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141 lines
3.9 KiB
C
141 lines
3.9 KiB
C
/*
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* Copyright (C) 2008 Ramiro Polla
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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 "libavcodec/bytestream.h"
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#include "avformat.h"
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#define HEADER_SIZE 24
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/*
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* Header structure:
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* uint16_t ss; // struct size
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* uint16_t width; // frame width
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* uint16_t height; // frame height
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* uint16_t ff; // keyframe + some other info(???)
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* uint32_t size; // size of data
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* uint32_t fourcc; // ML20
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* uint32_t u3; // ?
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* uint32_t ts; // time
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*/
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static int msnwc_tcp_probe(AVProbeData *p)
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{
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int i;
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for(i = 0 ; i + HEADER_SIZE <= p->buf_size ; i++) {
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uint16_t width, height;
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uint32_t fourcc;
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const uint8_t *bytestream = p->buf+i;
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if(bytestream_get_le16(&bytestream) != HEADER_SIZE)
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continue;
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width = bytestream_get_le16(&bytestream);
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height = bytestream_get_le16(&bytestream);
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if(!(width==320 && height==240) && !(width==160 && height==120))
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continue;
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bytestream += 2; // keyframe
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bytestream += 4; // size
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fourcc = bytestream_get_le32(&bytestream);
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if(fourcc != MKTAG('M', 'L', '2', '0'))
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continue;
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if(i) {
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if(i < 14) /* starts with SwitchBoard connection info */
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return AVPROBE_SCORE_MAX / 2;
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else /* starts in the middle of stream */
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return AVPROBE_SCORE_MAX / 3;
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} else {
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return AVPROBE_SCORE_MAX;
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}
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}
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return -1;
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}
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static int msnwc_tcp_read_header(AVFormatContext *ctx, AVFormatParameters *ap)
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{
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AVIOContext *pb = ctx->pb;
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AVCodecContext *codec;
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AVStream *st;
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st = av_new_stream(ctx, 0);
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if(!st)
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return AVERROR(ENOMEM);
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codec = st->codec;
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codec->codec_type = AVMEDIA_TYPE_VIDEO;
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codec->codec_id = CODEC_ID_MIMIC;
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codec->codec_tag = MKTAG('M', 'L', '2', '0');
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av_set_pts_info(st, 32, 1, 1000);
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/* Some files start with "connected\r\n\r\n".
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* So skip until we find the first byte of struct size */
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while(avio_r8(pb) != HEADER_SIZE && !pb->eof_reached);
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if(pb->eof_reached) {
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av_log(ctx, AV_LOG_ERROR, "Could not find valid start.");
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return -1;
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}
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return 0;
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}
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static int msnwc_tcp_read_packet(AVFormatContext *ctx, AVPacket *pkt)
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{
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AVIOContext *pb = ctx->pb;
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uint16_t keyframe;
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uint32_t size, timestamp;
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avio_skip(pb, 1); /* one byte has been read ahead */
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avio_skip(pb, 2);
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avio_skip(pb, 2);
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keyframe = avio_rl16(pb);
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size = avio_rl32(pb);
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avio_skip(pb, 4);
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avio_skip(pb, 4);
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timestamp = avio_rl32(pb);
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if(!size || av_get_packet(pb, pkt, size) != size)
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return -1;
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avio_skip(pb, 1); /* Read ahead one byte of struct size like read_header */
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pkt->pts = timestamp;
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pkt->dts = timestamp;
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pkt->stream_index = 0;
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/* Some aMsn generated videos (or was it Mercury Messenger?) don't set
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* this bit and rely on the codec to get keyframe information */
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if(keyframe&1)
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pkt->flags |= AV_PKT_FLAG_KEY;
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return HEADER_SIZE + size;
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}
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AVInputFormat ff_msnwc_tcp_demuxer = {
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"msnwctcp",
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NULL_IF_CONFIG_SMALL("MSN TCP Webcam stream"),
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0,
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msnwc_tcp_probe,
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msnwc_tcp_read_header,
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msnwc_tcp_read_packet,
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};
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