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Jittery footage (field flicker?)
I’ve got an NTSC Standard project with footage from the past few years captured from tape (720×486, lower field first). I’ve added some new NTSC DV (720×480) footage shot with my HVX200 from P2. All the footage from tape looks perfect when it plays, and all the stuff from the HVX has awful field stuttering. I looked and saw that the HVX footage is “upper field first”, so I switched them to “lower”, and there’s no change at all.
The only thing that smoothes out the offending footage is to check “Reduce interlace flicker”, but that then makes everything look a little bit soft.
Why wouldn’t switching field order from “upper” to “lower” fix it by itself?
Also, if someone knows if it would be a good idea or bad idea to switch the HVX to record “lower field first” (and how to do that), I’d love to know.
Thank you!
–Kelly
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3 Replies
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[Kelly Griffin] “I’ve added some new NTSC DV (720×480) footage shot with my HVX200 from P2. All the footage from tape looks perfect when it plays, and all the stuff from the HVX has awful field stuttering. I looked and saw that the HVX footage is “upper field first”, so I switched them to “lower”, and there’s no change at all.”
If you really recorded in DV mode the footage should be lower field first. I would use a tool like MediaInfo on the original file to see if it was recorded correctly. If it’s lower filed first and Vegas thinks it’s upper field first that may be whetre the problem lies. Changing this on the media tab should have fixed the problem but you said you did that and it didn’t. This is very strange.
[Kelly Griffin] “Also, if someone knows if it would be a good idea or bad idea to switch the HVX to record “lower field first” (and how to do that), I’d love to know.”
It should be doing this when it’s recording in DV mode. That’s why it’s good to check the files from the camera with MediaInfo to see what they really are.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
John– I just realized something else… In my project properties, I’ve been leaving “Deinterlace method” to “None”, and I think I remember one of your comments from way back that this should essentially always (?) be set to “Blend fields”.
I did, and that fixed it. Is that true that I should just do that for any interlaced footage? And, if so, why is the default “None”, and is there a way to set it and forget it in the properties list?
–Kelly
ps: I guess I also don’t really understand what blending fields and interpolating fields is doing, and why, if it’s a lower-field-first project, the fields need something done with them in the first place to make them do what they’re supposed to do (and have always done fine for years with other programs).
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[Kelly Griffin] “John– I just realized something else… In my project properties, I’ve been leaving “Deinterlace method” to “None”, and I think I remember one of your comments from way back that this should essentially always (?) be set to “Blend fields”.”
That would do it! 🙂
Actually, my comment was that under normal circumstances it should never be set to None. Blend Fields is the default and Interpolate Fields is the other options (more about that later)
Technically, there are reasons to use None. If you are using your own deinterlacer like BCC DeInterlace or if you have all progressive footage. But even if you have all progressive footage, you can still leave it a Blend Fields and it won’t hurt anything. So the only real reason to use None is to use your own deinterlacer.
[Kelly Griffin] “I did, and that fixed it. Is that true that I should just do that for any interlaced footage? And, if so, why is the default “None”, and is there a way to set it and forget it in the properties list?”
The default is Blend Fields. If I install Vegas Pro 11 fresh, this is the default that I get. If you want to make sure that yours is always set to Blend Fields, you need to check the box that says “[x] Start all new projects with these settings”
[Kelly Griffin] “ps: I guess I also don’t really understand what blending fields and interpolating fields is doing”
The difference is:
Blend Fields will take the information from both fields and blend them together into a single frame. This works with interlaced footage that has low motion.
Interpolate Fields make no attempt to blend anything and simply throws one of the fields away and doubles the other field to maintain vertical resolution. You actually loose half of your resolution but it may be the only choice with deinterlacing footage that has high motion and the fields are just too far apart in time.
[Kelly Griffin] “…and why, if it’s a lower-field-first project, the fields need something done with them in the first place to make them do what they’re supposed to do (and have always done fine for years with other programs).”
Because some processing like cropping in or out must be performed on full frames and therefore interlaced footage needs to be deinterlaced before it can be resized and then re-interlaced. Otherwise you would resize the individual fields and make an ugly comb effect.
~jr
http://www.johnrofrano.com
http://www.vasst.com
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