Why do I have strange artifacts in my encode

[ShortKatz]

I've encoded two movies of mine using HandBrake and the x265 encoder into HEVC. Both movie files suffer from pixelated artifacts.
Here are some screenshots:
https://imgur.com/LMiDEIT
https://imgur.com/ffnEmqB
Sadly this is not reproducible if I only encode this scene. I've cut out the effect sequence of the original file and encoded only this piece, which turned out to be perfectly fine. Recently I've changed my x265 encoding options, so maybe I now have a bad combination or have chosen a delicate option?

I used x265 3.5 RC1 and preset "slower" with the following options:

--early-skip --no-rect --no-amp --no-sao --rd-refine --opt-cu-delta-qp --no-strong-intra-smoothing --psy-rd=3 --psy-rdoq=0 --hme --hme-search=hex,umh,star --rskip=2

All I've changed to my previous encodes was, I switch from preset "medium" to "slower" and I've added --no-rect --no-amp --rd-refine --opt-cu-delta-qp --rskip=2.

I've never before have seen something like this with x265, so I'm a bit puzzled what this could be. I also have no idea why I cannot reproduce this with the affected sequence only.

[poisondeathray]

Rule out a decoding/playback issue first . Try something else like mpv, ffplay

Run some hardware stability tests. Memory integrity, psu etc... If you're overclocked , revert to defaults

If you can't reproduce with just that scene, try encoding a segment that includes a few scenes before and after

[Boulder]

What is your script? I've seen those with MDegrain but pinterf's latest version of MVTools has fixed them.

[ShortKatz]

Originally Posted by poisondeathray

Rule out a decoding/playback issue first . Try something else like mpv, ffplay

Run some hardware stability tests. Memory integrity, psu etc... If you're overclocked , revert to defaults

If you can't reproduce with just that scene, try encoding a segment that includes a few scenes before and after

I've tried with Apple Quicktime, VLC and ffplay. It looks all the same. hardware stability test told me, all is fine. Nope, I did not overclock. I will try your suggestion with the scenes before, thanks.

Originally Posted by Boulder

What is your script? I've seen those with MDegrain but pinterf's latest version of MVTools has fixed them.

I did not use a script. Its just HandBrake with an updated x265 and some "Additional options". I used the same build for the same movies before, but with a different preset and different x265 options. And all was fine at that time.

[charliebaby]

try with staxrip and update your FFMPEG and take the x265 stable version and see if it's good

[quietvoid]

That's a rskip 2 problem AFAIK, it was mentioned before in the x265 thread.
https://forum.doom9.org/showthread.p...61#post1920461