment to jump to the next line, or to the end of the string.
Definition: subtitles.h:195
parse_line
static int parse_line(const char *line, int64_t *value, int64_t *value2)
Definition: mpsubdec.c:56
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:360