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https://git.videolan.org/git/ffmpeg.git
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192 lines
5.5 KiB
C
192 lines
5.5 KiB
C
/*
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* 8088flex TMV file demuxer
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* Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* 8088flex TMV file demuxer
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* @file libavformat/tmv.c
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* @author Daniel Verkamp
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* @sa http://www.oldskool.org/pc/8088_Corruption
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*/
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#include "libavutil/intreadwrite.h"
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#include "avformat.h"
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enum {
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TMV_PADDING = 0x01,
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TMV_STEREO = 0x02,
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};
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#define TMV_TAG MKTAG('T', 'M', 'A', 'V')
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typedef struct TMVContext {
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unsigned audio_chunk_size;
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unsigned video_chunk_size;
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unsigned padding;
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unsigned stream_index;
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} TMVContext;
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#define TMV_HEADER_SIZE 12
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#define PROBE_MIN_SAMPLE_RATE 5000
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#define PROBE_MAX_FPS 120
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#define PROBE_MIN_AUDIO_SIZE (PROBE_MIN_SAMPLE_RATE / PROBE_MAX_FPS)
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static int tmv_probe(AVProbeData *p)
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{
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if (AV_RL32(p->buf) == TMV_TAG &&
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AV_RL16(p->buf+4) >= PROBE_MIN_SAMPLE_RATE &&
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AV_RL16(p->buf+6) >= PROBE_MIN_AUDIO_SIZE &&
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!p->buf[8] && // compression method
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p->buf[9] && // char cols
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p->buf[10]) // char rows
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return AVPROBE_SCORE_MAX /
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((p->buf[9] == 40 && p->buf[10] == 25) ? 1 : 4);
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return 0;
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}
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static int tmv_read_header(AVFormatContext *s, AVFormatParameters *ap)
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{
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TMVContext *tmv = s->priv_data;
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ByteIOContext *pb = s->pb;
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AVStream *vst, *ast;
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AVRational fps;
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unsigned comp_method, char_cols, char_rows, features;
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if (get_le32(pb) != TMV_TAG)
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return -1;
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if (!(vst = av_new_stream(s, 0)))
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return AVERROR(ENOMEM);
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if (!(ast = av_new_stream(s, 0)))
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return AVERROR(ENOMEM);
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ast->codec->sample_rate = get_le16(pb);
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if (!ast->codec->sample_rate) {
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av_log(s, AV_LOG_ERROR, "invalid sample rate\n");
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return -1;
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}
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tmv->audio_chunk_size = get_le16(pb);
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if (!tmv->audio_chunk_size) {
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av_log(s, AV_LOG_ERROR, "invalid audio chunk size\n");
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return -1;
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}
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comp_method = get_byte(pb);
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if (comp_method) {
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av_log(s, AV_LOG_ERROR, "unsupported compression method %d\n",
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comp_method);
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return -1;
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}
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char_cols = get_byte(pb);
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char_rows = get_byte(pb);
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tmv->video_chunk_size = char_cols * char_rows * 2;
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features = get_byte(pb);
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if (features & ~(TMV_PADDING | TMV_STEREO)) {
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av_log(s, AV_LOG_ERROR, "unsupported features 0x%02x\n",
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features & ~(TMV_PADDING | TMV_STEREO));
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return -1;
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}
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ast->codec->codec_type = CODEC_TYPE_AUDIO;
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ast->codec->codec_id = CODEC_ID_PCM_U8;
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ast->codec->channels = features & TMV_STEREO ? 2 : 1;
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ast->codec->bits_per_coded_sample = 8;
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ast->codec->bit_rate = ast->codec->sample_rate *
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ast->codec->bits_per_coded_sample;
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av_set_pts_info(ast, 32, 1, ast->codec->sample_rate);
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fps.num = ast->codec->sample_rate * ast->codec->channels;
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fps.den = tmv->audio_chunk_size;
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av_reduce(&fps.num, &fps.den, fps.num, fps.den, 0xFFFFFFFFLL);
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vst->codec->codec_type = CODEC_TYPE_VIDEO;
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vst->codec->codec_id = CODEC_ID_TMV;
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vst->codec->pix_fmt = PIX_FMT_PAL8;
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vst->codec->width = char_cols * 8;
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vst->codec->height = char_rows * 8;
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av_set_pts_info(vst, 32, fps.den, fps.num);
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if (features & TMV_PADDING)
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tmv->padding =
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((tmv->video_chunk_size + tmv->audio_chunk_size + 511) & ~511) -
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(tmv->video_chunk_size + tmv->audio_chunk_size);
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vst->codec->bit_rate = ((tmv->video_chunk_size + tmv->padding) *
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fps.num * 8) / fps.den;
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return 0;
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}
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static int tmv_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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TMVContext *tmv = s->priv_data;
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ByteIOContext *pb = s->pb;
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int ret, pkt_size = tmv->stream_index ?
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tmv->audio_chunk_size : tmv->video_chunk_size;
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if (url_feof(pb))
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return AVERROR_EOF;
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ret = av_get_packet(pb, pkt, pkt_size);
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if (tmv->stream_index)
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url_fskip(pb, tmv->padding);
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pkt->stream_index = tmv->stream_index;
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tmv->stream_index ^= 1;
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pkt->flags |= PKT_FLAG_KEY;
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return ret;
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}
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static int tmv_read_seek(AVFormatContext *s, int stream_index,
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int64_t timestamp, int flags)
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{
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TMVContext *tmv = s->priv_data;
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int64_t pos;
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if (stream_index)
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return -1;
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pos = timestamp *
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(tmv->audio_chunk_size + tmv->video_chunk_size + tmv->padding);
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url_fseek(s->pb, pos + TMV_HEADER_SIZE, SEEK_SET);
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tmv->stream_index = 0;
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return 0;
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}
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AVInputFormat tmv_demuxer = {
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"tmv",
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NULL_IF_CONFIG_SMALL("8088flex TMV"),
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sizeof(TMVContext),
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tmv_probe,
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tmv_read_header,
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tmv_read_packet,
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NULL,
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tmv_read_seek,
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.flags = AVFMT_GENERIC_INDEX,
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};
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