/*

  * Copyright (C) 2008  Ramiro Polla

  *
  * This file is part of FFmpeg.
  *
  * FFmpeg 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.
  *
  * FFmpeg 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 FFmpeg; 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"

 #include "internal.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)

 {

     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');
 

     avpriv_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 && !url_feof(pb));

 
     if(url_feof(pb)) {
         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,

 };