FFmpeg
assdec.c
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1 /*
2  * SSA/ASS demuxer
3  * Copyright (c) 2008 Michael Niedermayer
4  * Copyright (c) 2014 Clément Bœsch
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include <stdint.h>
24 
25 #include "avformat.h"
26 #include "internal.h"
27 #include "subtitles.h"
28 #include "libavcodec/internal.h"
29 #include "libavutil/bprint.h"
30 
31 typedef struct ASSContext {
33  unsigned readorder;
34 } ASSContext;
35 
36 static int ass_probe(const AVProbeData *p)
37 {
38  char buf[13];
39  FFTextReader tr;
40  ff_text_init_buf(&tr, p->buf, p->buf_size);
41 
42  while (ff_text_peek_r8(&tr) == '\r' || ff_text_peek_r8(&tr) == '\n')
43  ff_text_r8(&tr);
44 
45  ff_text_read(&tr, buf, sizeof(buf));
46 
47  if (!memcmp(buf, "[Script Info]", 13))
48  return AVPROBE_SCORE_MAX;
49 
50  return 0;
51 }
52 
54 {
55  ASSContext *ass = s->priv_data;
57  return 0;
58 }
59 
60 static int read_dialogue(ASSContext *ass, AVBPrint *dst, const uint8_t *p,
61  int64_t *start, int *duration)
62 {
63  int pos = 0;
64  int64_t end;
65  int hh1, mm1, ss1, ms1;
66  int hh2, mm2, ss2, ms2;
67 
68  if (sscanf(p, "Dialogue: %*[^,],%d:%d:%d%*c%d,%d:%d:%d%*c%d,%n",
69  &hh1, &mm1, &ss1, &ms1,
70  &hh2, &mm2, &ss2, &ms2, &pos) >= 8 && pos > 0) {
71 
72  /* This is not part of the sscanf itself in order to handle an actual
73  * number (which would be the Layer) or the form "Marked=N" (which is
74  * the old SSA field, now replaced by Layer, and will lead to Layer
75  * being 0 here). */
76  const int layer = atoi(p + 10);
77 
78  end = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
79  *start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
80  *duration = end - *start;
81 
82  av_bprint_clear(dst);
83  av_bprintf(dst, "%u,%d,%s", ass->readorder++, layer, p + pos);
84 
85  /* right strip the buffer */
86  while (dst->len > 0 &&
87  dst->str[dst->len - 1] == '\r' ||
88  dst->str[dst->len - 1] == '\n')
89  dst->str[--dst->len] = 0;
90  return 0;
91  }
92  return -1;
93 }
94 
95 static int64_t get_line(AVBPrint *buf, FFTextReader *tr)
96 {
97  int64_t pos = ff_text_pos(tr);
98 
99  av_bprint_clear(buf);
100  for (;;) {
101  char c = ff_text_r8(tr);
102  if (!c)
103  break;
104  av_bprint_chars(buf, c, 1);
105  if (c == '\n')
106  break;
107  }
108  return pos;
109 }
110 
112 {
113  ASSContext *ass = s->priv_data;
114  AVBPrint header, line, rline;
115  int res = 0;
116  AVStream *st;
117  FFTextReader tr;
118  ff_text_init_avio(s, &tr, s->pb);
119 
120  st = avformat_new_stream(s, NULL);
121  if (!st)
122  return AVERROR(ENOMEM);
123  avpriv_set_pts_info(st, 64, 1, 100);
126 
130 
131  ass->q.keep_duplicates = 1;
132 
133  for (;;) {
134  int64_t pos = get_line(&line, &tr);
135  int64_t ts_start = AV_NOPTS_VALUE;
136  int duration = -1;
137  AVPacket *sub;
138 
139  if (!line.str[0]) // EOF
140  break;
141 
142  if (read_dialogue(ass, &rline, line.str, &ts_start, &duration) < 0) {
143  av_bprintf(&header, "%s", line.str);
144  continue;
145  }
146  sub = ff_subtitles_queue_insert(&ass->q, rline.str, rline.len, 0);
147  if (!sub) {
148  res = AVERROR(ENOMEM);
149  goto end;
150  }
151  sub->pos = pos;
152  sub->pts = ts_start;
153  sub->duration = duration;
154  }
155 
156  res = ff_bprint_to_codecpar_extradata(st->codecpar, &header);
157  if (res < 0)
158  goto end;
159 
160  ff_subtitles_queue_finalize(s, &ass->q);
161 
162 end:
163  av_bprint_finalize(&header, NULL);
164  av_bprint_finalize(&line, NULL);
165  av_bprint_finalize(&rline, NULL);
166  return res;
167 }
168 
170 {
171  ASSContext *ass = s->priv_data;
172  return ff_subtitles_queue_read_packet(&ass->q, pkt);
173 }
174 
175 static int ass_read_seek(AVFormatContext *s, int stream_index,
176  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
177 {
178  ASSContext *ass = s->priv_data;
