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85 lines
2.2 KiB
C
85 lines
2.2 KiB
C
/*
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* CD Graphics Demuxer
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* Copyright (c) 2009 Michael Tison
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*
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* This file is part of Libav.
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*
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* Libav 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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* Libav 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 Libav; 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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#include "avformat.h"
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#include "internal.h"
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#define CDG_PACKET_SIZE 24
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#define CDG_COMMAND 0x09
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#define CDG_MASK 0x3F
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typedef struct CDGContext {
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int got_first_packet;
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} CDGContext;
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static int read_header(AVFormatContext *s)
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{
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AVStream *vst;
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int ret;
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vst = avformat_new_stream(s, NULL);
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if (!vst)
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return AVERROR(ENOMEM);
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vst->codec->codec_type = AVMEDIA_TYPE_VIDEO;
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vst->codec->codec_id = AV_CODEC_ID_CDGRAPHICS;
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/// 75 sectors/sec * 4 packets/sector = 300 packets/sec
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avpriv_set_pts_info(vst, 32, 1, 300);
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ret = avio_size(s->pb);
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if (ret < 0)
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return ret;
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vst->duration = (ret * vst->time_base.den) / (CDG_PACKET_SIZE * 300);
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return 0;
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}
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static int read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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CDGContext *priv = s->priv_data;
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int ret;
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while (1) {
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ret = av_get_packet(s->pb, pkt, CDG_PACKET_SIZE);
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if (ret < 1 || (pkt->data[0] & CDG_MASK) == CDG_COMMAND)
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break;
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av_free_packet(pkt);
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}
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if (!priv->got_first_packet) {
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pkt->flags |= AV_PKT_FLAG_KEY;
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priv->got_first_packet = 1;
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}
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pkt->stream_index = 0;
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return ret;
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}
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AVInputFormat ff_cdg_demuxer = {
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.name = "cdg",
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.long_name = NULL_IF_CONFIG_SMALL("CD Graphics"),
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.priv_data_size = sizeof(CDGContext),
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.read_header = read_header,
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.read_packet = read_packet,
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.extensions = "cdg",
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};
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