Re: [Nuke-users] Artefact Issues with Greenscreen Alexa (ArriRaw)
Hi Realised after that these were converted movs so I had lost the raw. However we had got different results in 6.2 on windoze over 6.3 on mac. Thanks for the other insights though hugh! Howard On 30 Jul 2012, at 18:57, Hugh Macdonald li...@hughmacdonald.co.uk wrote: I'm not sure that this is exactly the same issue that you're having, but I spent some time testing out different export settings (using the ArriRaw Converter - http://www.arri.com/camera/digital_cameras/tools/arriraw_converter.html) My preferred settings file is this: arri arriraw shortsettings name=ARC version=2 colorhandling param name=colorspace value=WideGamut / param name=colorencoding value=logc / /colorhandling downscale param name=crispness value=0.0 / /downscale quality param name=debayer value=ADA-2 SW / /quality output param name=format value=dpx / /output /shortsettings /arriraw /arri To explain the choices in here: colorspace : This seems to be the standard. I didn't want to mess with this too much colorencoding : If exporting to DPX, then LogC is Arri's own log encoding curve crispness : This is a value between 0.0 and 3.0. It defaults to 1.0. I found that setting it to 0.0 gave the cleanest image. This is only used when down-scaling. debayer : This is the main one. There are 4 options here - ADA-1 HW (which is what the camera does internally for monitor outputs), ADA-2 SW (a second version), ADA-3 SW (the most recent version) and ADA-3 HW (the most recent version with optimisations for future hardware). ADA-3 (both types) gives horrible edges if there's any amount of contrast. Have a look at the attached image for an example (ignore the delivered column) format : DPX, obviously, as we're going to LogC. An ACES/scenelinear/EXR combination would be another valid option here. (Although before you freak out at how yellow the ACES colourspace looks, get someone to explain the ACES gamut to you...) Anyway, this is a bit of a sideline from your original query, as that does definitely look like a subsampling thing to me, but I thought I'd add my input to general Alexa settings. Hugh Macdonald Visual Effects Supervisor nvizible – VISUAL EFFECTS On 26 July 2012 10:53, Howard Jones mrhowardjo...@yahoo.com wrote: 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
Re: [Nuke-users] Artefact Issues with Greenscreen Alexa (ArriRaw)
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 ___ Nuke-users mailing list Nuke-users@support.thefoundry.co.uk mailto:Nuke-users
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 ___ Nuke-users mailing list Nuke-users@support.thefoundry.co.uk mailto:Nuke-users@support.thefoundry.co.uk, http://forums.thefoundry.co.uk/ http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users ___ Nuke-users mailing list Nuke-users@support.thefoundry.co.uk, http://forums.thefoundry.co.uk/ http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users ___ Nuke-users mailing list Nuke-users@support.thefoundry.co.uk, http://forums.thefoundry.co.uk/ http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users -- 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 Nuke-users@support.thefoundry.co.uk, http://forums.thefoundry.co.uk/ http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users
Re: [Nuke-users] Artefact Issues with Greenscreen Alexa (ArriRaw)
Do you have access to the original Arriraws? If so, you could try to debayer them again in the Arriraw converter with a different setting (reducing sharpness to 0, for example). Here is where you can get the converter from: http://www.arri.com/camera/digital_cameras/tools/arriraw_converter.html On Jun 29, 2012, at 10:26 AM, Aélis Héraud wrote: -- 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. Mail Attachment.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 ___ Nuke-users mailing list Nuke-users@support.thefoundry.co.uk, http://forums.thefoundry.co.uk/ http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users ___ Nuke-users mailing list Nuke-users@support.thefoundry.co.uk, http://forums.thefoundry.co.uk/ http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users
