1 /*
2 * Tele-typewriter demuxer
3 * Copyright (c) 2010 Peter Ross <pross@xvid.org>
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 /**
23 * @file
24 * Tele-typewriter demuxer
25 */
26
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"
33 #include "avformat.h"
34 #include "internal.h"
35 #include "sauce.h"
36
37 typedef struct TtyDemuxContext {
38 AVClass *class;
39 int chars_per_frame;
40 uint64_t fsize; /**< file size less metadata buffer */
41 int width, height; /**< Set by a private option. */
42 AVRational framerate; /**< Set by a private option. */
43 } TtyDemuxContext;
44
45 /**
46 * Parse EFI header
47 */
efi_read(AVFormatContext * avctx,uint64_t start_pos)48 static int efi_read(AVFormatContext *avctx, uint64_t start_pos)
49 {
50 TtyDemuxContext *s = avctx->priv_data;
51 AVIOContext *pb = avctx->pb;
52 char buf[37];
53 int len;
54
55 avio_seek(pb, start_pos, SEEK_SET);
56 if (avio_r8(pb) != 0x1A)
57 return -1;
58
59 #define GET_EFI_META(name,size) \
60 len = avio_r8(pb); \
61 if (len < 1 || len > size) \
62 return -1; \
63 if (avio_read(pb, buf, size) == size) { \
64 buf[len] = 0; \
65 av_dict_set(&avctx->metadata, name, buf, 0); \
66 }
67
68 GET_EFI_META("filename", 12)
69 GET_EFI_META("title", 36)
70
71 s->fsize = start_pos;
72 return 0;
73 }
74
read_header(AVFormatContext * avctx)75 static int read_header(AVFormatContext *avctx)
76 {
77 TtyDemuxContext *s = avctx->priv_data;
78 int ret = 0;
79 AVStream *st = avformat_new_stream(avctx, NULL);
80
81 if (!st) {
82 ret = AVERROR(ENOMEM);
83 goto fail;
84 }
85 st->codecpar->codec_tag = 0;
86 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
87 st->codecpar->codec_id = AV_CODEC_ID_ANSI;
88
89 st->codecpar->width = s->width;
90 st->codecpar->height = s->height;
91 avpriv_set_pts_info(st, 60, s->framerate.den, s->framerate.num);
92 st->avg_frame_rate = s->framerate;
93
94 /* simulate tty display speed */
95 s->chars_per_frame = FFMAX(av_q2d(st->time_base)*s->chars_per_frame, 1);
96
97 if (avctx->pb->seekable & AVIO_SEEKABLE_NORMAL) {
98 s->fsize = avio_size(avctx->pb);
99 st->duration = (s->fsize + s->chars_per_frame - 1) / s->chars_per_frame;
100
101 if (ff_sauce_read(avctx, &s->fsize, 0, 0) < 0)
102 efi_read(avctx, s->fsize - 51);
103
104 avio_seek(avctx->pb, 0, SEEK_SET);
105 }
106
107 fail:
108 return ret;
109 }
110
read_packet(AVFormatContext * avctx,AVPacket * pkt)111 static int read_packet(AVFormatContext *avctx, AVPacket *pkt)
112 {
113 TtyDemuxContext *s = avctx->priv_data;
114 int n;
115
116 if (avio_feof(avctx->pb))
117 return AVERROR_EOF;
118
119 n = s->chars_per_frame;
120 if (s->fsize) {
121 // ignore metadata buffer
122 uint64_t p = avio_tell(avctx->pb);
123 if (p == s->fsize)
124 return AVERROR_EOF;
125 if (p + s->chars_per_frame > s->fsize)
126 n = s->fsize - p;
127 }
128
129 pkt->size = av_get_packet(avctx->pb, pkt, n);
130 if (pkt->size < 0)
131 return pkt->size;
132 pkt->flags |= AV_PKT_FLAG_KEY;
133 return 0;
134 }
135
136 #define OFFSET(x) offsetof(TtyDemuxContext, x)
137 #define DEC AV_OPT_FLAG_DECODING_PARAM
138 static const AVOption options[] = {
139 { "chars_per_frame", "", offsetof(TtyDemuxContext, chars_per_frame), AV_OPT_TYPE_INT, {.i64 = 6000}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM},
140 { "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
141 { "framerate", "", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, INT_MAX, DEC },
142 { NULL },
143 };
144
145 static const AVClass tty_demuxer_class = {
146 .class_name = "TTY demuxer",
147 .item_name = av_default_item_name,
148 .option = options,
149 .version = LIBAVUTIL_VERSION_INT,
150 };
151
152 AVInputFormat ff_tty_demuxer = {
153 .name = "tty",
154 .long_name = NULL_IF_CONFIG_SMALL("Tele-typewriter"),
155 .priv_data_size = sizeof(TtyDemuxContext),
156 .read_header = read_header,
157 .read_packet = read_packet,
158 .extensions = "ans,art,asc,diz,ice,nfo,txt,vt",
159 .priv_class = &tty_demuxer_class,
160 };
161