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ProRes and Black Magic

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Joe Huggins
ProRes and Black Magic
on Sep 2, 2008 at 8:13:24 pm

Cow - tippers,

We transfer film to FCP in ProRes HD format using a Kona 3 card. Recently we found a client with a Black Magic Card complaining that the film transfer looked 'blotchy - like a fresco painting'. But the same footage in DVCPro HD codec looked fine. ProRes is a technically better codec apparantly, so why does it look worse? Is there any updates or compatibilty between AJA and BM that might explain this?

I'll post the same on BM site.
Thanks for any ideas.


Thanks, Film Joe


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walter biscardi
Re: ProRes and Black Magic
on Sep 2, 2008 at 8:19:07 pm

This is something we have seen with some captures with ProRes. 90% of the captures will be fine but then some just go all artifacts and blockiness. That's why we've stuck with DVCPro HD for the most part here. We let Color render the final product in ProRes.

Seems to be some underlying issues with the codec where it's good 90% of the time, but that other 10% is just bites you. There have been multiple posts in the Final Cut Pro forum about this very same deal.

Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.

STOP STARING AND START GRADING WITH APPLE COLOR Apple Color Training DVD available now!
Read my Blog!
View Walter Biscardi's profile on LinkedIn


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Joe Huggins
Re: ProRes and Black Magic
on Sep 2, 2008 at 9:39:01 pm

Thanks, I had never seen that before. Very interesting. We've been tranfering film to ProRes for some time and never noticed it before this time. So you think it has to do with the fact that it can not encode detailed images fast enough in real time, but a render is cleaner?


Thanks, Film Joe


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Jeremy Garchow
Re: ProRes and Black Magic
on Sep 2, 2008 at 11:56:56 pm

First of all, they need to be on an intel machine for ProRes to playback in HD.

Second of all, ProRes is an rt enabled codec. In the little rt menu, it needs to be set to high in order to see full raster images. Is the footage in 1080 23.98? If they have a MacPro and a bad RAM configuration, you cannot playback the images in full quality. Straightening out the RAM config (sometimes removing or rearranging the RAm to conform to Apple's specifics will fix this).

Jeremy


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Joe Huggins
Re: ProRes and Black Magic
on Sep 3, 2008 at 1:33:50 pm

Thanks Jeremy, I will check that. Joe

Thanks, Film Joe


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gary adcock
Re: ProRes and Black Magic
on Sep 3, 2008 at 12:29:03 pm

[Joe Huggins] "We've been tranfering film to ProRes for some time and never noticed it before this time. So you think it has to do with the fact that it can not encode detailed images fast enough in real time, but a render is cleaner?"

you do not mention the viewing system specs

ProRes files shown on low power intel or on G5 processor machines do not have enough CPU to show the full resolution of the captured file, displaying as little as 1/4 of that files true resolution do to the processing power that is needed for a realtime decode.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows
Inside look at the IoHD




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Joe Huggins
Re: ProRes and Black Magic
on Sep 3, 2008 at 1:35:09 pm

Gary,

That is good to know. So you think the 90%/10% random quality issue reported earlier by Walter is due to this, or is it a factor of the compression itself? Your insight seems to be more logical.

Is the file affected when it is created or just on playback? For instance we have 2 MacPros, one Quad 3Ghz 4GRam and one Eight core 2.8GHz 4GRam. Do you think ProRes created on one is inferior quality to a file created on the other? What is the minimum needed for PB or record of ProRes HQ? Is it a Ram issue? I thought all Intels would play a file but knew G5s would not create a file.

Your thoughts on the system limits would be helpful. Joe

Thanks, Film Joe


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walter biscardi
Re: ProRes and Black Magic
on Sep 3, 2008 at 1:47:51 pm

[Joe Huggins] "That is good to know. So you think the 90%/10% random quality issue reported earlier by Walter is due to this, or is it a factor of the compression itself? Your insight seems to be more logical.

Is the file affected when it is created or just on playback? "


What we're seeing is actual file degredation on capture, has nothing to do with playback only. I would follow up on the other suggestions about their system specs before you look in to bad captures. If their system meets all proper system specs for ProRes playback, then you can look to see if you had any back captures.

FWIW, I'm color grading a film right now that you guys captured to ProRes HQ and am not seeing any issues with this film at all other than the usual excessive grain on some shots.



Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.

STOP STARING AND START GRADING WITH APPLE COLOR Apple Color Training DVD available now!
Read my Blog!
View Walter Biscardi's profile on LinkedIn


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Joe Huggins
Re: ProRes and Black Magic
on Sep 3, 2008 at 2:02:04 pm

Thanks Walter. We do want to check all our variables that might add to the 'randomness' of capture degredation or playback resolution. Good to hear your current project looks good throughout.



Thanks, Film Joe


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