I get a Screenshot of a Black Image in .png format.
Screenshots of video using Direct-To-Plane rendering is not implemented and will give you a black picture, screenshots using EGL renderer should work but Direct-To-Plane rendering is preferred for performance reasons.
It looks like you have a few plugins installed that may cause instability, plugin.video.youtube seems to complain about missing settings, there was some ALSA log entries I have never seen before.
I suggest you try with a single/minimal addon on a clean install using HDMI/SPDIF audio. One or more of the addons is probably causing exessive resource usage.