horizontal jitter in footage during movement

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pdsage10

Well-known member
I shot some footage at 720 24p on the HVX. I am using Avid Media Composer to edit and have not transcoded the mxf files. They play back fine, except for the ones that have panning in them. These shots almost look like the interlacing is not matching up. There are single frame horizontal seperations in the picture during play back, but when I go back and look at the footage frame by frame, the seperations are not there. The shots that look bad are the ones when the camera is panning during a dolly shot. I have also sent a Quiktime Ref. file out to After Effects and interpolated the footage to get a progressive image, but during playback the seperation is still there( but not if veiwed frame by frame). Does anyone know what could be causing this? Thanks
 
There could be more to it, but when shooting Progressive and 24fps, you can expect that on pans and fast movement.
There threads on calculating panning speed.
If you only see it on pans and dollys, this could be the problem.
 
I was just going through some other footage and its even in a shot that is static, but there is a large object moving through the frame. On the edges of the object there are a few random horizontal seperations that only last for a split second each. Why would this occur only during playback and not when I go back to look at it frame by frame?
 
It could be your video card. I know that on my 23" Apple Displays, that I get that the same thing, becasue my video card is not higher.
 
I have an Nvidia with 512mb video memory. If it is the video card just not displaying correctly, would my final output not have these seperations in it? I did a down rez. sequence of the footage in After Effects (720/480 23.976) and it still plays back with the seperations.
 
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It's not a video card problem, all video cards and computer displays are progressive. I suspect that Avid is interlacing the video, possibly due to incorrect project settings.
 
How could it be the project settings? It is interlaced footage from the HVX 720 24p (in interlaced wraper). Im editing it on a 720 59.96 project time line, so it should play back correctly. Or am I missing something here?
 
If the footage was shot in 720/24p it is progressive. There is no 720 interlaced wrapper. That happens only in 1080. Was it shot in 720/24p or 720/24pn?
 
pdsage10 said:
It was shot in 720 24p not 24pn. Doesnt that mean that there is an interlaced wraper?
Click to expand...

No, it was shot progressive. It does mean that there were 60FPS recorded though, so you will need to remove the redundant frames on import into your NLE. Also make your timeline setting 23.98. When you step through frame by frame and everything looks ok, count how many framers you are seeing in a second.
 
Ok, that makes sense, but then why would the playback still have horizontal seperations in After Effects after I have interpolated the footage(removed pulldown)?
 
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I don't know for sure, but if you didn't remove the pulldown properly AE would probably blend frames together which could create some ghosting/double images...
 
I'm not familiar with how the avid handles the MXF files but I think your setting of 59.94 are wrong. Did you make a new sequence and change the settings from 59.94 to 23.98?
You also stated in your first post that you are playing the MXF files. I think you would need to import these and remove the redundant frames. Did you do a count while stepping through frame by frame and count how many frames you have in a second of footage? That should tell you if you have removed the redundant frames.
 
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