aq artifacts

[johnmckee]

Hello - I am having a problem with x264 aq creating artifacts - patches of (usually)green blocks in motion areas. I am encoding nature documentaries, standard definition. The artifacts are rare - like 2-3 per hour of video. I use Megui and my command line comes out like this:

program --level 3.1 --preset veryslow --tune film --crf 18 --qpmin 10 --qpmax 51 --vbv-bufsize 14000 --vbv-maxrate 17500 --no-mbtree --no-dct-decimate --no-fast-pskip --output "output" "input"
(this is the DXVA-SD-HQ profile with some tweaks..)

The artifacts go away if i decrease aq strength to 0.7
So my question is should I:
1) just decrease to 0.7 and go with it?
2) stay with normal strength and give it more bits? (still artifacts all the way down to crf13)
3) something else is wrong with my settings.
4) use other aq mode. (this fixes it but unfortunately creates artifacts in other scenes)
5) use 2pass? (same bitrate as the baseline crf - dont flame me the artifact went away!)

Before you ask I am using version I think 2230 if I am reading it correctly. Plugged into megui folder by hand.
Thanks in advance!

[LoRd_MuldeR]

Artifacts like "green blocks in motion areas" usually indicates something is going seriously wrong. This is not supposed to happen - with any setting.

It may be a bug in x264 or an issue with your particular build of x264.

...but it may as well be a bug in the H.264 decoder you use to inspect the encoded video. Or a bug in the decoder that you used to decode the source you fed into x264.

So, if you want this to be fixed, I think you should provide a complete command-line plus a source video file which can be used to re-produce the issue!

[sneaker_ger]

You're not using 10 bit x264, are you?

[mandarinka]

You should also post a screenshot of said artifacts, else people can't make an idea of what exactly are you experiencing (compression artifacts? corruption?).

[johnmckee]

Seems I mistakenly assumed moving the slider wouldn't break hardware compatibility.. In fact moving it to "very slow" removes the ref frame restriction. Sorry about the stupid post - I should have scrutinized things more.

[jpsdr]

If you don't set ref frame manualy, it's still restricted at least by the level 3.1 you've set. Now, if your HW restriction are less than level 3.1 allows, it's another story.