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720P 10-Bit Reality Check

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Jeff Bernstein
720P 10-Bit Reality Check
on Oct 3, 2006 at 6:50:49 am

I just wanted to get a reality check on a disturbing recent discovery and wanted to know if others are seeing this. We are able to repeat this on several systems.

On a 720P 10-Bit Uncompressed Sequence, we are seeing inaccurate layoffs. Interestingly, we can get the first frame of video to consistently layoff, but after a few minutes of running time, the timeline starts to first slip by 1 frame, then a couple of minutes later, 2 frames, etc.

In our tests, it has been with graphics layoffs whereas there will be 5-10 seconds of video, then 5-10 seconds of slug, and so on. We have even replaced the slug with captured black to no avail.

Now here is where it gets interesting, if we export the sequence as a QT reference movie, or a self-contained movie, you will see similar slippage. Not only in playing it out, but you will find that the sequence timecode will not match.

This tells me that this removes the Kona drivers and storage from culpability, and that the problem is probably in QT or FCP. For best results in seeing this, use a 6-minute sequence.

System Stats:
PowerMac Quad G5 w/7800
4.5GBs of RAM
Kona LHe



Jeff Bernstein

Digital Desktop Consulting
Apple Pro Video VAR
XSAN Certified

323-653-7611


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Jeff Bernstein
Re: 720P 10-Bit Reality Check
on Oct 3, 2006 at 7:04:13 am

More tech specs:

FCP 5.1.2
OS 10.4.7
QT 7.1.3
Kona LHe 3.1



Jeff Bernstein

Digital Desktop Consulting
Apple Pro Video VAR
XSAN Certified

323-653-7611


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gary adcock
Re: 720P 10-Bit Reality Check
on Oct 3, 2006 at 1:35:01 pm

[Jeff Bernstein] " Interestingly, we can get the first frame of video to consistently layoff, but after a few minutes of running time, the timeline starts to first slip by 1 frame, then a couple of minutes later, 2 frames, etc."

hey Jeff
because there is no drop frame in 24p, and if the tape was pre-striped with Black you may see this happen.

the numbering is too close to DF/ NDF issues.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows


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Jeff Bernstein
Re: 720P 10-Bit Reality Check
on Oct 3, 2006 at 4:44:43 pm

Hi Gary,

The sequence was 59.94 non-drop. We were also using a Black and Coded tape.

Though, if it is a drop to non-drop issue, won't you see 2 frame increments instead of one? The thing that really makes this a mystery is when we take the deck out of the equation and export a QT Reference or Self-Contained Movie.

Jeff

Jeff Bernstein

Digital Desktop Consulting
Apple Pro Video VAR
XSAN Certified

323-653-7611


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gary adcock
Re: 720P 10-Bit Reality Check
on Oct 4, 2006 at 12:24:27 am

[Jeff Bernstein] "We were also using a Black and Coded tape. Though, if it is a drop to non-drop issue, won't you see 2 frame increments instead of one? "

I will bet you a drink at DV expo that the Precoded/ Black on tape is the culprit.
and the file is 2 framesoff because the file is 59.94 and the tape was coded at 29.97???

just a guess.



gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows


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Jeff Bernstein
Re: 720P 10-Bit Reality Check
on Oct 4, 2006 at 8:35:57 am

I'll take that bet. Jon Thorn will officiate.


Jeff Bernstein

Digital Desktop Consulting
Apple Pro Video VAR
XSAN Certified

323-653-7611


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gary adcock
Re: 720P 10-Bit Reality Check
on Oct 4, 2006 at 1:13:48 pm

[Jeff Bernstein] "I'll take that bet. Jon Thorn will officiate."

What does he know about 720p??? (sorry JT)

HDCAM, 444,or 2K sure, but I do far more 720 than he does.
I am pretty sure that Jon will be at interbee that week.


so I will officiate on his behalf...



gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows


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Jeff Bernstein
Re: 720P 10-Bit Reality Check
on Oct 10, 2006 at 1:17:04 am

After 16 hours of testing, I have discovered the following...



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