From Hiroaki Matsumoto:
Nintendo DS Easy Music Transfer helps to transfer MP3, WMA, AAC(.m4a) music files to Nintendo DS. You can now transfer music using Nintendo DS Easy Music Transfer, if you cannot play the music properly, check (uncheck) "KDH mode" and try again. Nintendo DS Easy Music Transfer can convert and transfer multiple music files simultaneously to Nintendo DS. With Nintendo DS Easy Music Transfer, some MP4, FLV, MOV, AVI, WMV, MPG, and 3GP files can also be transferred with "Nintendo DS Easy Music Transfer." However, their video parts are not transferred. Only the music parts are transferred. - This software converts music files to AAC(.m4a)(sampling rate 44.1kHz, bitrate 128kbps). - "Windows Media Audio Lossless" files can not be converted. Please use "Windows Media Audio(128kbps)" instead.