1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
|
/*
* Tele-typewriter demuxer
* Copyright (c) 2010 Peter Ross <pross@xvid.org>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Tele-typewriter demuxer
*/
#include "libavutil/intreadwrite.h"
#include "libavutil/avstring.h"
#include "libavutil/log.h"
#include "libavutil/dict.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "avformat.h"
#include "internal.h"
#include "sauce.h"
static int isansicode(int x)
{
return x == 0x1B || x == 0x0A || x == 0x0D || (x >= 0x20 && x < 0x7f);
}
static const char tty_extensions[31] = "ans,art,asc,diz,ice,nfo,txt,vt";
typedef struct TtyDemuxContext {
AVClass *class;
int chars_per_frame;
uint64_t fsize; /**< file size less metadata buffer */
int width, height; /**< Set by a private option. */
AVRational framerate; /**< Set by a private option. */
} TtyDemuxContext;
static int read_probe(const AVProbeData *p)
{
int cnt = 0;
for (int i = 0; i < p->buf_size; i++)
cnt += !!isansicode(p->buf[i]);
return (cnt * 100LL / p->buf_size) * (cnt > 400) *
!!av_match_ext(p->filename, tty_extensions);
}
/**
* Parse EFI header
*/
static int efi_read(AVFormatContext *avctx, uint64_t start_pos)
{
TtyDemuxContext *s = avctx->priv_data;
AVIOContext *pb = avctx->pb;
char buf[37];
int len;
avio_seek(pb, start_pos, SEEK_SET);
if (avio_r8(pb) != 0x1A)
return -1;
#define GET_EFI_META(name,size) \
len = avio_r8(pb); \
if (len < 1 || len > size) \
return -1; \
if (avio_read(pb, buf, size) == size) { \
buf[len] = 0; \
av_dict_set(&avctx->metadata, name, buf, 0); \
}
GET_EFI_META("filename", 12)
GET_EFI_META("title", 36)
s->fsize = start_pos;
return 0;
}
static int read_header(AVFormatContext *avctx)
{
TtyDemuxContext *s = avctx->priv_data;
int ret = 0;
AVStream *st = avformat_new_stream(avctx, NULL);
if (!st) {
ret = AVERROR(ENOMEM);
goto fail;
}
st->codecpar->codec_tag = 0;
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_ANSI;
st->codecpar->width = s->width;
st->codecpar->height = s->height;
avpriv_set_pts_info(st, 60, s->framerate.den, s->framerate.num);
st->avg_frame_rate = s->framerate;
/* simulate tty display speed */
s->chars_per_frame = FFMAX(av_q2d(st->time_base)*s->chars_per_frame, 1);
if (avctx->pb->seekable & AVIO_SEEKABLE_NORMAL) {
s->fsize = avio_size(avctx->pb);
st->duration = (s->fsize + s->chars_per_frame - 1) / s->chars_per_frame;
if (ff_sauce_read(avctx, &s->fsize, 0, 0) < 0)
efi_read(avctx, s->fsize - 51);
avio_seek(avctx->pb, 0, SEEK_SET);
}
fail:
return ret;
}
static int read_packet(AVFormatContext *avctx, AVPacket *pkt)
{
TtyDemuxContext *s = avctx->priv_data;
int n;
if (avio_feof(avctx->pb))
return AVERROR_EOF;
n = s->chars_per_frame;
if (s->fsize) {
// ignore metadata buffer
uint64_t p = avio_tell(avctx->pb);
if (p == s->fsize)
return AVERROR_EOF;
if (p + s->chars_per_frame > s->fsize)
n = s->fsize - p;
}
pkt->size = av_get_packet(avctx->pb, pkt, n);
if (pkt->size < 0)
return pkt->size;
pkt->flags |= AV_PKT_FLAG_KEY;
return 0;
}
#define OFFSET(x) offsetof(TtyDemuxContext, x)
#define DEC AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
{ "chars_per_frame", "", offsetof(TtyDemuxContext, chars_per_frame), AV_OPT_TYPE_INT, {.i64 = 6000}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM},
{ "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
{ "framerate", "", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, INT_MAX, DEC },
{ NULL },
};
static const AVClass tty_demuxer_class = {
.class_name = "TTY demuxer",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
AVInputFormat ff_tty_demuxer = {
.name = "tty",
.long_name = NULL_IF_CONFIG_SMALL("Tele-typewriter"),
.priv_data_size = sizeof(TtyDemuxContext),
.read_probe = read_probe,
.read_header = read_header,
.read_packet = read_packet,
.extensions = tty_extensions,
.priv_class = &tty_demuxer_class,
};
|