179  return ff_subtitles_queue_seek(&ass->q, s, stream_index,
180  min_ts, ts, max_ts, flags);
181 }
182 
184  .name = "ass",
185  .long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
186  .priv_data_size = sizeof(ASSContext),
191  .read_seek2 = ass_read_seek,
192 };
int keep_duplicates
set to 1 to keep duplicated subtitle events
Definition: subtitles.h:108
#define NULL
Definition: coverity.c:32
void av_bprintf(AVBPrint *buf, const char *fmt,...)
Definition: bprint.c:94
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
AVInputFormat ff_ass_demuxer
Definition: assdec.c:183
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3957
static int ass_read_close(AVFormatContext *s)
Definition: assdec.c:53
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:297
int ff_text_peek_r8(FFTextReader *r)
Like ff_text_r8(), but don&#39;t remove the byte from the buffer.
Definition: subtitles.c:97
static AVPacket pkt
int av_bprint_finalize(AVBPrint *buf, char **ret_str)
Finalize a print buffer.
Definition: bprint.c:235
unsigned readorder
Definition: assdec.c:33
Format I/O context.
Definition: avformat.h:1358
static int ass_read_header(AVFormatContext *s)
Definition: assdec.c:111
uint8_t
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 const uint8_t header[24]
Definition: sdr2.c:67
static int ass_read_seek(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Definition: assdec.c:175
#define AV_BPRINT_SIZE_UNLIMITED
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
Definition: bprint.c:69
FFDemuxSubtitlesQueue q
Definition: assdec.c:32
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3953
static int ass_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: assdec.c:169
void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb)
Initialize the FFTextReader from the given AVIOContext.
Definition: subtitles.c:27
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
int64_t ff_text_pos(FFTextReader *r)
Return the byte position of the next byte returned by ff_text_r8().
Definition: subtitles.c:60
#define s(width, name)
Definition: cbs_vp9.c:257
static int64_t get_line(AVBPrint *buf, FFTextReader *tr)
Definition: assdec.c:95
void ff_text_read(FFTextReader *r, char *buf, size_t size)
Read the given number of bytes (in UTF-8).
Definition: subtitles.c:86
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:530
int ff_text_r8(FFTextReader *r)
Return the next byte.
Definition: subtitles.c:65
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
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
void * buf
Definition: avisynth_c.h:766
int ff_bprint_to_codecpar_extradata(AVCodecParameters *par, struct AVBPrint *buf)
Finalize buf into extradata and set its size appropriately.
Definition: utils.c:5710
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
#define flags(name, subs,...)
Definition: cbs_av1.c:561
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
void av_bprint_clear(AVBPrint *buf)
Reset the string to "" but keep internal allocated data.
Definition: bprint.c:227
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
Main libavformat public API header.
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
common internal api header.
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:53
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
static int ass_probe(const AVProbeData *p)
Definition: assdec.c:36
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
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
static int read_dialogue(ASSContext *ass, AVBPrint *dst, const uint8_t *p, int64_t *start, int *duration)
Definition: assdec.c:60
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
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
void av_bprint_chars(AVBPrint *buf, char c, unsigned n)
Append char c n times to a print buffer.
Definition: bprint.c:140