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 "demux.h"
28 #include "internal.h"
29 #include "subtitles.h"
30 
31 #define TSBASE 10000000
32 
33 typedef struct {
35 } MPSubContext;
36 
37 static int mpsub_probe(const AVProbeData *p)
38 {
39  const char *ptr = p->buf;
40  const char *ptr_end = p->buf + p->buf_size;
41 
42  while (ptr < ptr_end) {
43  int inc;
44 
45  if (!memcmp(ptr, "FORMAT=TIME", 11))
47  if (!memcmp(ptr, "FORMAT=", 7))
48  return AVPROBE_SCORE_EXTENSION / 3;
49  inc = ff_subtitles_next_line(ptr);
50  if (!inc)
51  break;
52  ptr += inc;
53  }
54  return 0;
55 }
56 
57 static int parse_line(const char *line, int64_t *value, int64_t *value2)
58 {
59  int vi, p1, p2;
60 
61  for (vi = 0; vi < 2; vi++) {
62  long long intval, fracval;
63  int n = av_sscanf(line, "%lld%n.%lld%n", &intval, &p1, &fracval, &p2);
64  if (n <= 0 || intval < INT64_MIN / TSBASE || intval > INT64_MAX / TSBASE)
65  return AVERROR_INVALIDDATA;
66 
67  intval *= TSBASE;
68 
69  if (n == 2) {
70  if (fracval < 0)
71  return AVERROR_INVALIDDATA;
72  for (;p2 - p1 < 7 + 1; p1--)
73  fracval *= 10;
74  for (;p2 - p1 > 7 + 1; p1++)
75  fracval /= 10;
76  if (intval > 0) intval = av_sat_add64(intval, fracval);
77  else intval = av_sat_sub64(intval, fracval);
78  line += p2;
79  } else
80  line += p1;
81 
82  *value = intval;
83 
84  value = value2;
85  }
86 
87  return 0;
88 }
89 
91 {
92  MPSubContext *mpsub = s->priv_data;
93  AVStream *st;
94  AVBPrint buf;
95  AVRational pts_info = (AVRational){ TSBASE, 1 }; // ts based by default
96  int res = 0;
97  int64_t current_pts = 0;
98  int i;
99  int common_factor = 0;
100 
102 
103  while (!avio_feof(s->pb)) {
104  char line[1024];
105  int64_t start, duration;
106  int fps, len = ff_get_line(s->pb, line, sizeof(line));
107 
108  if (!len)
109  break;
110 
111  line[strcspn(line, "\r\n")] = 0;
112 
113  if (sscanf(line, "FORMAT=%d", &fps) == 1 && fps > 3 && fps < 100) {
114  /* frame based timing */
115  pts_info = (AVRational){ TSBASE * fps, 1 };
116  } else if (parse_line(line, &start, &duration) >= 0) {
117  AVPacket *sub;
118  const int64_t pos = avio_tell(s->pb);
119 
120  res = ff_subtitles_read_chunk(s->pb, &buf);
121  if (res < 0) goto end;
122  if (buf.len) {
123  sub = ff_subtitles_queue_insert_bprint(&mpsub->q, &buf, 0);
124  if (!sub) {
125  res = AVERROR(ENOMEM);
126  goto end;
127  }
128  if ( current_pts < 0 && start < INT64_MIN - current_pts
129  || current_pts > 0 && start > INT64_MAX - current_pts) {
130  res = AVERROR_INVALIDDATA;
131  goto end;
132  }
133  sub->pts = current_pts + start;
134  if (duration < 0 || sub->pts > INT64_MAX - duration) {
135  res = AVERROR_INVALIDDATA;
136  goto end;
137  }
138  sub->duration = duration;
139 
140  common_factor = av_gcd(duration, common_factor);
141  common_factor = av_gcd(sub->pts, common_factor);
142 
143  current_pts = sub->pts + duration;
144  sub->pos = pos;
145  }
146  }
147  }
148 
149  if (common_factor > 1) {
150  common_factor = av_gcd(pts_info.num, common_factor);
151  for (i = 0; i < mpsub->q.nb_subs; i++) {
152  mpsub->q.subs[i]->pts /= common_factor;
153  mpsub->q.subs[i]->duration /= common_factor;
154  }
155  pts_info.num /= common_factor;
156  }
157 
158  st = avformat_new_stream(s, NULL);
159  if (!st) {
160  res = AVERROR(ENOMEM);
161  goto end;
162  }
163  avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num);
166 
167  ff_subtitles_queue_finalize(s, &mpsub->q);
168 
169 end:
170  av_bprint_finalize(&buf, NULL);
171  return res;
172 }
173 
175  .p.name = "mpsub",
176  .p.long_name = NULL_IF_CONFIG_SMALL("MPlayer subtitles"),
177  .p.extensions = "sub",
178  .priv_data_size = sizeof(MPSubContext),
179  .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,
183  .read_seek2 = ff_subtitles_read_seek,
185 };
AVMEDIA_TYPE_SUBTITLE
@ AVMEDIA_TYPE_SUBTITLE
Definition: avutil.h:204
ff_subtitles_read_close
int ff_subtitles_read_close(AVFormatContext *s)
Definition: subtitles.c:337
AV_BPRINT_SIZE_UNLIMITED
#define AV_BPRINT_SIZE_UNLIMITED
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
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:51
av_bprint_init
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
Definition: bprint.c:69
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const struct AVCodec *c)
Add a new stream to a media file.
