Libva tires to load pvr_drv_video.so (not found) in WebEngine

[Iheb]

I'm using Lemaker Guitar board with Ubuntu Mate vivid 15.04 and I have a Qt 5.8.0 application on it that uses device to device communication with webrtc on QtWebEngine. When the communication starts I've got this log in Qt:

libva info: VA-API version 0.37.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/pvr_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.37.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/pvr_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.37.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/pvr_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.37.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/pvr_drv_video.so
libva info: va_openDriver() returns -1

pvr_drv_video.so indeed doesn't exist in the device and I couldn't find it anywhere. What's the main use of libva in QtWebEngine? Why it tries to load pvr_drv_video.so? Where can I find/build it?