1 /*
2 * SCC muxer
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 "libavutil/log.h"
25 #include "libavutil/intreadwrite.h"
26
27 typedef struct SCCContext {
28 int prev_h, prev_m, prev_s, prev_f;
29 int inside;
30 int n;
31 } SCCContext;
32
scc_write_header(AVFormatContext * avf)33 static int scc_write_header(AVFormatContext *avf)
34 {
35 SCCContext *scc = avf->priv_data;
36
37 if (avf->nb_streams != 1 ||
38 avf->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
39 av_log(avf, AV_LOG_ERROR,
40 "SCC supports only a single subtitles stream.\n");
41 return AVERROR(EINVAL);
42 }
43 if (avf->streams[0]->codecpar->codec_id != AV_CODEC_ID_EIA_608) {
44 av_log(avf, AV_LOG_ERROR,
45 "Unsupported subtitles codec: %s\n",
46 avcodec_get_name(avf->streams[0]->codecpar->codec_id));
47 return AVERROR(EINVAL);
48 }
49 avpriv_set_pts_info(avf->streams[0], 64, 1, 1000);
50 avio_printf(avf->pb, "Scenarist_SCC V1.0\n");
51
52 scc->prev_h = scc->prev_m = scc->prev_s = scc->prev_f = -1;
53 scc->inside = 0;
54
55 return 0;
56 }
57
scc_write_packet(AVFormatContext * avf,AVPacket * pkt)58 static int scc_write_packet(AVFormatContext *avf, AVPacket *pkt)
59 {
60 SCCContext *scc = avf->priv_data;
61 int64_t pts = pkt->pts;
62 int i, h, m, s, f;
63
64 if (pts == AV_NOPTS_VALUE) {
65 av_log(avf, AV_LOG_WARNING,
66 "Insufficient timestamps.\n");
67 return 0;
68 }
69
70 h = (int)(pts / (3600000));
71 m = (int)(pts / (60000)) % 60;
72 s = (int)(pts / 1000) % 60;
73 f = (int)(pts % 1000) / 33;
74
75 for (i = 0; i < pkt->size - 2; i+=3) {
76 if (pkt->data[i] == 0xfc && ((pkt->data[i + 1] != 0x80 || pkt->data[i + 2] != 0x80)))
77 break;
78 }
79 if (i >= pkt->size - 2)
80 return 0;
81
82 if (!scc->inside && (scc->prev_h != h || scc->prev_m != m || scc->prev_s != s || scc->prev_f != f)) {
83 avio_printf(avf->pb, "\n%02d:%02d:%02d:%02d\t", h, m, s, f);
84 scc->inside = 1;
85 }
86 for (i = 0; i < pkt->size; i+=3) {
87 if (i + 3 > pkt->size)
88 break;
89
90 if (pkt->data[i] != 0xfc || (pkt->data[i + 1] == 0x80 && pkt->data[i + 2] == 0x80))
91 continue;
92 if (!scc->inside) {
93 avio_printf(avf->pb, "\n%02d:%02d:%02d:%02d\t", h, m, s, f);
94 scc->inside = 1;
95 }
96 if (scc->n > 0)
97 avio_w8(avf->pb, ' ');
98 avio_printf(avf->pb, "%02x%02x", pkt->data[i + 1], pkt->data[i + 2]);
99 scc->n++;
100 }
101 if (scc->inside && (scc->prev_h != h || scc->prev_m != m || scc->prev_s != s || scc->prev_f != f)) {
102 avio_w8(avf->pb, '\n');
103 scc->n = 0;
104 scc->inside = 0;
105 }
106
107 scc->prev_h = h;
108 scc->prev_m = m;
109 scc->prev_s = s;
110 scc->prev_f = f;
111 return 0;
112 }
113
114 const AVOutputFormat ff_scc_muxer = {
115 .name = "scc",
116 .long_name = NULL_IF_CONFIG_SMALL("Scenarist Closed Captions"),
117 .extensions = "scc",
118 .priv_data_size = sizeof(SCCContext),
119 .write_header = scc_write_header,
120 .write_packet = scc_write_packet,
121 .flags = AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS | AVFMT_TS_NONSTRICT,
122 .subtitle_codec = AV_CODEC_ID_EIA_608,
123 };
124