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 {
30 FFDemuxSubtitlesQueue q;
31 } SCCContext;
32
scc_probe(const AVProbeData * p)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
convert(uint8_t x)51 static int convert(uint8_t x)
52 {
53 if (x >= 'a')
54 x -= 'a' - 10;
55 else if (x >= 'A')
56 x -= 'A' - 10;
57 else
58 x -= '0';
59 return x;
60 }
61
scc_read_header(AVFormatContext * s)62 static int scc_read_header(AVFormatContext *s)
63 {
64 SCCContext *scc = s->priv_data;
65 AVStream *st = avformat_new_stream(s, NULL);
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);
76 st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
77 st->codecpar->codec_id = AV_CODEC_ID_EIA_608;
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 pos = ff_text_pos(&tr);
86 len = ff_subtitles_read_line(&tr, line, sizeof(line));
87 if (len <= 13) {
88 if (ff_text_eof(&tr))
89 break;
90 continue;
91 }
92 if (av_sscanf(line, "%d:%d:%d%*[:;]%d", &hh, &mm, &ss, &fs) != 4)
93 continue;
94
95 ts = (hh * 3600LL + mm * 60LL + ss) * 1000LL + fs * 33LL;
96 if (sub)
97 sub->duration = ts - sub->pts;
98
99 lline = line;
100 lline += 12;
101
102 for (i = 0; i < 4095; i += 3) {
103 char *ptr = av_strtok(lline, " ", &saveptr);
104 char c1, c2, c3, c4;
105 uint8_t o1, o2;
106
107 if (!ptr)
108 break;
109
110 if (av_sscanf(ptr, "%c%c%c%c", &c1, &c2, &c3, &c4) != 4)
111 break;
112 o1 = convert(c2) | (convert(c1) << 4);
113 o2 = convert(c4) | (convert(c3) << 4);
114
115 lline = NULL;
116
117 if (i > 12 && o1 == 0x94 && o2 == 0x20 && saveptr &&
118 (av_strncasecmp(saveptr, "942f", 4) && !av_strncasecmp(saveptr, "942c", 4))) {
119
120 sub = ff_subtitles_queue_insert(&scc->q, out, i, 0);
121 if (!sub)
122 return AVERROR(ENOMEM);
123
124 sub->pos = pos;
125 pos += i;
126 sub->pts = ts;
127 sub->duration = i * 11;
128 ts += sub->duration;
129 i = 0;
130 }
131
132 out[i+0] = 0xfc;
133 out[i+1] = o1;
134 out[i+2] = o2;
135 }
136
137 sub = ff_subtitles_queue_insert(&scc->q, out, i, 0);
138 if (!sub)
139 return AVERROR(ENOMEM);
140
141 sub->pos = pos;
142 sub->pts = ts;
143 }
144
145 ff_subtitles_queue_finalize(s, &scc->q);
146
147 return 0;
148 }
149
150 const AVInputFormat ff_scc_demuxer = {
151 .name = "scc",
152 .long_name = NULL_IF_CONFIG_SMALL("Scenarist Closed Captions"),
153 .priv_data_size = sizeof(SCCContext),
154 .flags_internal = FF_FMT_INIT_CLEANUP,
155 .read_probe = scc_probe,
156 .read_header = scc_read_header,
157 .extensions = "scc",
158 .read_packet = ff_subtitles_read_packet,
159 .read_seek2 = ff_subtitles_read_seek,
160 .read_close = ff_subtitles_read_close,
161 };
162