Chances are you are not creating a DVD-compatible disk. If you are simply taking video data files, encoded in formats such as avi, mpg, or mov, and copying them to a DVD as data files, they cannot be played back on a DVD player. A DVD disk uses a very specific format, in much the same way that a Red Book audio CD uses a very specific data structure and data storage format. A DVD contains an video layer, usually encoded in MPEG-2 format, at least one audio layer, encoded in PCM and/or Dolby Digital format, and a menu system. Other audio formats, such as DTS, are supported on many players, but are not part of the DVD standard. You need to use software that is designed to create DVD-playable disks. You will usually need to create a menu structure and tell the software what video and/or audio source files are required. The software will then render the data files you have specified into the appropriate format, after which they are used to burn the DVD. Rendering is a time-consuming process and the computer may require one or two minutes to create every minute of output. There are several inexpensive NLE (non-linear editing) programs on the market which can be used for this task, such as Pinnacle Studio and Adobe Premier Elements. Both of these sell for around US$100.