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:540
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:454
ff_subtitles_read_chunk
int ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
Same as ff_subtitles_read_text_chunk(), but read from an AVIOContext.
Definition: subtitles.c:437
av_gcd
int64_t av_gcd(int64_t a, int64_t b)
Compute the greatest common divisor of two integer operands.
Definition: mathematics.c:37
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: avformat.c:853
read_close
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:143
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:494
pts
static int64_t pts
Definition: transcode_aac.c:643
AVRational::num
int num
Numerator.
Definition: rational.h:59
ff_subtitles_read_packet
int ff_subtitles_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: subtitles.c:323
MPSubContext
Definition: mpsubdec.c:33
duration
int64_t duration
Definition: movenc.c:64
read_packet
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_read_callback.c:41
MPSubContext::q
FFDemuxSubtitlesQueue q
Definition: mpsubdec.c:34
s
#define s(width, name)
Definition: cbs_vp9.c:198
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:553
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:453
ff_mpsub_demuxer
const FFInputFormat ff_mpsub_demuxer
Definition: mpsubdec.c:174
mpsub_read_header
static int mpsub_read_header(AVFormatContext *s)
Definition: mpsubdec.c:90
FF_INFMT_FLAG_INIT_CLEANUP
#define FF_INFMT_FLAG_INIT_CLEANUP
For an FFInputFormat with this flag set read_close() needs to be called by the caller upon read_heade...
Definition: demux.h:35
AVFormatContext
Format I/O context.
Definition: avformat.h:1255
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:766
av_sscanf
int av_sscanf(const char *string, const char *format,...)
See libc sscanf manual for more information.
Definition: avsscanf.c:962
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:550
NULL
#define NULL
Definition: coverity.c:32
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:451
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:461
av_sat_sub64
#define av_sat_sub64
Definition: common.h:143
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:106
av_bprint_finalize
int av_bprint_finalize(AVBPrint *buf, char **ret_str)
Finalize a print buffer.
Definition: bprint.c:240
mpsub_probe
static int mpsub_probe(const AVProbeData *p)
Definition: mpsubdec.c:37
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:204
FFDemuxSubtitlesQueue
Definition: subtitles.h:103
FFInputFormat::p
AVInputFormat p
The public AVInputFormat.
Definition: demux.h:41
line
Definition: graph2dot.c:48
ff_subtitles_queue_insert_bprint
AVPacket * ff_subtitles_queue_insert_bprint(FFDemuxSubtitlesQueue *q, const AVBPrint *event, int merge)
Same as ff_subtitles_queue_insert but takes an AVBPrint input.
Definition: subtitles.c:148
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:255
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:515
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:329
ff_get_line
int ff_get_line(AVIOContext *s, char *buf, int maxlen)
Read a whole line of text from AVIOContext.
Definition: aviobuf.c:768
demux.h
len
int len
Definition: vorbis_enc_data.h:426
AVStream
Stream structure.
Definition: avformat.h:743
pos
unsigned int pos
Definition: spdifenc.c:413
avformat.h
AV_CODEC_ID_TEXT
@ AV_CODEC_ID_TEXT
raw UTF-8 text
Definition: codec_id.h:551
av_sat_add64
#define av_sat_add64
Definition: common.h:140
subtitles.h
AVRational::den
int den
Denominator.
Definition: rational.h:60
TSBASE
#define TSBASE
Definition: mpsubdec.c:31
read_probe
static int read_probe(const AVProbeData *p)
Definition: cdg.c:30
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:55
AVPacket
This structure stores compressed data.
Definition: packet.h:499
AVPacket::pos
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:542
FFInputFormat
Definition: demux.h:37
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:205
parse_line
static int parse_line(const char *line, int64_t *value, int64_t *value2)
Definition: mpsubdec.c:57
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:345