Art Vista Virtual Grand Piano, and the following VGP2 were Kontakt Player instruments. When releasing VGP3 we left the Player platform, but remained in Kontakt. The Malmsjö had its own dongle-protected stand-alone player when it was released as a GVI instrument (GIGA Virtual Instrument.) Unfortunately Tascam discontinued GigaStudio, and further development and support of the GVI Player instruments stopped.
In "Malmsjö GVI for Kontakt" the GVI instrument has been re-sampled to include the effect of the proprietary DEF filters in the GVI. The DEF filters could be individually programmed for each velocity layer to gradually increase the harmonics and provide a smoother transition between layers, as well as increase the dynamic range. I think Tascam even showcased the filters by creating a piano complete with all dynamics out of a single sample layer.
The current Malmsjö GVI for Kontakt includes all previous incarnations of the Malmsjö, even the GigaStudio versions. The Tascam GVI dongle-protected standalone instrument is not included, but as described, it is re-sampled into a Kontakt instrument (sample).