I checked a few of them and seems that they are not quite fine tuned. The difference is from 5 cents to 50 cents. I do not know if my method of measurement is wrong or if the musicians do not play their instruments very carefully for recording.

I used Edison's Autodetect feature in FL Studio on Native Instruments Symphony libraries. Almost all of their samples have this problem.

 

yes the instruments are not meant to be flat precise. Thats one of the diffrences between real instruments and vsts. if you want them to be more precise you can always use an auto tune and blend the % of the correction to taste

 

But Native Instruments and other giants differ. Many people trust their sounds and don't doubt their correctness.

The way you said works for pop music well. In pop music, the number of notes is small and applying different effects is not a difficult task, but when the number of notes is large, the problem will be different. If the effect is to be applied to each note, most of the composer's time will be spent on unnecessary settings.

 

They don't doubt their sounds because they know its not meant to be perfectly tuned(to create a realistic emulation). With pianos, obviously they will be more accurately tuned(probably not fully though), but when you look at instruments like the flute, you expect it to be slightly off.

It doesn't matter if there are more number of notes. If the tuning is bothering you, all you gotta do is apply a pitch correction audio effect to the mixer and blend in the correction amount, like @Krugen mentioned. Its a global effect(for that mixer track), not different for each individual midi note.

If you still think the tuning is an issue, if you have the full kontakt vst, you can edit the patch and manually tune the samples to your liking. It will take a LOT of time and effort, depending on how big the library is, but if that's what you want, then so be it! XD