Avi is a media container format which can be encoded with many different codecs, such as divx, xvid, mpeg4, mjpeg, etc, so no dvd player can play all avi files, and I think your dvd player can't recognize MPEG4 avi file, I don't know the exact brand and model of your dvd player, so can't give your the exact answer, but if a dvd player can play some avi files, usually can play divx or xvid avi files well, one of them should be right for your dvd player, so you can follow me to use RZ DVD Creator to help you, it can directly convert any video files to Divx or Xvid avi files, such as convert your MKV video files to Divx or Xvid avi files to play well on your DVD player, easy to use, run RZ DVD Creator, directly drag and drop your MKV video files into RZ DVD Creator, then select "divx-dvd" or "xvid-dvd" as target format, at last press START button, the software will convert your MKV video files to divx or xvid avi files, then you can play the converted avi files well on your DVD player. You can yahoo or google search and download RZ DVD Creator, easy to use, hope it can help you.