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"
29 #include "libavutil/log.h"
30 #include "libavutil/dict.h"
31 #include "libavutil/opt.h"
32 #include "libavutil/parseutils.h"
37 static int isansicode(int x)
39 return x == 0x1B || x == 0x0A || x == 0x0D || (x >= 0x20 && x < 0x7f);
42 static const char tty_extensions[31] = "ans,art,asc,diz,ice,nfo,txt,vt";
44 typedef struct TtyDemuxContext {
47 uint64_t fsize; /**< file size less metadata buffer */
48 int width, height; /**< Set by a private option. */
49 AVRational framerate; /**< Set by a private option. */
52 static int read_probe(const AVProbeData *p)
59 for (int i = 0; i < p->buf_size; i++)
60 cnt += !!isansicode(p->buf[i]);
62 return (cnt * 100LL / p->buf_size) * (cnt > 400) *
63 !!av_match_ext(p->filename, tty_extensions);
69 static int efi_read(AVFormatContext *avctx, uint64_t start_pos)
71 TtyDemuxContext *s = avctx->priv_data;
72 AVIOContext *pb = avctx->pb;
76 avio_seek(pb, start_pos, SEEK_SET);
77 if (avio_r8(pb) != 0x1A)
80 #define GET_EFI_META(name,size) \
82 if (len < 1 || len > size) \
84 if (avio_read(pb, buf, size) == size) { \
86 av_dict_set(&avctx->metadata, name, buf, 0); \
89 GET_EFI_META("filename", 12)
90 GET_EFI_META("title", 36)
96 static int read_header(AVFormatContext *avctx)
98 TtyDemuxContext *s = avctx->priv_data;
100 AVStream *st = avformat_new_stream(avctx, NULL);
103 ret = AVERROR(ENOMEM);
106 st->codecpar->codec_tag = 0;
107 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
108 st->codecpar->codec_id = AV_CODEC_ID_ANSI;
110 st->codecpar->width = s->width;
111 st->codecpar->height = s->height;
112 avpriv_set_pts_info(st, 60, s->framerate.den, s->framerate.num);
113 st->avg_frame_rate = s->framerate;
115 /* simulate tty display speed */
116 s->chars_per_frame = FFMAX(av_q2d(st->time_base)*s->chars_per_frame, 1);
118 if (avctx->pb->seekable & AVIO_SEEKABLE_NORMAL) {
119 s->fsize = avio_size(avctx->pb);
120 st->duration = (s->fsize + s->chars_per_frame - 1) / s->chars_per_frame;
122 if (ff_sauce_read(avctx, &s->fsize, 0, 0) < 0)
123 efi_read(avctx, s->fsize - 51);
125 avio_seek(avctx->pb, 0, SEEK_SET);
132 static int read_packet(AVFormatContext *avctx, AVPacket *pkt)
134 TtyDemuxContext *s = avctx->priv_data;
137 if (avio_feof(avctx->pb))
140 n = s->chars_per_frame;
142 // ignore metadata buffer
143 uint64_t p = avio_tell(avctx->pb);
146 if (p + s->chars_per_frame > s->fsize)
150 pkt->size = av_get_packet(avctx->pb, pkt, n);
153 pkt->flags |= AV_PKT_FLAG_KEY;
157 #define OFFSET(x) offsetof(TtyDemuxContext, x)
158 #define DEC AV_OPT_FLAG_DECODING_PARAM
159 static const AVOption options[] = {
160 { "chars_per_frame", "", offsetof(TtyDemuxContext, chars_per_frame), AV_OPT_TYPE_INT, {.i64 = 6000}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM},
161 { "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
162 { "framerate", "", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, INT_MAX, DEC },
166 static const AVClass tty_demuxer_class = {
167 .class_name = "TTY demuxer",
168 .item_name = av_default_item_name,
170 .version = LIBAVUTIL_VERSION_INT,
173 AVInputFormat ff_tty_demuxer = {
175 .long_name = NULL_IF_CONFIG_SMALL("Tele-typewriter"),
176 .priv_data_size = sizeof(TtyDemuxContext),
177 .read_probe = read_probe,
178 .read_header = read_header,
179 .read_packet = read_packet,
180 .extensions = tty_extensions,
181 .priv_class = &tty_demuxer_class,