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Duplicated frames, jerky motion

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Zach Worden
Duplicated frames, jerky motion
on Aug 3, 2015 at 1:37:02 pm

I have some HDV footage that was shot at a slow shutter speed in low light. In a 60i project, every frame repeats once. It needs to end up in a 24p project, but when I bring it into that project there is no pattern to the repeated frames and the motion is really jerky. Any ideas on potential fixes would be greatly appreciated.

Zach


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Michael Phillips
Re: Duplicated frames, jerky motion
on Aug 3, 2015 at 5:43:08 pm

Can it be slow motion, or does it have to be "at speed"?

Michael


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Zach Worden
Re: Duplicated frames, jerky motion
on Aug 3, 2015 at 5:48:28 pm

Some of the shots could be slowed down a little bit.

Zach


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Michael Phillips
Re: Duplicated frames, jerky motion
on Aug 3, 2015 at 7:07:02 pm

I am assuming it was shot interlace? So there are 59.94 fields of motion every second? Or was it shot progressive at either 29.97p or 59.94p. This changes the way one might approach the problem. At the end of the say, it will either be a frame for frame slomo - which means no artifacts but everything is slower, or frame rate manipulation to create 23.976 progressive frames from 59.94 fields or frames.


Michael


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Zach Worden
Re: Duplicated frames, jerky motion
on Aug 3, 2015 at 7:10:27 pm

I'm pretty sure it was shot interlaced.

Zach


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Michael Phillips
Re: Duplicated frames, jerky motion
on Aug 3, 2015 at 9:41:37 pm

OK - you have a lot of issues fighting you for quality here.

1. Slow shutter creates more movement within the field/frame that a faster/higher shutter speed
2. Interlace also has motion in one half the frame (odd lines) and different motion in the second half the frame (even fields)
3. With interlace, you have one set of motion that is half the horizontal resolution of the format being shot. For example an interlace frame of 1080 HD is actually made up of two fields of 1920x540.

This is where hardware-based convertors earn their reputation for higher quality as they do a lot of motion estimation and such when doing conversions.

You can get pretty good quality with software conversions - Twixtor has a good reputation and can be used as a free trial (watermarked).

You can try different motion adapters in Media Composer for different quality, but due to the above 3 bullet points it will not be great.

If you can get away with slomo (20%), then you can deinterlace, have 29.97p frames, then play that back as 23.976 frame for frame.


Michael


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Shane Ross
Re: Duplicated frames, jerky motion
on Aug 3, 2015 at 10:12:38 pm

What camera? Because early SOny HDV cameras had a "cine mode" that was horrid. It faked the film look by shooting 30fps...interlaced...but repeated frames. So it was 15fps, with duplicated frames. HORRBLE, I say.

Sounds like that's what's happening here.

Shane
Little Frog Post
Read my blog, Little Frog in High Def


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Zach Worden
Re: Duplicated frames, jerky motion
on Aug 4, 2015 at 3:42:31 pm

Most of the film was shot on a Sony HVR-Z1U, including these problematic shots, I believe. While most of the film was shot in Cineframe 24, I believe these shots were recorded in regular 1080i60 in order to slow the shutter enough to get an image in low light. Maybe that's bad info though, since this sounds like a Cineframe issue to you.

Zach


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Zach Worden
Re: Duplicated frames, jerky motion
on Aug 4, 2015 at 3:33:30 pm

Thanks Michael. I'll give Twixtor a try.

Zach


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Robert Ober
Re: Duplicated frames, jerky motion
on Aug 3, 2015 at 10:42:27 pm

[Zach Worden] "I'm pretty sure it was shot interlaced."

Drag a clip to Mediainfo and see what it says.

