Now you can convert any of your audio/video files to M4A format easily. M4A Converter supports MP3, WAV, AAC, WMA, FLAC, M4A and AC3. It can also convert video to audio, it supports WMV, MP4, 3GP, MKV, FLV, VOB, MPG, AVI, MOV etc.
You can set the BitRate of the output audio.