/* * CD Graphics Demuxer * Copyright (c) 2009 Michael Tison * * 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 */ #include "avformat.h"#include "demux.h"#include "internal.h" #define CDG_PACKET_SIZE    24#define CDG_COMMAND        0x09#define CDG_MASK           0x3F static int read_probe(const AVProbeData *p){    const int cnt = p->buf_size / CDG_PACKET_SIZE;    int score = 0;     for (int i = 0; i < cnt; i++) {        const int x = p->buf[i * CDG_PACKET_SIZE] & CDG_MASK;         score += x == CDG_COMMAND;        if (x != CDG_COMMAND && x != 0)            return 0;    }     return FFMIN(score, AVPROBE_SCORE_MAX);} static int read_header(AVFormatContext *s){    AVStream *vst;    int64_t ret;     vst = avformat_new_stream(s, NULL);    if (!vst)        return AVERROR(ENOMEM);     vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;    vst->codecpar->codec_id   = AV_CODEC_ID_CDGRAPHICS;     /// 75 sectors/sec * 4 packets/sector = 300 packets/sec    avpriv_set_pts_info(vst, 32, 1, 300);     ret = avio_size(s->pb);    if (ret < 0) {        av_log(s, AV_LOG_WARNING, "Cannot calculate duration as file size cannot be determined\n");    } else        vst->duration = (ret * (int64_t)vst->time_base.den) / (CDG_PACKET_SIZE * 300);     return 0;} static int read_packet(AVFormatContext *s, AVPacket *pkt){    int ret;     ret = av_get_packet(s->pb, pkt, CDG_PACKET_SIZE);    pkt->stream_index = 0;    pkt->dts=    pkt->pts= pkt->pos / CDG_PACKET_SIZE;     if (!pkt->pos || (ret > 5 &&         (pkt->data[0] & CDG_MASK) == CDG_COMMAND &&         (pkt->data[1] & CDG_MASK) == 1 && !(pkt->data[2+2+1] & 0x0F))) {        pkt->flags = AV_PKT_FLAG_KEY;    }    return ret;} const FFInputFormat ff_cdg_demuxer = {    .p.name         = "cdg",    .p.long_name    = NULL_IF_CONFIG_SMALL("CD Graphics"),    .p.flags        = AVFMT_GENERIC_INDEX,    .p.extensions   = "cdg",    .read_probe     = read_probe,    .read_header    = read_header,    .read_packet    = read_packet,};