Hi, Basically I'm Unity AR developer with C# as my background. So It's feeling like I'm driving a power packed Alien Ship without a user manual (Available APIs and Intellisense).
I have checked the AR-NFT-Video_Example.html file, I haven't seen any callback methods are listed on the file to handle the marker lost and found events (Maybe I'm wrong). So I have added my own lines for callbacks. It

You notice that the model or mesh (sphere) without the @hatsumatsu trick interpolating the tracking matrices is flickering/moving a lot. Why this happens? Because we should apply after the tracking a filter to remove the 'noise' with the arFilterTransMat It was 'planned' to add in t