Have 4 channel DVR with h.264 compresssion and default encoding was D1. Watch playback on DVR monitor is fine. After I made backup copy on USB drive to give to police. I tried to open the files and the show to have .dat ext and Ive tried every codec player/converter but still no luck. Went ahead and changed hard drive in DVR and set to CIF. How do i view files from the original drive