How do I write animation video files in VP9 (libvpx) codec format using vtk ?

I was successful in saving animation video using classes vtkAVIWriter and vtkFFMPEGWriter with different codec formats, but I would prefer saving videos in VP9 codec format (libvpx) which is completely royalty free. Has anyone tried to create a custom Writer class for VP9?

We implemented VTK classes for VP9 encoding/decoding and storage of images + text metadata in MKV container in IGSIO library. There are a couple of tests/examples in the repository and the library is used in 3D Slicer and Plus toolkit for record/replay/stream compressed video. If you have any questions about how to use the library then you can post them as issues in the IGSIO repository.

How does the mkv container differ from vtkAVIWriter or vtkFFMPEFWriter it doesn’t seem to implement vtkGenericMovieWriter?

We don’t use vtkGenericMovieWriter interface, as it would be too way too limited for our use cases. Instead, we store input image sequence in vtkIGSIOTrackedFrameList, which allows random read/write access of compressed and uncompressed frames, arbitrarily varying frame rate, per-frame metadata, managing of missing frames, etc.