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DPX, Aja DPXtoQT, GlueTools, what the best 2K workflow?

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carlo.motzo
DPX, Aja DPXtoQT, GlueTools, what the best 2K workflow?
on Feb 19, 2007 at 1:53:55 pm

I have to solve a visualization problem in FCP and QTime.
And I hope my experience will be useful to all.

I have to edit a 2K film with a Mac Pro 3.0 (Quadro FX card, 4Gb ram, 10.4.8) with a 4 Gb/s RAID capable of 700 Mb/sec.
No KONA3 card: for me it's ok to visualize the film on a 30" Cinema Display.
I received 2K DPX files 2048x1556 (10 bit log RGB); the editing will be done in FCP, using as sequence setting the AJA 2K 10-bit log RGB.
A Kona3 card is mounted on a second Mac Pro, so I decided to wrap the DPX files using the DPXtoQT Aja converter.

First surprise: if I use Aja DPXtoQT converter to obtain a Quicktime movie, the log gamma isn't correctly applied and I obtain a greyish movie. The controls of the DPXtoQT don't solve the problem.

Second surprise: the self contained movie has a lower playback than a reference movie. Only using a reference movie I can obtain an acceptably smooth playback. But not real time: maybe 10/15 fps. Only at 50% zoom in FCP I have a true realtime playback. And, surprisingly, using canvas viewer is better in terms of fps than using the 30" as video playback display.

Third surprise: the resulting movie is seen as 8 bit by Shake. I haven't tried yet with QTtoDPX converter. A major problem.

So, I tried the GlueTools DPX components to obtain a reference movie. Fantastic: I have greater control on the process. But...

- the reference movie is (slighty) slower in playback in FCP
- I couldn't find a clear documentation about the rather obscure GlueTools' settings (surely my fault...)
- I cannot create a DPX/GlueTools sequence in FCP. because the GlueTools components are not a codec. So, I have to use the AJA 10-bit Log RGB codec and the Export Movie with Quicktime conversion command. But I suppose this will re-compress each frame (am I wrong?) degrading the quality.

Is there anybody that solved successfully the problems I found on my 2K way (or anyone that found a better workflow?).

Many thanks.





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chrispy
Re: DPX, Aja DPXtoQT, GlueTools, what the best 2K workflow?
on Feb 19, 2007 at 3:03:18 pm

Check out Silverstack from Pomfort : http://pomfort.com/silverstack/

You can use this application to batch convert your 2K DPX files into Quicktime movie files using any codecs and it will embed the DPX timecode into the Quicktime timecode so you can convert using PhotoJPEG codec for offline editing, which is still excellent in picture quality, consume less storage space and you don't need a high speed RAID.

But best part is that you can linearise your DPX files when converting to the Quicktime movie files and it can also burn timecode, clip name...etc. info into the Quicktime movie files.

Go check it out, it's what you're looking for. And it has just officially launched so you're in luck !

-chrispy


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gary adcock
Re: DPX, Aja DPXtoQT, GlueTools, what the best 2K workflow?
on Feb 19, 2007 at 4:49:54 pm

[carlo.motzo] "I have to edit a 2K film with a Mac Pro 3.0 (Quadro FX card) with a 4 Gb/s RAID capable of 700 Mb/sec. No KONA3 card: for me it's ok to visualize the film on a 30" Cinema Display."

Carlo- that is one beefy array to have and not be using a video card - are you sure that it will do that speed? By my estimate thats at least 24-36 disks over 4 channels of 4G fibre.

"First surprise: if I use Aja DPXtoQT converter to obtain a Quicktime movie, the log gamma isn't correctly applied and I obtain a greyish movie. The controls of the DPXtoQT don't solve the problem."

the Kona LUT controls are not meant to be used without a Kona Card. The LUT controls are used for preview not baking the look into you video.

"Second surprise: the self contained movie has a lower playback than a reference movie." not sure what you mean by this-- but yes it is possible to have a self contained movie have lower playback needs than a DPX seq.

"Only using a reference movie I can obtain an acceptably smooth playback. But not real time: maybe 10/15 fps" Even with a Kona 3 card the playback is limited when working with full frame 2K content, an advantage to the K3 is that it has the ability to play the 1920x 1080 over HDSDI at full 23.98 fps frame rate.

"Only at 50% zoom in FCP I have a true realtime playback. And, surprisingly, using canvas viewer is better in terms of fps than using the 30" as video playback display." yes to both. the canvas is smaller and meant to play material correctly - and I have never seen any video card be able to play @100% on a 30in Cinema Display.

"Third surprise: the resulting movie is seen as 8 bit by Shake. I haven't tried yet with QTtoDPX converter. A major problem." that one is operator error - QT needs to be set to 10bit.

[carlo.motzo] " So, I have to use the AJA 10-bit Log RGB codec and the Export Movie with Quicktime conversion command. But I suppose this will re-compress each frame (am I wrong?) degrading the quality. "

Thats why you use a REF movie so that you do not need to re-compress every frame. however if you use Glue tools correctly you should be able to match back to the DPX seq frame for frame.

I have been working with GLue tools alot lately and have come to really enjoy it.


gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows


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