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/*
* 8088flex TMV file demuxer
* Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
*
* 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
*/
/**
* 8088flex TMV file demuxer
* @file
* @author Daniel Verkamp
* @sa http://www.oldskool.org/pc/8088_Corruption
*/
#include "libavutil/intreadwrite.h"
#include "avformat.h"
enum {
TMV_PADDING = 0x01,
TMV_STEREO = 0x02,
};
#define TMV_TAG MKTAG('T', 'M', 'A', 'V')
typedef struct TMVContext {
unsigned audio_chunk_size;
unsigned video_chunk_size;
unsigned padding;
unsigned stream_index;
} TMVContext;
#define TMV_HEADER_SIZE 12
#define PROBE_MIN_SAMPLE_RATE 5000
#define PROBE_MAX_FPS 120
#define PROBE_MIN_AUDIO_SIZE (PROBE_MIN_SAMPLE_RATE / PROBE_MAX_FPS)
static int tmv_probe(AVProbeData *p)
{
if (AV_RL32(p->buf) == TMV_TAG &&
AV_RL16(p->buf+4) >= PROBE_MIN_SAMPLE_RATE &&
AV_RL16(p->buf+6) >= PROBE_MIN_AUDIO_SIZE &&
!p->buf[8] && // compression method
p->buf[9] && // char cols
p->buf[10]) // char rows
return AVPROBE_SCORE_MAX /
((p->buf[9] == 40 && p->buf[10] == 25) ? 1 : 4);
return 0;
}
static int tmv_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
TMVContext *tmv = s->priv_data;
ByteIOContext *pb = s->pb;
AVStream *vst, *ast;
AVRational fps;
unsigned comp_method, char_cols, char_rows, features;
if (get_le32(pb) != TMV_TAG)
return -1;
if (!(vst = av_new_stream(s, 0)))
return AVERROR(ENOMEM);
if (!(ast = av_new_stream(s, 0)))
return AVERROR(ENOMEM);
ast->codec->sample_rate = get_le16(pb);
if (!ast->codec->sample_rate) {
av_log(s, AV_LOG_ERROR, "invalid sample rate\n");
return -1;
}
tmv->audio_chunk_size = get_le16(pb);
if (!tmv->audio_chunk_size) {
av_log(s, AV_LOG_ERROR, "invalid audio chunk size\n");
return -1;
}
comp_method = get_byte(pb);
if (comp_method) {
av_log(s, AV_LOG_ERROR, "unsupported compression method %d\n",
comp_method);
return -1;
}
char_cols = get_byte(pb);
char_rows = get_byte(pb);
tmv->video_chunk_size = char_cols * char_rows * 2;
features = get_byte(pb);
if (features & ~(TMV_PADDING | TMV_STEREO)) {
av_log(s, AV_LOG_ERROR, "unsupported features 0x%02x\n",
features & ~(TMV_PADDING | TMV_STEREO));
return -1;
}
ast->codec->codec_type = AVMEDIA_TYPE_AUDIO;
ast->codec->codec_id = CODEC_ID_PCM_U8;
ast->codec->channels = features & TMV_STEREO ? 2 : 1;
ast->codec->bits_per_coded_sample = 8;
ast->codec->bit_rate = ast->codec->sample_rate *
ast->codec->bits_per_coded_sample;
av_set_pts_info(ast, 32, 1, ast->codec->sample_rate);
fps.num = ast->codec->sample_rate * ast->codec->channels;
fps.den = tmv->audio_chunk_size;
av_reduce(&fps.num, &fps.den, fps.num, fps.den, 0xFFFFFFFFLL);
vst->codec->codec_type = AVMEDIA_TYPE_VIDEO;
vst->codec->codec_id = CODEC_ID_TMV;
vst->codec->pix_fmt = PIX_FMT_PAL8;
vst->codec->width = char_cols * 8;
vst->codec->height = char_rows * 8;
av_set_pts_info(vst, 32, fps.den, fps.num);
if (features & TMV_PADDING)
tmv->padding =
((tmv->video_chunk_size + tmv->audio_chunk_size + 511) & ~511) -
(tmv->video_chunk_size + tmv->audio_chunk_size);
vst->codec->bit_rate = ((tmv->video_chunk_size + tmv->padding) *
fps.num * 8) / fps.den;
return 0;
}
static int tmv_read_packet(AVFormatContext *s, AVPacket *pkt)
{
TMVContext *tmv = s->priv_data;
ByteIOContext *pb = s->pb;
int ret, pkt_size = tmv->stream_index ?
tmv->audio_chunk_size : tmv->video_chunk_size;
if (url_feof(pb))
return AVERROR_EOF;
ret = av_get_packet(pb, pkt, pkt_size);
if (tmv->stream_index)
url_fskip(pb, tmv->padding);
pkt->stream_index = tmv->stream_index;
tmv->stream_index ^= 1;
pkt->flags |= AV_PKT_FLAG_KEY;
return ret;
}
static int tmv_read_seek(AVFormatContext *s, int stream_index,
int64_t timestamp, int flags)
{
TMVContext *tmv = s->priv_data;
int64_t pos;
if (stream_index)
return -1;
pos = timestamp *
(tmv->audio_chunk_size + tmv->video_chunk_size + tmv->padding);
url_fseek(s->pb, pos + TMV_HEADER_SIZE, SEEK_SET);
tmv->stream_index = 0;
return 0;
}
AVInputFormat tmv_demuxer = {
"tmv",
NULL_IF_CONFIG_SMALL("8088flex TMV"),
sizeof(TMVContext),
tmv_probe,
tmv_read_header,
tmv_read_packet,
NULL,
tmv_read_seek,
.flags = AVFMT_GENERIC_INDEX,
};
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