VLC/Xine/Mplayer choppy HEVC / H.265 playback

Hi all. I do not know if it is my first HEVC video file ever, but I am not able to smoothly playback my file. On each player (VLC/Xine/Mplayer), the playback is very choppy and the debug output indicates that frames are being dropped. Given that all players are affected, it was wondering if a) something was wrong with my multimedia libs (TW, VLC repo and Packman repo for the rest) or b) my computer has become too old to play H265 (Lenovo SL500: Dual core 1.66 GHz, 6GB RAM, Intel graphics GMA 4500M).

How can we best diagnose the issue?

In any case you should not use both the VLC and the Packman repo. Stick to Packman. But I do not know if that is causing your problem.

Unfortunately, I have to use the official VLC repo because the Packman packages are affected by a Qt bug at the moment (see this). I know that this situation is not ideal and I will test-wise deactivate the VLC repo to check the consistency with Packman-only multimedia libs.

Be sure you don’t use mixed package all from one or the other

As this is a bug in Qt5.5, it should affect the version from the official VLC repo as well.
But it is fixed already anyway.

Also, try to uninstall libvdpau_va_gl1. VLC should then fallback to native VA-API acceleration.
With that package installed, it will use VDPAU, which is then re-routed to VA-API by that package, and maybe there’s some problem with that (like insufficient H.265 support).