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 
157  if (res < 0)
158  goto end;
159 
161 
162 end:
163  if (res < 0)
164  ass_read_close(s);
167  av_bprint_finalize(&rline, NULL);
168  return res;
169 }
170 
172 {
173  ASSContext *ass = s->priv_data;
174  return ff_subtitles_queue_read_packet(&ass->q, pkt);
175 }
176 
177 static int ass_read_seek(AVFormatContext *s, int stream_index,
178  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
179 {
180  ASSContext *ass = s->priv_data;
181  return ff_subtitles_queue_seek(&ass->q, s, stream_index,
182  min_ts, ts, max_ts, flags);
183 }
184 
186  .name = "ass",
187  .long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
188  .priv_data_size = sizeof(ASSContext),
193  .read_seek2 = ass_read_seek,
194 };
ass_probe
static int ass_probe(const AVProbeData *p)
Definition: assdec.c:36
AVMEDIA_TYPE_SUBTITLE
@ AVMEDIA_TYPE_SUBTITLE
Definition: avutil.h:204
AV_BPRINT_SIZE_UNLIMITED
#define AV_BPRINT_SIZE_UNLIMITED
ff_text_r8
int ff_text_r8(FFTextReader *r)
Return the next byte.
Definition: subtitles.c:65
ff_ass_demuxer
AVInputFormat ff_ass_demuxer
Definition: assdec.c:185
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:4553
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:235
av_bprint_init
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
Definition: bprint.c:69
ass_read_close
static int ass_read_close(AVFormatContext *s)
Definition: assdec.c:53
sub
static float sub(float src0, float src1)
Definition: dnn_backend_native_layer_mathbinary.c:32
internal.h
ass_read_header
static int ass_read_header(AVFormatContext *s)
Definition: assdec.c:111
FFDemuxSubtitlesQueue::keep_duplicates
int keep_duplicates
set to 1 to keep duplicated subtitle events
Definition: subtitles.h:108
ASSContext::readorder
unsigned readorder
Definition: assdec.c:33
FFTextReader
Definition: subtitles.h:40
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:444
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:5809
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:453
AV_CODEC_ID_ASS
@ AV_CODEC_ID_ASS
Definition: codec_id.h:546
read_close
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:145
ff_subtitles_queue_seek
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:255
pkt
AVPacket * pkt
Definition: movenc.c:59
ass_read_seek
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:177
AVInputFormat
Definition: avformat.h:640
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:53
duration
int64_t duration
Definition: movenc.c:64
ASSContext::q
FFDemuxSubtitlesQueue q
Definition: assdec.c:32
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:645
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
ff_subtitles_queue_read_packet
int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)
Generic read_packet() callback for subtitles demuxers using this queue system.
Definition: subtitles.c:216
ass_read_packet
static int ass_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: assdec.c:171
AVFormatContext
Format I/O context.
Definition: avformat.h:1231
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:86
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1038
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
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
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:111
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:27
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
avpriv_set_pts_info
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:4999
get_line
static int64_t get_line(AVBPrint *buf, FFTextReader *tr)
Definition: assdec.c:95
AV_NOPTS_VALUE
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
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:198
FFDemuxSubtitlesQueue
Definition: subtitles.h:102
header
static const uint8_t header[24]
Definition: sdr2.c:67
ff_subtitles_queue_clean
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:307
line
Definition: graph2dot.c:48
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:60
uint8_t
uint8_t
Definition: audio_convert.c:194
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:873
pos
unsigned int pos
Definition: spdifenc.c:412
avformat.h
av_bprintf
void av_bprintf(AVBPrint *buf, const char *fmt,...)
Definition: bprint.c:94
ff_text_peek_r8
int ff_text_peek_r8(FFTextReader *r)
Like ff_text_r8(), but don't remove the byte from the buffer.
Definition: subtitles.c:97
av_bprint_clear
void av_bprint_clear(AVBPrint *buf)
Reset the string to "" but keep internal allocated data.
Definition: bprint.c:227
subtitles.h
ASSContext
Definition: assdec.c:31
read_dialogue
static int read_dialogue(ASSContext *ass, AVBPrint *dst, const uint8_t *p, int64_t *start, int *duration)
Definition: assdec.c:60
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:346
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
av_bprint_chars
void av_bprint_chars(AVBPrint *buf, char c, unsigned n)
Append char c n times to a print buffer.
Definition: bprint.c:140
line
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:40