FFmpeg  4.3.6
sccdec.c
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1 /*
2  * SCC subtitle demuxer
3  * Copyright (c) 2017 Paul B Mahol
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "avformat.h"
23 #include "internal.h"
24 #include "subtitles.h"
25 #include "libavutil/avstring.h"
26 #include "libavutil/bprint.h"
27 #include "libavutil/intreadwrite.h"
28 
29 typedef struct SCCContext {
31 } SCCContext;
32 
33 static int scc_probe(const AVProbeData *p)
34 {
35  char buf[18];
36  FFTextReader tr;
37 
38  ff_text_init_buf(&tr, p->buf, p->buf_size);
39 
40  while (ff_text_peek_r8(&tr) == '\r' || ff_text_peek_r8(&tr) == '\n')
41  ff_text_r8(&tr);
42 
43  ff_text_read(&tr, buf, sizeof(buf));
44 
45  if (!memcmp(buf, "Scenarist_SCC V1.0", 18))
46  return AVPROBE_SCORE_MAX;
47 
48  return 0;
49 }
50 
51 static int convert(uint8_t x)
52 {
53  if (x >= 'a')
54  x -= 87;
55  else if (x >= 'A')
56  x -= 55;
57  else
58  x -= '0';
59  return x;
60 }
61 
63 {
64  SCCContext *scc = s->priv_data;
66  char line[4096], line2[4096];
67  int64_t ts_start, ts_end;
68  int count = 0, ret = 0;
69  ptrdiff_t len2, len;
70  uint8_t out[4096];
71  FFTextReader tr;
72 
73  ff_text_init_avio(s, &tr, s->pb);
74 
75  if (!st)
76  return AVERROR(ENOMEM);
77  avpriv_set_pts_info(st, 64, 1, 1000);
80 
81  while (!ff_text_eof(&tr)) {
82  int64_t current_pos, next_pos;
83  char *saveptr = NULL, *lline;
84  int hh1, mm1, ss1, fs1, i;
85  int hh2, mm2, ss2, fs2;
86  AVPacket *sub;
87 
88  if (count == 0) {
89  current_pos = ff_text_pos(&tr);
90  while (!ff_text_eof(&tr)) {
91  len = ff_subtitles_read_line(&tr, line, sizeof(line));
92  if (len > 13)
93  break;
94  }
95  }
96 
97  if (!strncmp(line, "Scenarist_SCC V1.0", 18))
98  continue;
99  if (av_sscanf(line, "%d:%d:%d%*[:;]%d", &hh1, &mm1, &ss1, &fs1) != 4)
100  continue;
101 
102  ts_start = (hh1 * 3600LL + mm1 * 60LL + ss1) * 1000LL + fs1 * 33;
103 
104  next_pos = ff_text_pos(&tr);
105  while (!ff_text_eof(&tr)) {
106  len2 = ff_subtitles_read_line(&tr, line2, sizeof(line2));
107  if (len2 > 13)
108  break;
109  }
110  if (av_sscanf(line2, "%d:%d:%d%*[:;]%d", &hh2, &mm2, &ss2, &fs2) != 4)
111  continue;
112 
113  ts_end = (hh2 * 3600LL + mm2 * 60LL + ss2) * 1000LL + fs2 * 33;
114  count++;
115 
116 try_again:
117  lline = (char *)&line;
118  lline += 12;
119 
120  for (i = 0; i < 4095; i += 3) {
121  char *ptr = av_strtok(lline, " ", &saveptr);
122  char c1, c2, c3, c4;
123 
124  if (!ptr)
125  break;
126 
127  if (av_sscanf(ptr, "%c%c%c%c", &c1, &c2, &c3, &c4) != 4)
128  break;
129 
130  lline = NULL;
131  out[i+0] = 0xfc;
132  out[i+1] = convert(c2) | (convert(c1) << 4);
133  out[i+2] = convert(c4) | (convert(c3) << 4);
134  }
135  out[i] = 0;
136 
137  sub = ff_subtitles_queue_insert(&scc->q, out, i, 0);
138  if (!sub)
139  goto fail;
140 
141  sub->pos = current_pos;
142  sub->pts = ts_start;
143  sub->duration = ts_end - ts_start;
144  memmove(line, line2, sizeof(line));
145  current_pos = next_pos;
146  line2[0] = 0;
147  }
148 
149  if (line[0]) {
150  ts_start = ts_end;
151  ts_end += 1200;
152  goto try_again;
153  }
154 
155  ff_subtitles_queue_finalize(s, &scc->q);
156 
157  return ret;
158 fail:
160  return AVERROR(ENOMEM);
161 }
162 
164 {
165  SCCContext *scc = s->priv_data;
166  return ff_subtitles_queue_read_packet(&scc->q, pkt);
167 }
168 
169 static int scc_read_seek(AVFormatContext *s, int stream_index,
170  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
171 {
172  SCCContext *scc = s->priv_data;
173  return ff_subtitles_queue_seek(&scc->q, s, stream_index,
174  min_ts, ts, max_ts, flags);
175 }
176 
178 {
179  SCCContext *scc = s->priv_data;
181  return 0;
182 }
183 
185  .name = "scc",
