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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 "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;
if (!p->buf_size)
return 0;
for (int i = 0; i < 8 && i < p->buf_size; i++)
cnt += !!isansicode(p->buf[i]);
if (cnt != 8)
return 0;
for (int i = 8; 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->stream_index = 0;
pkt->pts = pkt->pos / n;
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,
.flags = AVFMT_GENERIC_INDEX,
};
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