Robert


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Zach Worden
Re: Duplicated frames, jerky motion
on Aug 4, 2015 at 3:29:10 pm

Thanks. Here's what I got from Mediainfo:



Zach


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Michael Phillips
Re: Duplicated frames, jerky motion
on Aug 4, 2015 at 3:32:32 pm

Interesting frame size - if you are willing to send me a sample, I will take a look at it in Media Composer and try some different frame rate conversions for you. use wetransfer.com or filemail.com to send to: michael[at]24p[dot]com


Michael


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Michael Phillips
Re: Duplicated frames, jerky motion
on Aug 4, 2015 at 3:55:41 pm

Doing some research into the archives of different forums, I came across the following from Adam Wilt. So regardless of what solution you find, it will never be clean and will always include some frame blending.

Michael



Cutting to the chase: CF24 cherry-picks fields from the camera's 60i video stream to simulate the juddery motion of 24p. However, the motion is worse (more uneven, more syncopated) than true 24p imagery, and it cannot be reverse-telecined to get smooth 24fps imagery. CF24 is fine as a special effect if you're staying on video at 60i, but it's not suitable for a true 24fps feel, nor will it work for film-outs: the motion is too unsmooth, and the vertical resolution of the image is damaged. For film-outs, shoot at 60i and use a program like DVFilm's Maker or your film-out facility's own in-house process to convert 60i to 24p.

Cineframe 24 appears to be mixing and matching a witches' brew of field-doubled, frame-based, and synthesized images in its five frame cycle.


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Zach Worden
Re: Duplicated frames, jerky motion
on Aug 4, 2015 at 4:07:15 pm

I sent a sample using wetransfer.com. Thanks!

Zach


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Michael Phillips
Re: Duplicated frames, jerky motion
on Aug 4, 2015 at 4:12:36 pm

got it. Will take a look at it later this afternoon when I get the time. Stay tuned.

Michael


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Shane Ross
Re: Duplicated frames, jerky motion
on Aug 4, 2015 at 5:00:21 pm

Can you send it my way too? comeback at mac dot com. I had to cut a pilot with footage shot in Cineframe and know it too damn well.

Shane
Little Frog Post
Read my blog, Little Frog in High Def


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Zach Worden
Re: Duplicated frames, jerky motion
on Aug 4, 2015 at 6:31:09 pm

I just sent you a clip, Shane. Thanks so much!

Zach


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Shane Ross
Re: Duplicated frames, jerky motion
on Aug 4, 2015 at 6:54:03 pm

Yup, that's exactly what that is...60i shot in Cineframe where it basically shoots 30p...but with repeat frames. So it's really 15fps. Trying to get this to look good in a 24p sequence...that'll be rough. Twixtor and AE might be the only route with this footage.

When I had to deal with it my frame rate was 29.97, so it wasn't too bad. Still looked stuttery, and we did chew out the "DP" who said "I thought you wanted the film look" without researching what that mode really looked like.

Shane
Little Frog Post
Read my blog, Little Frog in High Def


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Michael Phillips
Re: Duplicated frames, jerky motion
on Aug 4, 2015 at 7:00:44 pm

Yes, 30p (29.97p) is about the worse scenario you can have going to 23.976p. For some stuff, you can remove the redundant frames, then play back the resulting frames at 23.976 which will change its speed, but offer the best image quality as nothing got blended.


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Zach Worden
Re: Duplicated frames, jerky motion
on Aug 6, 2015 at 4:04:29 pm

I'll give that a try. Thanks, Michael.

Zach


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Zach Worden
Re: Duplicated frames, jerky motion
on Aug 17, 2015 at 2:47:32 pm

Thanks everybody for your help on this. I was able to remove the duplicate frames in a sequence in the 30fps project and then open that sequence in the 24fps project where I retimed it in Twixtor to bring it back to the correct duration and speed. It looks pretty good.

Zach


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Zach Worden
Re: Duplicated frames, jerky motion
on Aug 6, 2015 at 4:02:39 pm

Thanks, Shane. I messed around with Twixtor a bit with no success. Any idea what settings might work?

Zach


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Shane Ross
Re: Duplicated frames, jerky motion
on Aug 6, 2015 at 5:05:11 pm

Sorry, I don't know. it was on a work machine years ago...I haven't had the need for it so I don't own it.

Shane
Little Frog Post
Read my blog, Little Frog in High Def


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