Here's a test version for MKV support. No audio yet. Feedback will be appreciated. Use the same CUVID server and nvcuvid.dll as for 1.0.10. This version uses a revised DGA file format, so you'll have to remake your existing projects if you want to open them with this version.
http://neuron2.net/dgavcdecnv/dgavcdecnv1011test.zip
When reporting problems, please provide a stream sample that I can use to duplicate the issue.