1/* 2 * CD Graphics Demuxer 3 * Copyright (c) 2009 Michael Tison 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22#include "avformat.h" 23#include "internal.h" 24 25#define CDG_PACKET_SIZE 24 26#define CDG_COMMAND 0x09 27#define CDG_MASK 0x3F 28 29static int read_header(AVFormatContext *s) 30{ 31 AVStream *vst; 32 int ret; 33 34 vst = avformat_new_stream(s, NULL); 35 if (!vst) 36 return AVERROR(ENOMEM); 37 38 vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO; 39 vst->codecpar->codec_id = AV_CODEC_ID_CDGRAPHICS; 40 41 /// 75 sectors/sec * 4 packets/sector = 300 packets/sec 42 avpriv_set_pts_info(vst, 32, 1, 300); 43 44 ret = avio_size(s->pb); 45 if (ret < 0) { 46 av_log(s, AV_LOG_WARNING, "Cannot calculate duration as file size cannot be determined\n"); 47 } else 48 vst->duration = (ret * (int64_t)vst->time_base.den) / (CDG_PACKET_SIZE * 300); 49 50 return 0; 51} 52 53static int read_packet(AVFormatContext *s, AVPacket *pkt) 54{ 55 int ret; 56 57 ret = av_get_packet(s->pb, pkt, CDG_PACKET_SIZE); 58 pkt->stream_index = 0; 59 pkt->dts= 60 pkt->pts= pkt->pos / CDG_PACKET_SIZE; 61 62 if (!pkt->pos || (ret > 5 && 63 (pkt->data[0] & CDG_MASK) == CDG_COMMAND && 64 (pkt->data[1] & CDG_MASK) == 1 && !(pkt->data[2+2+1] & 0x0F))) { 65 pkt->flags = AV_PKT_FLAG_KEY; 66 } 67 return ret; 68} 69 70const AVInputFormat ff_cdg_demuxer = { 71 .name = "cdg", 72 .long_name = NULL_IF_CONFIG_SMALL("CD Graphics"), 73 .read_header = read_header, 74 .read_packet = read_packet, 75 .flags = AVFMT_GENERIC_INDEX, 76 .extensions = "cdg", 77}; 78