FFmpeg  4.4.6
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  AVPacket *sub = NULL;
67  ptrdiff_t len;
68  uint8_t out[4096];
69  FFTextReader tr;
70 
71  ff_text_init_avio(s, &tr, s->pb);
72 
73  if (!st)
74  return AVERROR(ENOMEM);
75  avpriv_set_pts_info(st, 64, 1, 1000);
78 
79  while (1) {
80  char *saveptr = NULL, *lline;
81  int hh, mm, ss, fs, i;
82  char line[4096];
83  int64_t pos, ts;
84 
85  len = ff_subtitles_read_line(&tr, line, sizeof(line));
86  if (len <= 13) {
87  if (ff_text_eof(&tr))
88  break;
89  continue;
90  }
91  if (!strncmp(line, "Scenarist_SCC V1.0", 18))
92  continue;
93  if (av_sscanf(line, "%d:%d:%d%*[:;]%d", &hh, &mm, &ss, &fs) != 4)
94  continue;
95 
96  ts = (hh * 3600LL + mm * 60LL + ss) * 1000LL + fs * 33LL;
97  if (sub)
98  sub->duration = ts - sub->pts;
99 
100  pos = ff_text_pos(&tr);
101  lline = (char *)&line;
102  lline += 12;
103 
104  for (i = 0; i < 4095; i += 3) {
105  char *ptr = av_strtok(lline, " ", &saveptr);
106  char c1, c2, c3, c4;
107  uint8_t o1, o2;
108 
109  if (!ptr)
110  break;
111 
112  if (av_sscanf(ptr, "%c%c%c%c", &c1, &c2, &c3, &c4) != 4)
113  break;
114  o1 = convert(c2) | (convert(c1) << 4);
115  o2 = convert(c4) | (convert(c3) << 4);
116 
117  lline = NULL;
118 
119  if (i > 12 && o1 == 0x94 && o2 == 0x20 && saveptr &&
120  (av_strncasecmp(saveptr, "942f", 4) && !av_strncasecmp(saveptr, "942c", 4))) {
121 
122  out[i] = 0;
123 
124  sub = ff_subtitles_queue_insert(&scc->q, out, i, 0);
125  if (!sub)
126  goto fail;
127 
128  sub->pos = pos;
129  pos += i;
130  sub->pts = ts;
131  sub->duration = i * 11;
132  ts += sub->duration;
133  i = 0;
134  }
135 
136  out[i+0] = 0xfc;
137  out[i+1] = o1;
138  out[i+2] = o2;
139  }
140 
141  out[i] = 0;
142 
143  sub = ff_subtitles_queue_insert(&scc->q, out, i, 0);
144  if (!sub)
145  goto fail;
146 
147  sub->pos = pos;
148  sub->pts = ts;
149  }
150 
152 
153  return 0;
154 fail:
156  return AVERROR(ENOMEM);
157 }
158 
160 {
161  SCCContext *scc = s->priv_data;
162  return ff_subtitles_queue_read_packet(&scc->q, pkt);
163 }
164 
165 static int scc_read_seek(AVFormatContext *s, int stream_index,
166  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
167 {
168  SCCContext *scc = s->priv_data;
169  return ff_subtitles_queue_seek(&scc->q, s, stream_index,
170  min_ts, ts, max_ts, flags);
171 }
172 
174 {
175  SCCContext *scc = s->priv_data;
177  return 0;
178 }
179 
181  .name = "scc",
182  .long_name = NULL_IF_CONFIG_SMALL("Scenarist Closed Captions"),
183  .priv_data_size = sizeof(SCCContext),
187  .read_seek2 = scc_read_seek,
189  .extensions = "scc",
190 };
uint8_t
Main libavformat public API header.
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:453
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
#define flags(name, subs,...)
Definition: cbs_av1.c:572
#define ss(width, name, subs,...)
Definition: cbs_vp9.c:261
#define s(width, name)
Definition: cbs_vp9.c:257
#define fs(width, name, subs,...)
Definition: cbs_vp9.c:259
#define fail()
Definition: checkasm.h:133
#define NULL
Definition: coverity.c:32
long long int64_t
Definition: coverity.c:34
static float sub(float src0, float src1)
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:545
@ AV_CODEC_ID_EIA_608
Definition: codec_id.h:534
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4509
#define AVERROR(e)
Definition: error.h:43
@ AVMEDIA_TYPE_SUBTITLE
Definition: avutil.h:204
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:186
int av_sscanf(const char *string, const char *format,...)
See libc sscanf manual for more information.
Definition: avsscanf.c:962
int av_strncasecmp(const char *a, const char *b, size_t n)
Locale-independent case-insensitive compare.
Definition: avstring.c:225
int i
Definition: input.c:407
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:4945
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
common internal API header
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:145
static const uint64_t c2
Definition: murmur3.c:52
static const uint64_t c1
Definition: murmur3.c:51
static int scc_probe(const AVProbeData *p)
Definition: sccdec.c:33
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:165
static int scc_read_close(AVFormatContext *s)
Definition: sccdec.c:173
static int convert(uint8_t x)
Definition: sccdec.c:51
static int scc_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: sccdec.c:159
AVInputFormat ff_scc_demuxer
Definition: sccdec.c:180
static int scc_read_header(AVFormatContext *s)
Definition: sccdec.c:62
unsigned int pos
Definition: spdifenc.c:412
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
Format I/O context.
Definition: avformat.h:1232
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:645
This structure stores compressed data.
Definition: packet.h:346
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
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
Stream structure.
Definition: avformat.h:873
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1038
FFDemuxSubtitlesQueue q
Definition: sccdec.c:30
Definition: graph2dot.c:48
ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size)
Read a line of text.
Definition: subtitles.c:416
int64_t ff_text_pos(FFTextReader *r)
Return the byte position of the next byte returned by ff_text_r8().
Definition: subtitles.c:60
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
void ff_text_read(FFTextReader *r, char *buf, size_t size)
Read the given number of bytes (in UTF-8).
Definition: subtitles.c:86
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
int ff_text_eof(FFTextReader *r)
Return non-zero if EOF was reached.
Definition: subtitles.c:92
void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb)
Initialize the FFTextReader from the given AVIOContext.
Definition: subtitles.c:27
int ff_text_r8(FFTextReader *r)
Return the next byte.
Definition: subtitles.c:65
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
int ff_text_peek_r8(FFTextReader *r)
Like ff_text_r8(), but don't remove the byte from the buffer.
Definition: subtitles.c:97
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
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:307
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
FILE * out
Definition: movenc.c:54
AVPacket * pkt
Definition: movenc.c:59
int len