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101 lines
2.6 KiB
C
101 lines
2.6 KiB
C
/*
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* NC camera feed demuxer
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* Copyright (c) 2009 Nicolas Martin (martinic at iro dot umontreal dot ca)
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* Edouard Auvinet
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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 "libavutil/intreadwrite.h"
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#include "avformat.h"
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#define NC_VIDEO_FLAG 0x1A5
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static int nc_probe(AVProbeData *probe_packet)
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{
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int size;
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if (AV_RB32(probe_packet->buf) != NC_VIDEO_FLAG)
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return 0;
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size = AV_RL16(probe_packet->buf + 5);
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if (size + 20 > probe_packet->buf_size)
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return AVPROBE_SCORE_MAX/4;
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if (AV_RB32(probe_packet->buf+16+size) == NC_VIDEO_FLAG)
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return AVPROBE_SCORE_MAX;
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return 0;
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}
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static int nc_read_header(AVFormatContext *s, AVFormatParameters *ap)
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{
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AVStream *st = av_new_stream(s, 0);
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if (!st)
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return AVERROR(ENOMEM);
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st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
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st->codec->codec_id = CODEC_ID_MPEG4;
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st->need_parsing = AVSTREAM_PARSE_FULL;
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av_set_pts_info(st, 64, 1, 100);
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return 0;
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}
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static int nc_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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int size;
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int ret;
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uint32_t state=-1;
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while (state != NC_VIDEO_FLAG) {
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if (s->pb->eof_reached)
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return AVERROR(EIO);
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state = (state<<8) + avio_r8(s->pb);
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}
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avio_r8(s->pb);
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size = avio_rl16(s->pb);
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avio_skip(s->pb, 9);
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if (size == 0) {
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av_log(s, AV_LOG_DEBUG, "Next packet size is zero\n");
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return AVERROR(EAGAIN);
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}
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ret = av_get_packet(s->pb, pkt, size);
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if (ret != size) {
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if (ret > 0) av_free_packet(pkt);
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return AVERROR(EIO);
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}
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pkt->stream_index = 0;
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return size;
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}
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AVInputFormat ff_nc_demuxer = {
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.name = "nc",
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.long_name = NULL_IF_CONFIG_SMALL("NC camera feed format"),
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.read_probe = nc_probe,
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.read_header = nc_read_header,
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.read_packet = nc_read_packet,
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.extensions = "v",
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};
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