186  .long_name = NULL_IF_CONFIG_SMALL("Scenarist Closed Captions"),
187  .priv_data_size = sizeof(SCCContext),
191  .read_seek2 = scc_read_seek,
193  .extensions = "scc",
194 };
#define NULL
Definition: coverity.c:32
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:375
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:4948
static int scc_read_close(AVFormatContext *s)
Definition: sccdec.c:177
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:302
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
Format I/O context.
Definition: avformat.h:1351
static int scc_read_header(AVFormatContext *s)
Definition: sccdec.c:62
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:212
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:373
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4526
static const uint64_t c1
Definition: murmur3.c:49
FFDemuxSubtitlesQueue q
Definition: sccdec.c:30
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:145
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
int ff_text_eof(FFTextReader *r)
Return non-zero if EOF was reached.
Definition: subtitles.c:92
#define AVERROR(e)
Definition: error.h:43
ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size)
Read a line of text.
Definition: subtitles.c:411
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:188
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
Definition: graph2dot.c:48
#define fail()
Definition: checkasm.h:123
int av_sscanf(const char *string, const char *format,...)
See libc sscanf manual for more information.
Definition: avsscanf.c:962
void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb)
Initialize the FFTextReader from the given AVIOContext.
Definition: subtitles.c:27
static int scc_probe(const AVProbeData *p)
Definition: sccdec.c:33
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:444
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
int64_t ff_text_pos(FFTextReader *r)
Return the byte position of the next byte returned by ff_text_r8().
Definition: subtitles.c:60
AVInputFormat ff_scc_demuxer
Definition: sccdec.c:184
static int scc_read_seek(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Definition: sccdec.c:169
#define s(width, name)
Definition: cbs_vp9.c:257
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 convert(uint8_t x)
Definition: sccdec.c:51
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:545
int ff_text_r8(FFTextReader *r)
Return the next byte.
Definition: subtitles.c:65
Stream structure.
Definition: avformat.h:876
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:250
AVIOContext * pb
I/O context.
Definition: avformat.h:1393
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
#define flags(name, subs,...)
Definition: cbs_av1.c:565
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
char * av_strtok(char *s, const char *delim, char **saveptr)
Split the string into several tokens which can be accessed by successive calls to av_strtok()...
Definition: avstring.c:184
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:453
Main libavformat public 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
static const uint64_t c2
Definition: murmur3.c:50
int len
void * priv_data
Format private data.
Definition: avformat.h:1379
FILE * out
Definition: movenc.c:54
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:650
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1023
static int scc_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: sccdec.c:163
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
This structure stores compressed data.
Definition: packet.h:332
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:194
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:348