Why does Synthesia read files so differently than other Music Notation Software?

[TristanSynth]

The other day, I transcribed an Irish tune into Musescore, arranged for piano. Musescore played the file cleanly and sounded even more impressive after installing a new soundfont. But when I exported the same file into Synthesia, and installed the same soundfont, Synthesia seemed to have some trouble playing it back. As if the play speed or framerate was inconsistent or something. I could tell the difference, and it was disappointing how apparent this difference was. Also, why do my other Music Notation Software programs(Musescore and Finale) translate all of my MIDI files into sheet music just fine, but Synthesia doesn't seem to know how to translate any of my MIDI files into sheet music?

[Nicholas]

As if the play speed or framerate was inconsistent or something.

Do you mean there were small variations in the timing of when the notes were played? Or was there something else different wrong with the sound?

Synthesia doesn't seem to know how to translate any of my MIDI files into sheet music?

Sorry, this should be getting better soon. (See the first bullet point.)

[Benjy52]

Synthesia uses only .sf2 files to export MIDI. Musescore, Finale and all of the others use a much less outdated format called a .sfz file. You need to make sure the sound file you use is an .sf2 file instead. Not as good quality but will fix the problem

[Nicholas]

My understanding is that SFZ can only support a single-instrument per file. Synthesia needs "GM" sound fonts with 127 instruments.