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/*
* Copyright (C) 2008 Ramiro Polla
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavcodec/bytestream.h"
#include "avformat.h"
#define HEADER_SIZE 24
/*
* Header structure:
* uint16_t ss; // struct size
* uint16_t width; // frame width
* uint16_t height; // frame height
* uint16_t ff; // keyframe + some other info(???)
* uint32_t size; // size of data
* uint32_t fourcc; // ML20
* uint32_t u3; // ?
* uint32_t ts; // time
*/
static int msnwc_tcp_probe(AVProbeData *p)
{
int i;
for(i = 0 ; i + HEADER_SIZE <= p->buf_size ; i++) {
uint16_t width, height;
uint32_t fourcc;
const uint8_t *bytestream = p->buf+i;
if(bytestream_get_le16(&bytestream) != HEADER_SIZE)
continue;
width = bytestream_get_le16(&bytestream);
height = bytestream_get_le16(&bytestream);
if(!(width==320 && height==240) && !(width==160 && height==120))
continue;
bytestream += 2; // keyframe
bytestream += 4; // size
fourcc = bytestream_get_le32(&bytestream);
if(fourcc != MKTAG('M', 'L', '2', '0'))
continue;
if(i) {
if(i < 14) /* starts with SwitchBoard connection info */
return AVPROBE_SCORE_MAX / 2;
else /* starts in the middle of stream */
return AVPROBE_SCORE_MAX / 3;
} else {
return AVPROBE_SCORE_MAX;
}
}
return -1;
}
static int msnwc_tcp_read_header(AVFormatContext *ctx, AVFormatParameters *ap)
{
AVIOContext *pb = ctx->pb;
AVCodecContext *codec;
AVStream *st;
st = avformat_new_stream(ctx, NULL);
if(!st)
return AVERROR(ENOMEM);
codec = st->codec;
codec->codec_type = AVMEDIA_TYPE_VIDEO;
codec->codec_id = CODEC_ID_MIMIC;
codec->codec_tag = MKTAG('M', 'L', '2', '0');
av_set_pts_info(st, 32, 1, 1000);
/* Some files start with "connected\r\n\r\n".
* So skip until we find the first byte of struct size */
while(avio_r8(pb) != HEADER_SIZE && !pb->eof_reached);
if(pb->eof_reached) {
av_log(ctx, AV_LOG_ERROR, "Could not find valid start.");
return -1;
}
return 0;
}
static int msnwc_tcp_read_packet(AVFormatContext *ctx, AVPacket *pkt)
{
AVIOContext *pb = ctx->pb;
uint16_t keyframe;
uint32_t size, timestamp;
avio_skip(pb, 1); /* one byte has been read ahead */
avio_skip(pb, 2);
avio_skip(pb, 2);
keyframe = avio_rl16(pb);
size = avio_rl32(pb);
avio_skip(pb, 4);
avio_skip(pb, 4);
timestamp = avio_rl32(pb);
if(!size || av_get_packet(pb, pkt, size) != size)
return -1;
avio_skip(pb, 1); /* Read ahead one byte of struct size like read_header */
pkt->pts = timestamp;
pkt->dts = timestamp;
pkt->stream_index = 0;
/* Some aMsn generated videos (or was it Mercury Messenger?) don't set
* this bit and rely on the codec to get keyframe information */
if(keyframe&1)
pkt->flags |= AV_PKT_FLAG_KEY;
return HEADER_SIZE + size;
}
AVInputFormat ff_msnwc_tcp_demuxer = {
.name = "msnwctcp",
.long_name = NULL_IF_CONFIG_SMALL("MSN TCP Webcam stream"),
.read_probe = msnwc_tcp_probe,
.read_header = msnwc_tcp_read_header,
.read_packet = msnwc_tcp_read_packet,
};
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