what determines if a song is acceptable with no copyright issues?

[Izlude77714]

is it possible to use songs that are from deceased artists?

for example there are versions of fotbb/winter wind etude ingame
what made those specific versions usable?

as an example
could cziffra's version of flight of the bumblee or winter wind be used?

it would be sweet to get classical pieces put ingame that were performed by legendary virtuoso pianists instead of our generic versions that are being used whenever someone steps classical music