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Final Cut to Digibeta playout – saturation change puzzle..!
Hello,
We have been outputting graphics sequences from FCP5 to Digibeta via an AJA IO box for 4 years, with no issues. Suddenly, a couple of weeks ago, we noticed that the saturation level of pictures on the Digitape were lighter, or desaturated. Grabbing the dumped clip back in and comparing it with the original confirms that the material on tape is washed out compared to the original file. What is really weird is that if the re-grabbed clip is put to tape, and re-grabbed in again, the levels are the same, i.e. the colour change only occurs ONCE – on the first playout. The same clip re-grabbed can be dumped and grabbed indefinitely without change. We have run a number of tests, including using 2 entirely separate Macs with different FCP installations, different codecs for the original sequences including the animation codec, FCP 10 Bit Uncompressed and 8 Bit Uncompressed. Whatever we output to Digi is affected – but only once. We are running good fast Macs, the AJA IO is fully updated, we are running the latest QuickTime, and FCP is at version 5.1.4 – the latest we can run. (For info, the sequences are all 720 x 576 AfterEffects generated – UK broadcast standard PAL)
If there is anyone out there who has any inspired ideas about what this could be – we would be very grateful.
Thanks in advance, John Hunt, Bottletop Design Limited (UK)
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6 Replies
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Are you judging the change in saturation by eye? It sounds like what’s happening is that you’re finally seeing what it looks like on a non-computer monitor. Which would make things look totally different, but only when viewed from the one source. So your effective saturation isn’t really changing, what’s changing is what you’re using to look at the footage.
Can you get some scopes to play out through to check the play-out on your I/O and on your deck? I would bet that they’re the same.
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[John Hunt] “(For info, the sequences are all 720 x 576 AfterEffects generated – UK broadcast standard PAL) “
Look in your Library > Quicktime folder.
Do you have a “AJAUncompressedCodec.component” in there?
Jeremy
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Eric,
Thanks for your reply – but no, unfortunately the clips are genuinely different, as viewed in QuickTime on the Mac – direct comparison – toggling between the two, i.e. original clip has correct colours, regrabbed clip is washed out. Also scope shows colour change clearly.
Bit of a puzzle this really, because it is only suddenly an issue having had no problems for 4 years using exactly the same setup.
Thanks again / John Hunt / Bottletop Design
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Hi Jeremy,
” Look in your Library > Quicktime folder. Do you have a “AJAUncompressedCodec.component” in there? ”
No – I don’t..! There are a lot of items in there but the nearest to what you say is:
FCP Uncompressed 422.component
Does this mean anything?
Many thanks / John Hunt
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[John Hunt] “No – I don’t..!”
That’s okay, just checking something.
In your case, you do know that going from YUV in FCP to RGB in AE back out to YUV cuases a gamma shift, no?
That would explain why you see the shift once as when you layoff and the recapture the layoff, the gamma shift has happened and you are then truly in YUV all the time.
Make sense?
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Jeremy,
Yes – your comments do make sense – particularly about the one-off gamma shift, YUV to RGB. Thanks for this.
We are still somewhat puzzled, however, as this has never occurred before 2 weeks ago. In fact, since your last post we have dug out an older digi tape of the identical material dumped out a year ago for the same client using the same Mac, FCP, Io and deck, and there is no colour shift on that tape..!
I guess we will just have to compensate with the colour when we originate stuff in AE.
Thanks again for your time.
John / Bottletop
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