there is a free sampler plugin DecentSampler which is closed source, but there is at least a x86_64 Linux build. I reckon it was mostly developed as a propirietary platform to sell sample packages.
But a lot of the free sample packages at PianoBook are published in this format (at least a lot more then SFZs), so I wondered if it would be worth to ask the developer for a ARM build (if this is even possible) to include it as an engine in Zynthian.
Would it be a valuable addition to Zynthian and worth the effort?
Sfizz has an import function for Decent files, I haven’t tried it, but theoretically it could already work.
Another possibility would be to convert the Decent files to SFZ or SF2 with ConvertWithMoss.
The point of some open source projects (also) hosting closed proprietary formats, like MuseSounds on Musescore, is to raise some money to support the maintenance and development of the main free enterprise. Therefore, I deem it quite unlikely that the DS development team has any interest in making the format of some of their paid proprietary content easily available to other free, non proprietary and unpaid platforms. This obviously doesn’t rule out the possibility of conversion to sfz through some toilsome intermediate procedure, but it is up to the user to decide whether the quality of the library is worth embarking in the trouble of the job, most of the times ending up with an instrument which is not exactly as polished and functional as originally meant.