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 "demux.h"
27 #include "internal.h"
28 #include "subtitles.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 
53 static int read_dialogue(ASSContext *ass, AVBPrint *dst, const uint8_t *p,
54  int64_t *start, int *duration)
55 {
56  int pos = 0;
57  int64_t end;
58  int hh1, mm1, ss1, ms1;
59  int hh2, mm2, ss2, ms2;
60 
61  if (sscanf(p, "Dialogue: %*[^,],%d:%d:%d%*c%d,%d:%d:%d%*c%d,%n",
62  &hh1, &mm1, &ss1, &ms1,
63  &hh2, &mm2, &ss2, &ms2, &pos) >= 8 && pos > 0) {
64 
65  /* This is not part of the sscanf itself in order to handle an actual
66  * number (which would be the Layer) or the form "Marked=N" (which is
67  * the old SSA field, now replaced by Layer, and will lead to Layer
68  * being 0 here). */
69  const int layer = atoi(p + 10);
70 
71  end = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
72  *start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
73  *duration = end - *start;
74 
75  av_bprint_clear(dst);
76  av_bprintf(dst, "%u,%d,%s", ass->readorder++, layer, p + pos);
77  if (!av_bprint_is_complete(dst))
78  return AVERROR(ENOMEM);
79 
80  /* right strip the buffer */
81  while (dst->len > 0 &&
82  dst->str[dst->len - 1] == '\r' ||
83  dst->str[dst->len - 1] == '\n')
84  dst->str[--dst->len] = 0;
85  return 0;
86  }
87  return -1;
88 }
89 
90 static int64_t get_line(AVBPrint *buf, FFTextReader *tr)
91 {
92  int64_t pos = ff_text_pos(tr);
93 
94  av_bprint_clear(buf);
95  for (;;) {
96  char c = ff_text_r8(tr);
97  if (!c)
98  break;
99  av_bprint_chars(buf, c, 1);
100  if (c == '\n')
101  break;
102  }
103  return pos;
104 }
105 
107 {
108  ASSContext *ass = s->priv_data;
109  AVBPrint header, line, rline;
110  int res = 0;
111  AVStream *st;
112  FFTextReader tr;
113  ff_text_init_avio(s, &tr, s->pb);
114 
115  st = avformat_new_stream(s, NULL);
116  if (!st)
117  return AVERROR(ENOMEM);
118  avpriv_set_pts_info(st, 64, 1, 100);
121 
125 
126  ass->q.keep_duplicates = 1;
127 
128  for (;;) {
129  int64_t pos = get_line(&line, &tr);
130  int64_t ts_start = AV_NOPTS_VALUE;
131  int duration = -1;
132  AVPacket *sub;
133 
134  if (!line.str[0]) // EOF
135  break;
136 
137  if (read_dialogue(ass, &rline, line.str, &ts_start, &duration) < 0) {
138  av_bprintf(&header, "%s", line.str);
139  continue;
140  }
141  sub = ff_subtitles_queue_insert_bprint(&ass->q, &rline, 0);
142  if (!sub) {
143  res = AVERROR(ENOMEM);
144  goto end;
145  }
146  sub->pos = pos;
147  sub->pts = ts_start;
148  sub->duration = duration;
149  }
150 
152  if (res < 0)
153  goto end;
154 
156 
157 end:
160  av_bprint_finalize(&rline, NULL);
161  return res;
162 }
163 
165  .p.name = "ass",
166  .p.long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
167  .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,
168  .priv_data_size = sizeof(ASSContext),
173  .read_seek2 = ff_subtitles_read_seek,
174 };
ass_probe
static int ass_probe(const AVProbeData *p)
Definition: assdec.c:36
AVMEDIA_TYPE_SUBTITLE
@ AVMEDIA_TYPE_SUBTITLE
Definition: avutil.h:204
ff_subtitles_read_close
int ff_subtitles_read_close(AVFormatContext *s)
Definition: subtitles.c:345
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
av_bprint_is_complete
static int av_bprint_is_complete(const AVBPrint *buf)
Test if the print buffer is complete (not truncated).
Definition: bprint.h:218
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.
int64_t
long long int64_t
Definition: coverity.c:34
ass_read_header
static int ass_read_header(AVFormatContext *s)
Definition: assdec.c:106
FFDemuxSubtitlesQueue::keep_duplicates
int keep_duplicates
set to 1 to keep duplicated subtitle events
Definition: subtitles.h:109
ASSContext::readorder
unsigned readorder
Definition: assdec.c:33
AVPacket::duration
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:551
FFTextReader
Definition: subtitles.h:41
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:454
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:572
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:463
AV_CODEC_ID_ASS
@ AV_CODEC_ID_ASS
Definition: codec_id.h:572
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:855
read_close
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:143
ff_subtitles_read_packet
int ff_subtitles_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: subtitles.c:331
duration
int64_t duration
Definition: movenc.c:65
ASSContext::q
FFDemuxSubtitlesQueue q
Definition: assdec.c:32
read_packet
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_read_callback.c:42
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_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:1260
internal.h
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:771
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:550
NULL
#define NULL
Definition: coverity.c:32
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:451
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:28
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:94
av_bprint_finalize
int av_bprint_finalize(AVBPrint *buf, char **ret_str)
Finalize a print buffer.
Definition: bprint.c:240
get_line
static int64_t get_line(AVBPrint *buf, FFTextReader *tr)
Definition: assdec.c:90
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:212
FFDemuxSubtitlesQueue
Definition: subtitles.h:103
FFInputFormat::p
AVInputFormat p
The public AVInputFormat.
Definition: demux.h:41
header
static const uint8_t header[24]
Definition: sdr2.c:68
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:156
bprint.h
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:526
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
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:337
demux.h
AVStream
Stream structure.
Definition: avformat.h:748
pos
unsigned int pos
Definition: spdifenc.c:414
avformat.h
av_bprintf
void av_bprintf(AVBPrint *buf, const char *fmt,...)
Definition: bprint.c:99
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
subtitles.h
av_bprint_clear
void av_bprint_clear(AVBPrint *buf)
Reset the string to "" but keep internal allocated data.
Definition: bprint.c:232
ff_text_init_buf
void ff_text_init_buf(FFTextReader *r, const void *buf, size_t size)
Similar to ff_text_init_avio(), but sets it up to read from a bounded buffer.
Definition: subtitles.c:54
ff_ass_demuxer
const FFInputFormat ff_ass_demuxer
Definition: assdec.c:164
ASSContext
Definition: assdec.c:31
read_probe
static int read_probe(const AVProbeData *p)
Definition: cdg.c:30
read_dialogue
static int read_dialogue(ASSContext *ass, AVBPrint *dst, const uint8_t *p, int64_t *start, int *duration)
Definition: assdec.c:53
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:510
AVPacket::pos
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:553
FFInputFormat
Definition: demux.h:37
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:145
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