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IO HD suspected to be introducing junk frames into pulldown

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Jared Lorenz
IO HD suspected to be introducing junk frames into pulldown
on Dec 17, 2008 at 2:21:36 am

We are outputting a show to HDCam from a ProRes 422 HQ 1080psf23.98 sequence.

FCP 6.05 with IO HD 6.02 on a Mac Pro running OS 10.5.5.

All goes well, then 'blip' we get junk frames in the 3:2 pulldown.

It is not in the FCP sequence or in the rendered 23.98 movie, just in the pulldown. The artifacts appear direct to monitor from the IO or played through the HDW-M2000 deck.

This primarily happens in graphics and stock that has been conformed or retimed from 29.97 to 23.98, but it also appears to happen close to cut points in footage that is natively 23.98. Irritatingly, a second episode of the same series exhibits no artifacting on exactly the same clip.

This is early in the process of troubleshooting so notes from anyone else who has experienced similar issues would be appreciated.



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Jeremy Garchow
Re: IO HD suspected to be introducing junk frames into pulldown
on Dec 17, 2008 at 2:49:14 am

Please give your system specs and please double check that all of your timelines and captured footage is actually 23.98 with a field dominance of 'none' and not upper. Check the browser for your clips and also check you sequence.

Jeremy


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Jared Lorenz
Re: IO HD suspected to be introducing junk frames into pulldown
on Dec 17, 2008 at 4:32:18 am

Indeed, the field dominance on the movie (but not the sequence) was set to upper in spite of them being captured progressively.

Funny how that was fixed in the IO's software update just TODAY.

I've flipped that flag back to NONE on the movie but it still seems to be exhibiting the issue.

These were stock CG that had been conformed, so as a workaround we applied a flicker filter (max), then rendered the clips out at 75% speed with frame blending, then brought them back up and sped them back up to full speed, in hopes that this would mask any artifacts in the original conform that might be tripping up the pulldown insertion on the IO. It pretty much fixed it but there is a lingering issue on one field.

Tomorrow we'll try recapturing the tapes with the firmware/driver updated, and see how it goes.



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gary adcock
Re: IO HD suspected to be introducing junk frames into pulldown
on Dec 17, 2008 at 2:06:18 pm

[Jared Lorenz] "Tomorrow we'll try recapturing the tapes with the firmware/driver updated, and see how it goes."

jared.

first off what machine and configuration are you using? while the IoHD handles the prores compression -the CPU/ RAM config needs to be sufficient to handle everything else.

if you are getting green flash frames to show in the pulldown you are doing the conversion in Software- Not hardware.

FYI do not add the pulldown on capture, add pulldown on playout to tape.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows

Inside look at the IoHD
http://library.creativecow.net/articles/adcock_gary/AJAIOHD.php




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Jared Lorenz
Re: IO HD suspected to be introducing junk frames into pulldown
on Dec 17, 2008 at 7:13:34 pm

FCP 6.05 on OS 10.5.5. IO HD 6.02 on an 8-core 2.8ghz Mac Pro with 10gb of RAM.

I just talked with Aja and they told me that FCP introduces the pulldown from 1080p23.98 to 1080i29.97, that the IO doesn't do it. Again, FCP inserts the 3:2 pulldown on playback, not the IO.

See below for a sample.


We are testing the non-HQ playback setting per Aja's advice to see if that helps.



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Jeremy Garchow
Re: IO HD suspected to be introducing junk frames into pulldown
on Dec 24, 2008 at 4:05:30 pm

Did this help? (hq vs non hq)?


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Jared Lorenz
Re: IO HD suspected to be introducing junk frames into pulldown
on Nov 5, 2009 at 9:41:43 pm

Sorry it took so long to respond.

Like a year.

Yes, it helped. HQ sequences should be output at HQ, same with non HQ sequences.

Jared


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