As a quick pointer, if you get "unsupported format" for avi files, you might have to look into the FourCC codes. Sometimes, people code the video files (avi container with MPEG4 Part 2 ASP video and MP3 sound) with codec codes and description that are "funny" to the DSM-510, e.g. DX50. Google FourCC and find an editor. You might have to change the code and description in your video files to "XVID" to make it work on the DSM-510. To me, recoding is a ball of wax, and with the lossy nature of digital compression, can only lead to quality loss. Good luck.