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/*
* 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 "avformat.h"
#include "sauce.h"
#define LINE_RATE 6000 /* characters per second */
typedef struct {
int chars_per_frame;
uint64_t fsize; /**< file size less metadata buffer */
} TtyDemuxContext;
/**
* 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;
url_fseek(pb, start_pos, SEEK_SET);
if (get_byte(pb) != 0x1A)
return -1;
#define GET_EFI_META(name,size) \
len = get_byte(pb); \
if (len < 1 || len > size) \
return -1; \
if (get_buffer(pb, buf, size) == size) { \
buf[len] = 0; \
av_metadata_set2(&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,
AVFormatParameters *ap)
{
TtyDemuxContext *s = avctx->priv_data;
AVStream *st = av_new_stream(avctx, 0);
if (!st)
return AVERROR(ENOMEM);
st->codec->codec_tag = 0;
st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
st->codec->codec_id = CODEC_ID_ANSI;
if (ap->width) st->codec->width = ap->width;
if (ap->height) st->codec->height = ap->height;
if (!ap->time_base.num) {
av_set_pts_info(st, 60, 1, 25);
} else {
av_set_pts_info(st, 60, ap->time_base.num, ap->time_base.den);
}
/* simulate tty display speed */
s->chars_per_frame = FFMAX(av_q2d(st->time_base) * (ap->sample_rate ? ap->sample_rate : LINE_RATE), 1);
if (!url_is_streamed(avctx->pb)) {
s->fsize = url_fsize(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);
url_fseek(avctx->pb, 0, SEEK_SET);
}
return 0;
}
static int read_packet(AVFormatContext *avctx, AVPacket *pkt)
{
TtyDemuxContext *s = avctx->priv_data;
int n;
if (url_feof(avctx->pb))
return AVERROR_EOF;
n = s->chars_per_frame;
if (s->fsize) {
// ignore metadata buffer
uint64_t p = url_ftell(avctx->pb);
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 AVERROR(EIO);
pkt->flags |= AV_PKT_FLAG_KEY;
return 0;
}
AVInputFormat ff_tty_demuxer = {
.name = "tty",
.long_name = NULL_IF_CONFIG_SMALL("Tele-typewriter"),
.priv_data_size = sizeof(TtyDemuxContext),
.read_header = read_header,
.read_packet = read_packet,
.extensions = "ans,art,asc,diz,ice,nfo,txt,vt",
};
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