4K 10 bit HEVC output has pixelation/color issues with output.

[Former user]

When 4K 10 bit HEVC (profile - main 10) outputs are created there are pixelation/color issues with the output. Also, making the same output with 8 bit HEVC (or X264) doesn't cause show the same issue. Just using a preset of main will show the issue, but I was mainly using Ultra Fast while testing. Source is 1280x544 at 23.976 and output was also at 23.976 (pixelation color issue also present with frame rate at 29.970). With the output the issue is very easy to spot at the 28-30 second mark. Screenshot showing issue is attached.

[Steve Borho]

What rate control settings were used for this clip?

[Steve Borho]

Also, I'm a bit confused when you saw 4k 10 bit HEVC at the beginning and 1280x544 later on. Can you elaborate on that?

[Former user]

The source was 1280x544, but the output was 3840x2160. For rate control I was using average bit rate (I believe that I was using 10Mbps, but I'll have to double check). Sorry for any confusion.

[Steve Borho]

x265 doesn't have any scaling features, so I assume you mean the image was scaled prior to the encoder, which is perfectly ok.

would it be possible to provide us with the encoded bitstream? I am curious how that slice and those blocks were coded.

Also it would be helpful if you tell us what version of the encoder you used. There have been many recent bug fixes.

[Former user]

We are currently using X265 fe3fcd9838c0. I'm adding the X265 output that was made as well.

Sorry for taking a bit to get back to you.

[Steve Borho]

I suspect this was caused by the bug fixed in e03388e98ecc

[Steve Borho]

vbv: clear row diagonal and cu SATD costs after vbv row reset was triggered

refs #45

→ <<cset 166e4d6e819e>>

[Steve Borho]

vbv: clear row diagonal and cu SATD costs after vbv row reset was triggered

refs #45

→ <<cset 03525a77d640>>

[Steve Borho]

Resolved by <<cset b77ca886ef3b>>