2 * Tele-typewriter demuxer
3 * Copyright (c) 2010 Peter Ross <pross@xvid.org>
5 * This file is part of FFmpeg.
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.
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.
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
24 * Tele-typewriter demuxer
27 #include "libavutil/intreadwrite.h"
28 #include "libavutil/avstring.h"
32 #define LINE_RATE 6000 /* characters per second */
36 uint64_t fsize; /**< file size less metadata buffer */
42 static int efi_read(AVFormatContext *avctx, uint64_t start_pos)
44 TtyDemuxContext *s = avctx->priv_data;
45 AVIOContext *pb = avctx->pb;
49 avio_seek(pb, start_pos, SEEK_SET);
50 if (avio_r8(pb) != 0x1A)
53 #define GET_EFI_META(name,size) \
55 if (len < 1 || len > size) \
57 if (avio_read(pb, buf, size) == size) { \
59 av_metadata_set2(&avctx->metadata, name, buf, 0); \
62 GET_EFI_META("filename", 12)
63 GET_EFI_META("title", 36)
69 static int read_header(AVFormatContext *avctx,
70 AVFormatParameters *ap)
72 TtyDemuxContext *s = avctx->priv_data;
73 AVStream *st = av_new_stream(avctx, 0);
75 return AVERROR(ENOMEM);
76 st->codec->codec_tag = 0;
77 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
78 st->codec->codec_id = CODEC_ID_ANSI;
79 if (ap->width) st->codec->width = ap->width;
80 if (ap->height) st->codec->height = ap->height;
82 if (!ap->time_base.num) {
83 av_set_pts_info(st, 60, 1, 25);
85 av_set_pts_info(st, 60, ap->time_base.num, ap->time_base.den);
88 /* simulate tty display speed */
89 s->chars_per_frame = FFMAX(av_q2d(st->time_base) * (ap->sample_rate ? ap->sample_rate : LINE_RATE), 1);
91 if (avctx->pb->seekable) {
92 s->fsize = avio_size(avctx->pb);
93 st->duration = (s->fsize + s->chars_per_frame - 1) / s->chars_per_frame;
95 if (ff_sauce_read(avctx, &s->fsize, 0, 0) < 0)
96 efi_read(avctx, s->fsize - 51);
98 avio_seek(avctx->pb, 0, SEEK_SET);
104 static int read_packet(AVFormatContext *avctx, AVPacket *pkt)
106 TtyDemuxContext *s = avctx->priv_data;
109 if (url_feof(avctx->pb))
112 n = s->chars_per_frame;
114 // ignore metadata buffer
115 uint64_t p = avio_tell(avctx->pb);
116 if (p + s->chars_per_frame > s->fsize)
120 pkt->size = av_get_packet(avctx->pb, pkt, n);
123 pkt->flags |= AV_PKT_FLAG_KEY;
127 AVInputFormat ff_tty_demuxer = {
129 .long_name = NULL_IF_CONFIG_SMALL("Tele-typewriter"),
130 .priv_data_size = sizeof(TtyDemuxContext),
131 .read_header = read_header,
132 .read_packet = read_packet,
133 .extensions = "ans,art,asc,diz,ice,nfo,txt,vt",