Unusual x264 compression artifact

[Mephesto]

This is the weirdest artifact I've seen so far. Previously, I've seen major SSIM-crushing differences that were noticeable but not degraded quality, just different.

And this is not a playback error. This scene is flickers of explosions reflected on that building, but it's not just the chroma that changes but the shape also slightly shifts. The frames of the yellow and blue right-hand building differ consistently, but the blue building in the compressed frame matches the shape of the yellow building in the source.

My videonerd friends, you have witnessed a major parametric artifact. This is the coming of a new age where lossy video compression will cease to be the uniform mess of shit we're used to with blurring, blocking, smearing and ringing. Soon, bitrates will go down dramatically and the contents will be altered without being wrecked. Milla Jovovich having blue hair instead of orange might be the difference between 700 megs and 700 kilos.

Awaiting H.265 with an impending orgasm...

[deadrats]

out of curiosity, what settings are you using? any psychovisual enhancements being used?

[hech54]

Someone needs a shrink.

[Mephesto]

out of curiosity, what settings are you using? any psychovisual enhancements being used?

I never use psychovisuals, they make the noise worse.

cabac=1 ref=16 deblock=1:1:1 analyse=0x3:0x133 me=tesa subme=11 psy=0 mixed_ref=1 me_range=24 chroma_me=1 trellis=2 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=0 chroma_qp_offset=0 threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=16 b_pyramid=2 b_adapt=2 b_bias=0 direct=3 weightb=1 open_gop=0 weightp=2 keyint=288 keyint_min=23 scenecut=40 intra_refresh=0 rc_lookahead=250 rc=crf mbtree=1 crf=19.0 qcomp=0.70 qpmin=10 qpmax=51 qpstep=4 ip_ratio=1.40 aq=2:1.00

Someone needs a shrink.

That's what I thought about Dark Shikari when he talked about developing mb-tree. I've learned never to be normal again since. Jump on the bandwagon, mofo.

[poisondeathray]

Post a sample of the source

What binary are you using ?

[jagabo]

Awaiting H.265 with an impending orgasm...

What makes you think h.265 won't generate similar or other artifacts on occasion?

[El Heggunte]

Mephesto wrote:

lookahead-threads=2

Set it to 1, and see if it makes some difference ( for better, of course ).

[Mephesto]

Post a sample of the source

What binary are you using ?

I can't, I've deleted the source. But I have other encodes and comparing them side by side shows that this frame was the only one where this particular problem occurred. That orange reflection happens on every other frame during the explosion and ALL buildings turn orange, not just two.

Heres a small sample. Left one is a crappy low-bitrate encode someone did many years ago, right one is mine.

I am using the latest 2230 x264.

What makes you think h.265 won't generate similar or other artifacts on occasion?

I think they'll happen more often, which is awesome. Parametric artifacts are way better than uniform ones. H.265 is a means, not the end. It will take one more codec generation but the days of low quality will be over.