VAAPI

VAAPI (Video Acceleration API) provides access to graphics hardware (GPU) acceleration for video processing.

Installation
VAAPI support can be enabled system-wide by adding the  value to the USE variable:

Enabling VAAPI support will pull in the package, which has the following USE flags:

The system needs to be updated if the USE variable was set to :

Usage
Run to check VAAPI support.

VLC
VLC supports VAAPI natively. Activate the appropriate setting through the preferences menu (Tools->Preferences->Input/Codecs->Hardware accelerated decoding).

mpv
mpv also supports the VAAPI acceleration through the command line option.

MPlayer
Currently, the main MPlayer branch doesn't support VAAPI. There is a development branch (hwaccel-vaapi) available on GitHub that supports VAAPI.

Build the VAAPI enabled MPlayer:

Install the VAAPI enabled MPlayer (not recommended):

Instead, configure to use the VAAPI enabled MPlayer executable (Preferences->General->MPlayer executable). Next, set the output driver (Preferences->General->Output driver->User defined...) to.