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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 { | |
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 | */ | |
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 | ||
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->codec->codec_tag = 0; | |
86 | st->codec->codec_type = AVMEDIA_TYPE_VIDEO; | |
87 | st->codec->codec_id = AV_CODEC_ID_ANSI; | |
88 | ||
89 | st->codec->width = s->width; | |
90 | st->codec->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) { | |
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 | ||
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, 0, 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 | }; |