This is not yet possible in the Master branch.
We’re having the code for this in a separate branch and are still working on cleaning it up. The implementation of the GDC version was put together rather quickly and is built on top of the existing Media Framework. We’re building a whole new version of the Media Framework to support this use case more generally and with better performance. Media Framework 3.0 is currently scheduled for 4.17, but that code, too, is still in a separate branch.