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92 lines
2.6 KiB
92 lines
2.6 KiB
/* |
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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 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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#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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av_log(s, AV_LOG_WARNING, "Cannot calculate duration as file size cannot be determined\n"); |
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} else |
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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_packet_unref(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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pkt->dts= |
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pkt->pts= pkt->pos / CDG_PACKET_SIZE; |
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if(ret>5 && (pkt->data[0]&0x3F) == 9 && (pkt->data[1]&0x3F)==1 && !(pkt->data[2+2+1] & 0x0F)){ |
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pkt->flags = AV_PKT_FLAG_KEY; |
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} |
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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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.flags = AVFMT_GENERIC_INDEX, |
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.extensions = "cdg", |
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};
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