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
37typedef 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 */
48static 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
75static 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
107fail:
108    return ret;
109}
110
111static int read_packet(AVFormatContext *avctx, AVPacket *pkt)
112{
113    TtyDemuxContext *s = avctx->priv_data;
114    int n;
115
116    if (url_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
138static 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
145static 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
152AVInputFormat 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