stair stepping / Alaising-Effect on 4K videoinput

[Bodo]

Hello All,

I have a 4K input (from panasonic lumix gh4) on a PCI decklink mini Recorder 4k / Win 10, i7, Quattro M4000, Isadora 3.8 there is a very visible stair stepping / Aliasing Effect on all the lines/boarder of the objects (even with full frame antialiasing on in the preference video tab) -  as i want to capture a live drawing of an artist (and zooming in to the 4k quality) it is really a problem (alls the line of the drawing are stairs) if I switch to 1080p the problem is gone - anyone an idea how to fix this? 

best Bodo

[Bodo]

actually if I zoom close and it is real in focus i see the stair stepping-effect even in 1080p....

[DusX]

@bodo

can you provide screen grabs to show what you are seeing?

[Fred]

Check you are actually getting proper 4k from your HDMI. The GH4 can output scaled resolutions over HDMI. Also check it with a 4k monitor to see if you have the same issues, also try make a recording with the blackmagic software and check to see if the recording has the same issues.

Try these instructions

https://www.lensrentals.com/pr...

[Bodo]

@fred - Thank you very much I will try this!

[Bodo]

@fred and DusX - attached a screenshot 1. Isadora capture and 2. media express recording under same conditions - there is the aliasing effect with Isadora and not with media express???

[Bodo]

@dusx 

hi dusx - I did a screenshot of the effect I mean and a recording with media express (which does not has this effect) - any idea why Isadora make this aliasing effect with the incoming stream and media express not?

thank Bodo

[m_theater]

@bodo

i think that the internal scaling isn't working for you.

could you make a screenshot of the actual stage in 1920x1080, the floating preview window is not a good reference.

I think it would be worth to check how your 4k footage is presented on a a 4 screen, if you have non around you could emulate one with your quadro.

and check the difference in the screenshots.

from my point of view: if izzy is working correctly there shall be no influence apart from the yuv -> rgb transformation in the picture if you have a 4k camera / 4k processing / 4k screen.

if that is working correctly, perhaps you need a custom shader for a proper scaling

best clemens

[DillTheKraut]

@bodo

did you check your default resolution settings in preferences?

[Bodo]

@dillthekraut - it is set to HD - should be 4k?

[Bodo]

@m_theater thanx for reply - I will check this when I`am back in the studio we have a 4k Monitor there...