Jeeb’s patch to add the high bitdepth y4m formats has now made its way into x264. This means that you can now use y4m for 10 bit input too and save the trouble of manually specifying the input properties.
VapourSynth
The future home of VapourSynth… 3000!
Add audio.
There is a thing called x264-audio, made by Kovensky.
https://github.com/Kovensky/x264-audio