Yes maybe there is a way recompling chromium-codecs-* packages.
I didn't have time to take a look ont it.
I think it can be easier with firefox, I explain in the lasts builds of firefox if ffmpeg (then libavcodec) is installed firefox use it by default.
So I write a tutorial how to compile ffmpeg/libavcodec with video hardware acceleration but it don't work because it is no possible to choose an hardware acceleration or a specific video codec.
My idea is changing source code of ffmpeg to switch h264 codec code by h264_mmal codec which have hardware video decoding.
I need some time to do it, if you wanna try and know C languages the files are in libavcodec directory h264.c and mmaldec.c.
I will try soon but it needs some time
Maybe same trick is possible in chromium rebuilding the packages of chromium-codecs or/and chromium-codecs-extra because I know it is based on ffmpeg too.
Yes, I write some tutorials about it, if you want but hardware decoding only works on fullscreen for now. try the OpenMax-Il version it is stable, MMAL version is buggy (I think we must want a new version for mmal stuff, I think vlc team based his work on old version of firmware).
Could you try some hd video in OPENMAX-IL version with GLX output ?
GLX output works with the opengl driver (I tested it with no hd video) but I don't know if vlc uses openmax decoder in that video output.
Another solution for video decoding in windoded / fullscreen mode with hadware video decoding for playing hd video is mpv.
I will try to write some tutorial about it soon too ! And it work with great GUI like SMplayer or bomi !
I don't know, I try the new driver only on lubuntu (https://ubuntu-pi-flavour-maker.org/) because I have a old sdcard of 4GB for tests and mate need more space for playing with it.
I will try mate this weekend.
I have a bug too in raspbian or lubuntu, I have a old 4/3 screen (1280x1024) and there is space not used too but in the bottom !
I can't put my mouse pointer in it.
I will try with mate this weekend I will tell you, I will try with my hd tv too because I only have an old school monitor with DVI input
The input of your screen is HDMI ? or DVI ?
I think both but I am not sure, I think the best is to have an alpha version of next ubuntu (xenial) to make better tests because it have the good version of mesa out the box, so we don't need to make dirty updates of the mesa packages !
The build are made with https://ubuntu-pi-flavour-maker.org/ so maybe it's possible to build the alpha version of xenial or ask the team to provide it.