You guys can tell me to kick rocks as I’m assuming this is pretty niche, but I found an old stash of samples on an old hard drive (~10gb). They’re all in m4a format, but the S2400 cannot read the files. Of course I can do a quick script to convert all the files to .wav, but converting won’t increase audio quality (for obvious reason) and it will only substantially increase the file sizes.
Long way to say, will S2400 support M4A files at some point?
Sorry, there are no plans to support M4A files. The reason the S2400 uses WAV files is that they are uncompressed and can reliably be streamed from the SD card.
Thanks for the quick reply here Mickey!
M4A is just a container format, its basically MP4 aka MOV, inside this container there could be a variety of different audio codec formats, like AAC, MP3, PCM, ADPCM etc…
and MP4 is a horrible format to parse, I spent years of my life doing that and I am not going back 
What about Aiff- isnt that mostly just PCM WAV with different endian-ness?
Its an Apple file extension. Avoid as they will come looking for you for royalties 
I just use Perl and ffmpeg:
perl -MFile::Basename -le'for(<*.m4a>){$o=$_;$_=fileparse($_,".m4a");`ffmpeg -i "$o" -ac 2 -f wav "$_.wav"`}'
Yeah Perl is an option too, I just used a python package that converted the entire folder for me.