VAAPI

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

Installation
VAAPI support can be enabled system-wide by setting the  variable to.

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

The system needs to be updated if the  variable was set to.

Usage
Run vainfo 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.