Archos and rca lyra video player conversions

I am looking at getting an archos or rca audio/video player and am wondering about the video conversions to allow playback. “What you will playback is an AVI format file with MPEG4-SP VHS quality video and MP3 stereo sound.” what eactly does this mean and how easy/hard is it to put your movies on to here. assuming they are on a dvd. Is there any comments on this unit?