Can someone with Kona2, a HD capable monitor and After Effects confirm this?

[Jeremy Garchow]

Are you trying to downconvert your HD footage to preview the SD image? If so you should use the Kona 2 to downconvert the signal and not change AE preferences.

———–
G5 Dual 2Ghz <> 4GB RAM <> FCP 5.04 <> Kona 2
ATTO 42XS <> Huge Systems 4105 Fibre
OS 10.4.2 <> QT 7.0.3

[Grant Lovering]

I’ve tried downconverting both ways, when you change AE’s output it dynamically switches it in the Kona control panel.

The real crux of the issue is highlighted when you take a HD clip and put it in a HD comp and output HD then create an SD comp and put the same HD footage in that scaled down to SD and the output is significantly different, when really the only difference should be the resolution. This takes any conversion process out of the picture.

It is almost like the colour space is being handled differently in AE between HD and SD output via Kona. The biggest issue apart from the inconsistancy is knowing which one is correct.

Any clues?

[Jeremy Garchow]

[Grantly] “Any clues?”

Sure, a few. Of course if you change the AE preferences, it’s going to dynamically change the Kona output, it’s what you are telling the Kona to do. If you have an HD comp and want to view it in SD then you should leave it in an HD comp, and use the kona control panel to downconvert your HD signal. Select your secondary output to be whatever flavor of SD you want (525, 625, whatever frame standard your HD material is based on) and then select whichever output you are using to monitor (SDI 1,2 or analog component). Now, switch the output of that pipe from primary to secondary. There’s also color space conversion in the K2 control panel from 709 (hd) to 601 (sd), automatic and other choices. You can choose what you want. Also, don’t forget (if you’re working in US NTSC) about analog setup levels. That might account for the ‘gamma’ shift you seem to be experiencing.

Jeremy

———–
G5 Dual 2Ghz <> 4GB RAM <> FCP 5.04 <> Kona 2
ATTO 42XS <> Huge Systems 4105 Fibre
OS 10.4.2 <> QT 7.0.3

[Gary Adcock]

[Grantly] “The real crux of the issue is highlighted when you take a HD clip and put it in a HD comp and output HD then create an SD comp and put the same HD footage in that scaled down to SD and the output is significantly different, when really the only difference should be the resolution. This takes any conversion process out of the picture.”

Are you taking into account that the color spaces are vastly different. There is not really such a thing as “broadcast safe” in HD. What were the results with playout via the free Kona TV app? if they are the same then it would be a hardware issue, if not you need to look into what and how you are working.

SInce you did not mention any of the hardware or software versions you are working with we can only guess at your problems.

Gary Adcock
Studio37
HD and Film Consultation
Chicago, IL USA

[David Battistella]

Plus in SD youare dealing with a 7.5 set-up which does not exist in HD since the setup is zero.

You almost are best to set up your monitor to grade in HD with HD Bars and scope.. When that master is graded you need to reset the monitor for a traditional SD CC. I would duplicate the sequence and tweak it for the SD downconvert bars and levels.

It’s not just interchangable you have to run two “looks/presets” for your monitoring.

David

I can’t believe it’s not butter!

[Grant Lovering]

Ok, forgot to mention we are working in PAL, so the 7.5 issue isn’t a factor.
Running Latest FCP and AE 6.5.1 and Quicktime 7.0.3.

I noted we had our colour space and gamma set to auto which appears to be working correctly. I manually changed between 601 and 709 and it showed the same problem.

I didn’t get a chance to check KonaTV today but I think I tried that at the time and had the same problems.

I understand there are difference between SD & HD colour spaces, but I would have thought that if you grade something in HD and then create a SD version it should translate without the need for a significant re-grade. FCP behaviour seems to reinforce the theory, it’s just AE.

If I have left out any info or specs that may be helpful to solving this please let me know.

Thanks heaps for everyones input and help it is much appreciated.
Cheers,
G.

[Grant Lovering]

Okay….we have worked out where the error is and the temporary workaround that provides even image across the board.

Installed new drivers (which also removed the codec below) and the problem is still there.

If we either leave the control panel set to auto or manually set the 609/701 colour spaces FCP handles the conversion correctly with no perceptual difference, whereas AE in an HD output has a massive gamma shift (image becomes considerably darker).

The workaround to solve this is;

For working in FCP leave the control panel set to auto and SD/HD monitoring is correct.
For working in AE leave ColourSpace set to Auto and manually set Gamma to 601 regardless of SD or HD video output and the huge gamma shift is gone. I