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Bob Cole
sync
on Dec 11, 2010 at 6:16:59 pm

I'm seeing sync issues in FCP and would appreciate help in narrowing down the cause.

Video is lagging. I've tried outputting both to SD and HD monitors (component both), and results are similar. When I stop playback the video "catches up" by jumping forward several frames. The sync seems to get worse the longer I play the video.

My CalDigit HDOne had less than a terabyte free before I deleted a lot of files recently; now it has about 2.5 tb free. I use an AJA Kona LHe card.

The AJA system test, on one of the same files with the sync issues, gives 443 MB/s.

When I convert the files from HD (1920x1080) to SD, they play in sync.

Suggestions on where to start?

Mac Pro, dual core, Snow Leopard, CalDigit HDOne.

Bob Cole


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gary adcock
Re: sync
on Dec 12, 2010 at 5:33:34 pm

[Bob Cole] " The sync seems to get worse the longer I play the video.
"


believe it or not it is usually an audio issue, not a video one-

mixdown and re-render your audio

use slugs rather than blank spaces when you want black- these gaps will cause the audio to jump.

turn off RT extreme and render the file out prior to playout.

gary adcock
Studio37

Post and Production Workflow Consultant
Production and Post Stereographer
Chicago, IL

http://blogs.creativecow.net/24640



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Bob Cole
Re: sync
on Dec 12, 2010 at 6:15:05 pm

Thanks Gary.

I found the solution, and it was User Error. But I want to use this as a learning opportunity. re the audio mixdown, I should have added: these are freshly-transferred files thaI have just laid down on a timeline. No edits.

The solution was to change FCP Video Playback from AJA Kona 1080i 29.97 (10-bit) to (8-bit).

The Learning Opportunity question: does this indicate some defect in my computer? Should my MacPro be able to handle 10-bit? I don't really have a need for 10-bit timelines, afaik.

Thanks again Gary! You helped me find the answer -- I don't know exactly how, but you did.

Bob C.


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jason levy
I have the same problem. See thread below.
on Dec 12, 2010 at 7:43:53 pm

Holy cow. If it wasn't snowing heavy I'd head over to the office now and check that setting. I'll have a look at that in the morning.

jason



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jason levy
Re: I have the same problem. See thread below.
on Dec 15, 2010 at 4:43:49 pm

Yes, that solved my problem to. What is odd is that the editor tells me he's been using that 10 bit setting for a long time with out problems. I'm a bit confused as I thought ProRes was a 10 bit codec.

jason



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Jeremy Garchow
Re: I have the same problem. See thread below.
on Dec 15, 2010 at 4:44:40 pm

[jason levy] "I'm a bit confused as I thought ProRes was a 10 bit codec."

It is.


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jason levy
Re: I have the same problem. See thread below.
on Dec 15, 2010 at 8:21:45 pm

Ahem. So then I said to myself, "Self, why is 10 bit playback no longer functioning?"



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Jeremy Garchow
Re: I have the same problem. See thread below.
on Dec 15, 2010 at 8:22:37 pm

[jason levy] "Ahem. So then I said to myself, "Self, why is 10 bit playback no longer functioning?""

I'm not sure, exactly. It seems there's a mismatch of settings somewhere.

Jeremy


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Jeremy Garchow
Re: sync
on Dec 13, 2010 at 9:33:59 pm

[Bob Cole] "The solution was to change FCP Video Playback from AJA Kona 1080i 29.97 (10-bit) to (8-bit).

The Learning Opportunity question: does this indicate some defect in my computer?"


What codec is your timeline?


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Bob Cole
Re: sync
on Dec 18, 2010 at 1:11:24 pm

Good question, Jeremy. I apologize for not responding earlier. I had to go on the road for some shoots.

I assume (from trying to retrace my steps) that the original timeline codec was Apple ProRes422; the "Video Processing" tab reads "Render 10-bit material in high-precision YUV."

When I apply Apple ProRes422 (standard, unspecified version), in Audio/Video Settings, the Video Playback is listed as AJA Kona LH 1080i29.97 10 Bit (1920 x 1080). When I change this setting to 8 Bit, my problems with display on the external monitors (both SD and HD) go away.

So now I see what you say about ProRes = 10 Bit. I hope my solution (change Video Playback to 8 Bit) is valid. What say you? Does this indicate a problem that I can't detect otherwise, and if so where is the problem -- with the AJA card? All the speed tests I can run on my CalDigit HDOne seem to be fine, but even there, the graph shows some spikes downward in an otherwise high speed rating.

Bob C


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gary adcock
Re: sync
on Dec 18, 2010 at 2:17:57 pm

[Bob Cole] "When I apply Apple ProRes422 (standard, unspecified version), in Audio/Video Settings, the Video Playback is listed as AJA Kona LH 1080i29.97 10 Bit (1920 x 1080). When I change this setting to 8 Bit, my problems with display on the external monitors (both SD and HD) go away."

Bob

you do not mention what is your original material and how was it captured or more likely converted to ProRes.

See you're starting with 8 bit materials and working in Standard PR content that is NOT going to force a 10bit space unless you added something ( filters or effects) to the mix to force the files to re-render. If you are working with a minimal cuts only project I have seen this issue with only the 8bit output not being affected.

gary adcock
Studio37

Post and Production Workflow Consultant
Production and Post Stereographer
Chicago, IL

http://blogs.creativecow.net/24640



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