[Libva] H.264 encoding quality on Haswell and Broadwell

[Nikita Orlov]

Hello friends!

I have tested h.264 encoding using libva 1.6.0 (+ intel driver 1.6.0) on Haswell HD4600 and Broadwell Iris Pro 6200.
Under linux I used avcenc, h264encode (as I understand it is somehow deprecated and i must use avcenc) and gstreamer plugin.
I downloaded big buck bunny 1080p mov file, using ffmpeg I convert first 60 sec of video to raw yuv420 (ffmpeg -i ./bunny.mov -c:v rawvideo -pix_fmt yuv420p ./out.yuv).
Mostly I am interested in CBR.
Quality is very bad, using CBR 1 Mbit/s all picture is covered by artefacts, 5Mbit/s give better result, but still there are some artefacts.

I compared it with encoding the same video under Windows 7 sp1 using latest Handbrake. It gives much better results. 1Mbit/s under windows gives good picture, 5Mbit/s give in some terms perfect picture.

As I understand only diff is drivers or wrapper of drivers.

So. my question is how to tune h.264 encoding using libva under linux? Are there some hidden settings? I mean settings that are not exist in avcenc/h264encode cmd, but exist in sources.
Or maybe some settings are not implemented even at drivers level of libva.
Or I doing something completely wrong.

Pls help :-)

-- 
Nikita Orlov
Skype: nik_stet
QQ: 2717846083