FFmpeg
mpl2dec.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  * MPL2 subtitles format demuxer
24  */
25 
26 #include "libavutil/intreadwrite.h"
27 
28 #include "avformat.h"
29 #include "internal.h"
30 #include "subtitles.h"
31 
32 typedef struct {
34 } MPL2Context;
35 
36 static int mpl2_probe(const AVProbeData *p)
37 {
38  int i;
39  char c;
40  int64_t start, end;
41  const unsigned char *ptr = p->buf;
42  const unsigned char *ptr_end = ptr + p->buf_size;
43 
44  if (AV_RB24(ptr) == 0xefbbbf)
45  ptr += 3;
46 
47  for (i = 0; i < 2; i++) {
48  if (sscanf(ptr, "[%"SCNd64"][%"SCNd64"]%c", &start, &end, &c) != 3 &&
49  sscanf(ptr, "[%"SCNd64"][]%c", &start, &c) != 2)
50  return 0;
51  ptr += ff_subtitles_next_line(ptr);
52  if (ptr >= ptr_end)
53  return 0;
54  }
55  return AVPROBE_SCORE_MAX;
56 }
57 
58 static int read_ts(char **line, int64_t *pts_start, int *duration)
59 {
60  char c;
61  int len;
62  int64_t end;
63 
64  if (sscanf(*line, "[%"SCNd64"][]%c%n",
65  pts_start, &c, &len) >= 2) {
66  *duration = -1;
67  *line += len - 1;
68  return 0;
69  }
70  if (sscanf(*line, "[%"SCNd64"][%"SCNd64"]%c%n",
71  pts_start, &end, &c, &len) >= 3) {
72  *duration = end - *pts_start;
73  *line += len - 1;
74  return 0;
75  }
76  return -1;
77 }
78 
80 {
81  MPL2Context *mpl2 = s->priv_data;
83  int res = 0;
84 
85  if (!st)
86  return AVERROR(ENOMEM);
87  avpriv_set_pts_info(st, 64, 1, 10);
90 
91  if (avio_rb24(s->pb) != 0xefbbbf)
92  avio_seek(s->pb, -3, SEEK_CUR);
93 
94  while (!avio_feof(s->pb)) {
95  char line[4096];
96  char *p = line;
97  const int64_t pos = avio_tell(s->pb);
98  int len = ff_get_line(s->pb, line, sizeof(line));
99  int64_t pts_start;
100  int duration;
101 
102  if (!len)
103  break;
104 
105  line[strcspn(line, "\r\n")] = 0;
106 
107  if (!read_ts(&p, &pts_start, &duration)) {
108  AVPacket *sub;
109 
110  sub = ff_subtitles_queue_insert(&mpl2->q, p, strlen(p), 0);
111  if (!sub)
112  return AVERROR(ENOMEM);
113  sub->pos = pos;
114  sub->pts = pts_start;
115  sub->duration = duration;
116  }
117  }
118 
119  ff_subtitles_queue_finalize(s, &mpl2->q);
120  return res;
121 }
122 
124 {
125  MPL2Context *mpl2 = s->priv_data;
126  return ff_subtitles_queue_read_packet(&mpl2->q, pkt);
127 }
128 
129 static int mpl2_read_seek(AVFormatContext *s, int stream_index,
130  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
131 {
132  MPL2Context *mpl2 = s->priv_data;
133  return ff_subtitles_queue_seek(&mpl2->q, s, stream_index,
134  min_ts, ts, max_ts, flags);
135 }
136 
138 {
139  MPL2Context *mpl2 = s->priv_data;
140  ff_subtitles_queue_clean(&mpl2->q);
141  return 0;
142 }
143 
145  .name = "mpl2",
146  .long_name = NULL_IF_CONFIG_SMALL("MPL2 subtitles"),
147  .priv_data_size = sizeof(MPL2Context),
151  .read_seek2 = mpl2_read_seek,
153  .extensions = "txt,mpl2",
154 };
#define NULL
Definition: coverity.c:32
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:4892
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3957
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:246
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:297
static AVPacket pkt
Format I/O context.
Definition: avformat.h:1358
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
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4465
int64_t duration
Definition: movenc.c:63
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:557
AVInputFormat ff_mpl2_demuxer
Definition: mpl2dec.c:144
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3953
Definition: graph2dot.c:48
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
unsigned int avio_rb24(AVIOContext *s)
Definition: aviobuf.c:796
#define s(width, name)
Definition: cbs_vp9.c:257
int ff_get_line(AVIOContext *s, char *buf, int maxlen)
Read a whole line of text from AVIOContext.
Definition: aviobuf.c:811
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:530
static int mpl2_read_header(AVFormatContext *s)
Definition: mpl2dec.c:79
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
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_RB24
Definition: bytestream.h:87
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
FFDemuxSubtitlesQueue q
Definition: mpl2dec.c:33
static int mpl2_probe(const AVProbeData *p)
Definition: mpl2dec.c:36
static int mpl2_read_close(AVFormatContext *s)
Definition: mpl2dec.c:137
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
static int mpl2_read_seek(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Definition: mpl2dec.c:129
#define flags(name, subs,...)
Definition: cbs_av1.c:561
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:187
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
Main libavformat public API header.
static int mpl2_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: mpl2dec.c:123
The official guide to swscale for confused that consecutive non overlapping rectangles of slice_bottom special converter These generally are unscaled converters of common like for each output line the vertical scaler pulls lines from a ring buffer When the ring buffer does not contain the wanted line
Definition: swscale.txt:33
static int read_ts(char **line, int64_t *pts_start, int *duration)
Definition: mpl2dec.c:58
int len
void * priv_data
Format private data.
Definition: avformat.h:1386
void INT64 start
Definition: avisynth_c.h:766
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
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:361
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