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RGB/YUV and Kona 2/3

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Kevin Watkins
RGB/YUV and Kona 2/3
on Jun 21, 2007 at 6:12:54 pm

I'm having a strange problem with some 35mm footage I had transfered at a NYC post house and wonder if you can help...

The post house transfered the footage from the 35mm to HD Cam SR and then brought that into FCP 5.1 with a Kona 3 card and version 3.4 drivers. Quicktime files were outputted from there and dropped onto a drive for me. I requested the files as be AJA 10 bit RGB 1920x1080 @ 23.98 with instructions to stay 4:4:4 all the way.

Once I dropped them into a matching sequence I noticed a strange stuttering effect. I'm on FCP 6, with a Kona 2 card and version 4.0 drivers. In a discussion with the post house they tested the footage and found that they could view it perfectly when the setting was Kona 10 bit 23.98 fps but also saw the stuttering when they viewed it as kona 10 bit RGBA 23.98 fps. They suggested rendering it out as Kona 10b 23.98, which I tried and it works...

Thing is, if the codec is Kona RGB 10b 23.98 why on earth would it not play back? Why does it work when converted to a YUV codec? Is it possible they somehow outputted a YUV file but wrapped it in RGB somehow? Is there a way to check?

The film I'm working on is a combination of animation and live action. The animated files out of AE are AJA 10b RGB 23.98 and they play perfectly (no stuttering and they are stop-motion!) I am hoping to stay 4:4:4 all they way through color correction but the AJA YUV codec is 4:2:2

The system is a dual 1.25 Ghz G5 PPC, $gb RAM, Kona 2, Apple Xserve RAID (AJA test: write 187MBs Read 262MBs) ATI Radeon X800, Black Magic Decklink for monitoring on 23" Apple, 20 inch Sony PVM for NTSC monitoring. The film is only 12 minutes, of which 4 minutes are live action.

Any thoughts would be appreciated.

(Sorry this is so long but I want to provide as much info as possible.)


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gary adcock
Re: RGB/YUV and Kona 2/3
on Jun 21, 2007 at 6:49:02 pm

[Kevin Watkins] "Apple Xserve RAID (AJA test: write 187MBs Read 262MBs) "

this would be the first place to look.
the raid should be closer ( ie: nearly the same) in the read / write specks as you are pushing not quite 200 mgs a second

are you sure cache flushing set to off in the raid admin and it is a fully populated raid?



gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows


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Kevin Watkins
RAID Cache
on Jun 21, 2007 at 7:47:23 pm

The drive is populated with 14 drives, 2 banks of 7 in RAID 5. 'Allow Host Cache Flushing' is off (Controller Write Cache and Drive Write Cache are both enabled). Interestingly the AJA test has a Disable Files System Cache option, which if I un-select, the write/read goes down to 179MBs/163MBs. Running this test using the 4GB file at 1920x1080 10b RGB setting.

The other files I have do not stutter, only the transfered files...so would that still indicate the RAID as the issue?

Thanks for your input. I'd like to figure this out.


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Bob Zelin
Re: RAID Cache
on Jun 21, 2007 at 9:51:27 pm

262mb/sec is enough read time speed to do this HD image size. I don't know why this is happening, but are you really using a dual 1.25 G5 ? I don't even remember this machine. Wasn't the slowest G5 a 1.8, and the duals were 1.8 and 2Gig. Can your machine work at HD speeds ?

Do you have access to an HD-VTR at your facility, besides this file transfer ? You should try to input your own material, and see what happens.

Bob Zelin



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Kevin Watkins
HD VTR
on Jun 21, 2007 at 10:13:49 pm

Sorry, its a 2.7GHz dual (I have no idea why I got that wrong...old age?) I'm happily watching the rest of my animated files, its just the transfered stuff I'm struggling with (they are inter-cut on the same timeline.) If I create an AJA 10b uncompressed (YUV 4:2:2) time line, drop the clip on it and render, it plays fine...I can watch the QT file on the desktop no problem...Its just when its on a timeline that EXACTLY matches its codec, with the playback set to the same setting, that I have trouble. Like I said, the animated clips play fine, which means to me that something is wrong with these transfered files - but what?

One interesting thing, the Quicktime info window shows these clips as not being exactly 23.98 (they vary from 23.5 to 24). The post house assures me this is not a problem and QT is wrong. My files are all reading as exactly 23.98...anyone heard of this before?

As for a 'VTR at my facility', er, its just me in a small office in NYC. I had them transfer the files to save myself the cost of the deck rental. They are not some small post house either. So it must be me...


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Kevin Watkins
Its a know bug!
on Jun 22, 2007 at 6:30:47 pm

I spoke with AJA and this is a know issue. Version 4 of the driver has problems with playback in RGB 4:4:4. AJA suggests 'downgrading' to FCP 5.1 and AJA driver 3.4. That's a problem. Yet another reason why upgrading in the middle of a project is a really bad idea. (I need Color, so I figured I'd risk it.)

It still doesn't solve some oddities about this but at least I have a rough idea of what's wrong.


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keicol
Re: Its a know bug!
on Sep 22, 2007 at 4:09:06 am

Is this still an issue, or has it been addressed?


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