Did you get a good answer to this - just by coincidence I'm seeing this on some
footagr today too, and it not the issue I had had previously
Cheers
Howard
>________________________________
> From: Howard Jones <mrhowardjo...@yahoo.com>
>To: Nuke user discussion <nuke-users@support.thefoundry.co.uk>
>Sent: Thursday, 5 July 2012, 10:27
>Subject: Re: [Nuke-users] Artefact Issues with Greenscreen Alexa (ArriRaw)
>
>
>Yes in all fairness the company never got to the real cause of the fault, but
>thought it was a cable and it may not have even been an alexa but another high
>end camera, however caused though it did result in 1/2 res red and blue
>channels which were unfixable without a more sophisticated version of the
>solution I outlined.
>
>
>Hopefully getting back to source will fix it, if not then it will be the 2nd
>time I have come across this.
>
>
>Howard
>
>
>
>>________________________________
>> From: Holger Hummel|Celluloid VFX <hol...@celluloid-vfx.com>
>>To: Nuke user discussion <nuke-users@support.thefoundry.co.uk>
>>Sent: Tuesday, 3 July 2012, 21:06
>>Subject: Re: [Nuke-users] Artefact Issues with Greenscreen Alexa (ArriRaw)
>>
>>
>>Hi all,
>>
>>what Alex said is probably a good option.
>>i chatted to a friend of mine who's close to all the technical camera-related
>>stuff.
>>his answers in short form:
>>
>>1) wrong cabling would most likely result in wrong colors
>>2) check which camera firmware and recorder was used
>>3) check which ArriRaw Converter version was used, 2.3 being the newest -
>>since today, actually (that
link you already got from Alex)
>>
>>last but not least, post it on the official Arri forum. there's a chance of
>>having someone from Arri reply to it
>>
>>http://forum.arridigital.com/forum/
>>
>>cheers,
>>Holger
>>
>>
>>Aélis Héraud wrote:
>>> Hi Howard, hi Alex
>>>
>>> Thanks for the tips guys, we tried the TVIscale, that seems to help a bit
>>> more than bluring the red channel, we're still looking for a lossless
>>> solution but the TVIscale could be our best option so far.
>>> We're waiting for some original Arriraw footages in order to test the
>>> Arriraw converter.
>>>
>>> I'll give you feedback if we find a way to fix the problem.
>>>
>>> Thanks again,
>>>
>>> Aélis
>>>
>>> On 6/29/2012 11:02 AM, Howard Jones wrote:
>>>> I had something similar once - where a cable had been plugged in wrong.
>>>> Basically both R and B were
1/2 res blown up to full size. ie like proxies.
>>>> The quick solution was to rescale to 1/2 res at impulse then resize with a
>>>> better filter. It worked to a fashion.
>>>> I didn't try TVIscale but that might be worth a go.
>>>>
>>>> Assuming that is the issue of course. The blue has been rubbish on a
>>>> number of shots for me too.
>>>>
>>>> Howard
>>>>
>>>>
>>>>------------------------------------------------------------------------
>>>> *From:* Aélis Héraud <aher...@gmail.com>
>>>> *To:* nuke-users@support.thefoundry.co.uk
>>>> *Sent:* Friday, 29 June 2012, 15:26
>>>> *Subject:* [Nuke-users] Artefact Issues with
Greenscreen Alexa
>>>> (ArriRaw)
>>>>
>>>> -- Okay, I had some trouble sending this mail last night so I
>>>> hope you'll receive it now. Sorry for duplicates copies. --
>>>>
>>>> Hi folks, I'd like to ask you something.
>>>>
>>>> We have to deal with some greenscreens in Alexa and I know some
>>>> people have had some trouble with it. Overall the greenscreens
>>>> are pretty good and we're able to get a good result, but we
>>>> noticed something on the data and I'd like to have your say on
>>>> this matter.
>>>>
>>>> We noticed some artefacts in the Red and Blue channels,
>>>> especially on the thinner blond hairs.
>>>> The plates are in 2880x1620, it was recorded in
ArriRaw (via
>>>> T-Link) and then converted in DPX (Colorspace AlexaV3LogC) so
>>>> it's pretty much the best quality we can have, there's no
>>>> compression.
>>>>
>>>> RGBsamplesAlexaArriRaw.png
>>>>
>>>> As you can see the RGB seems pretty much ok and the green channel
>>>> is good, but the red one has some pixels in staircase and I won't
>>>> even talk about the blue one. The last picture is a first key.
>>>>
>>>> After some investigations we're pretty sure it has something to
>>>> do with the debayering process. It's maybe due to the algorithm,
>>>> the interpolation between pixels isn't very good in the red and
>>>> blue channel. I don't know exactly but that's the only
>>>>
explanation we could come up with so far.
>>>>
>>>> My question is : Is there a way to fix it in Nuke without
>>>> altering the data (the good one) or are we stuck with that ? Any
>>>> idea ?
>>>>
>>>> I tried to split the channels and to put a blur at 1 on the Red
>>>> one and it seemed to help a bit at first but eventually we can
>>>> feel the softness and we lose the thinner hairs, which I'd like
>>>> to avoid. I'd keep that as my last option.
>>>>
>>>> Our other option would be to ask the company who did the
>>>> debayering but I'd like to find another way.
>>>>
>>>> Thanks for the help
>>>>
>>>> Aelis
>>>>
>>>>
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>>>>
>>>>
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>>>
>>> ------------------------------------------------------------------------
>>>
>>> _______________________________________________
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>>
>>-- Holger Hummel - hol...@celluloid-vfx.com
>>
>>Celluloid Visual Effects, Paul-Lincke-Ufer 39/40, 10999 Berlin
>>phone +49 (0)30 / 54 735 220 - m...@celluloid-vfx.com
>>
>>_______________________________________________
>>Nuke-users mailing list
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>>
>>
>
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