HPX250: Issues removing pulldown from 24-over-60 SDI signal using Decimator MD-HX

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danwinckler

New member
Hi everyone. I am attempting to remove pulldown from a 23.98p signal (reverse telecine), sent via SDI from an HPX250 (recording AVC-Intra 50 1080p23.98), using a Decimator MD-HX scaler. The scaler is set to output 1080p23.98, but it is somehow failing to do the pulldown. The output of the Decimator is going to a Blackmagic capture device (UltraStudio Mini Recorder) connected to a MacBook Pro. I have done multiple capture tests using Blackmagic Media Express, and in every instance the recording shows ghostly frames for the repeated 3:2 pulldown frames instead of the proper 23.98 frames.

The Decimator manual is slim and their support department has been unresponsive, so I'm hoping someone here has tried this particular combination and might shed some light on what is going wrong here. Any thoughts or troubleshooting help would be greatly appreciated! Many thanks.




:costumed-smiley-047
 
Yeh, most people don't know that a SDI signal is based on 60i. I've worked on several live streaming Red Carpets and the idiot director wanted 24P. Nice jumpy fast pans. Ugghh. Also, a ego tech guy couldn't get a picture from a Panny HD 1800 VTR. He said he set it up for the 24P cameras. I let him suffer 10 min. before show time and told him to set it for 60i, because that was the carrier for SDI.

Can't you just copy from the card to your editing system? That's easy. Or capture the SDI and start a project for 24P in the editing software. It should do the pulldown for you, at least it does in my GrassValley Edius.
 
Sorry, I should have given more information. It is for a live webcast. The actual signal flow is two cameras to an ATEM switcher and out to an Atomos Ninja Blade program recorder and the Blackmagic USMR for the webcast. I've tried it with the Decimators before the switcher and after -- in both cases the pulldown isn't getting properly removed and the 'ghost' frames are visible on the stream and the program recording.
 
Have you tried to change the frame rate to 24F on the encoder? That might help. One time the location we streamed from could barely make 600bps up. We set the encoder, Adobe Live Encoder in this case, to 20fps. I still looked good because it was mostly talking heads. I think the frame size was 640X360. Pretty nice pic. All encoders have options for frame rates. I don't know why you would use 24P anyway unless you had poor pushes. Good luck if you have any action shots.

As for recording, just record, and later when you go to edit, just edit in a 24P timeline, project. But in todays tech world, internet speed is much higher than when I was streaming 5 years ago. Don't need 24P.
 
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Thanks, Johnny. The Ninja Blade and the USMR are set to 23.98p. For aesthetic reasons, we stream at 24p or 30p, depending on the content. It's mainly academic conferences or performances, so we don't see much fast action with judder issues.

If anyone has experience removing the pulldown from 60i SDI signals from Panasonic cams, with the Decimator or other frame rate converters, please do tell.
 
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