[popcornmix]

I just tested with 2 of my problematic 3D MVC mkv.
The result is just perfect with the sample I published, fluid and syncrhonized, as it is with OMXPlayer !!!!
Congratulations !!!!

I've been investigating. The cause was PR:8610. I suspect builds before then were better.
Minimising latency is good. But there is danger of hw decoder's input running dry and so it can sit there idle.
Increasing clock which was my suggestion which allows decoder to catch up.

It looks like we can also fix this by increasing the latency a little. It seems and extra two or three frames is enough, which should be fine.
I've pushed a test commit which should appear in tonight's build. Can you try removing the gpu_freq line in config.txt when you've updated to new build and see how it is?