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Interlaced lines problem exporting from Avid MC (MAC)


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#1 JD Marlow

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Posted 23 April 2008 - 08:49 AM

Hi,

I've been desperately trying to export from Avid Media Composer a Beta SP capture quality (2:1) of my telecined 35mm film project. I'm working on a 23.976 timeline meant for going back to neg cut and print. But I'm simply trying to create a basic "Screener" copy of the film before I go back and telecine to an HD format.

However, every time I export from the timeline SAME AS SOURCE and play on my DVD player (it's progressive scan) I get horrible motion artifacts all over the place sourcing from interlaced lines. It was suggested to me that I export LOWER FIELD FIRST, but there is no option for that, as the video is not in 29.97. It's natively progressive at 23.976 on the timeline, and I believe it's the source of the problem here...although I could be wrong about that. There must be a way to export 23.976 progressive SAME AS SOURCE in this way and not have this problem with interlaced lines and motion artifacts...does anyone have an idea?

-JD
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#2 Michael Nash

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Posted 23 April 2008 - 03:09 PM

This is a little out my territory, but could it be a problem with the authoring of the DVD? Be sure that you're creating a true 24P DVD and not a 60i.
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#3 JD Marlow

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Posted 23 April 2008 - 11:32 PM

This is a little out my territory, but could it be a problem with the authoring of the DVD? Be sure that you're creating a true 24P DVD and not a 60i.


I think that is part of the problem. I'm trying to export a Progressive, natively 23.976 fps Quicktime file from the Avid Timeline, then compress to MPEG-2 progressive as well. But even using those settings in Compressor gives me, what DVD Studio Pro thinks is a 29.97 file. What I'm really looking for is a solution to the MPEG-2 believing this is 29.97 interlaced video, because it's not. That, I believe, is where this motion jittering is coming from on the progressive scan DVD player...

-JD
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#4 Steve Wallace

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Posted 24 April 2008 - 03:01 PM

I had the same problem with a 29.97 d-beta export to DVD. I finally ended up deinerlacing the DVD using motion estimation in compressor (final cut studio). I know it may not have been the best solution, but I have a deinterlaced screener and an interlaced d-beta master.
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#5 Michael Nash

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Posted 24 April 2008 - 04:19 PM

I had the same problem with a 29.97 d-beta export to DVD. I finally ended up deinerlacing the DVD using motion estimation in compressor (final cut studio). I know it may not have been the best solution, but I have a deinterlaced screener and an interlaced d-beta master.


If you're showing 60i material on a progressive scan monitor, won't you always have interlace artifacts? Can you even burn a DVD as 29.97 "P"?
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#6 John Sprung

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Posted 24 April 2008 - 06:32 PM

If you're showing 60i material on a progressive scan monitor, won't you always have interlace artifacts? Can you even burn a DVD as 29.97 "P"?

If something was shot 60i, it'll always have interlace artifacts no matter what you show it on. The defect is in the image capture. You should be able to get HD-DVD to do progressive, but plain old DVD is always NTSC or PAL, therefore interlaced. There are upconverting DVD players that can output 720p or 1080i, but from existing SD disks.

TV shows routinely shoot 24p and output SD DVD's from their Avids for the producers, exec's and network. If an assistant editor ran into this problem, what they'd do is phone up the Avid rental place and get talked through all the settings and mouse clicks.



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#7 Michael Nash

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Posted 24 April 2008 - 07:09 PM

but plain old DVD is always NTSC or PAL, therefore interlaced.


I thought SD DVD's could be either 24P or 60i. 24P on DVD may be stored as 24PsF and re-interleaved on playback for all I know, but isn't it still 24 complete frames without pulldown, not 60i NTSC? The DVD player inserts the proper 3:2 pulldown for display on a 60i display, or de-interlaces 60i material for progressive display (if selected), right?

I've created 24P timelines and had to encode it as such with Compressor for the DVD to play properly on both a computer and a standard NTSC player & TV. Otherwise, you turn your 24P into 60i with pulldown and output it that way. Similarly, DVD's of feature films usually play back with a 1:1 frame ratio and no interlace artifacts on my computer, while other DVD's of film material stored as 60i clearly exhibit pulldown and interlace artifacts.
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#8 John Sprung

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Posted 25 April 2008 - 05:32 PM

24P on DVD may be stored as 24PsF and re-interleaved on playback for all I know, but isn't it still 24 complete frames without pulldown, not 60i NTSC? The DVD player inserts the proper 3:2 pulldown for display on a 60i display, or de-interlaces 60i material for progressive display (if selected), right?

What's actually on the disk is MPEG-2 data. The encoding software is plenty smart enough to take advantage of coherent film frames and drop redundant third fields from 3-2, so in that sense you're right that film originated material is kinda in 24p form on the disk. But it is resolution limited to work on interlaced displays, it has about 65% of the resolution of a true progressive picture.

Conventional DVD players output NTSC or PAL, it's only the upconverting ones that have progressive outputs. I got one of those about 2 1/2 years ago, along with a CRT HD set. DVD movies do look a lot better on that setup, but I think it's mostly the finer display structure. That upconverting player is a transitional product, they'll disappear as real HD players take over.




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#9 Steve Wallace

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Posted 26 April 2008 - 03:12 AM

If you're showing 60i material on a progressive scan monitor, won't you always have interlace artifacts? Can you even burn a DVD as 29.97 "P"?


I was watcing on a normal tube TV too. It was when I encoded to DVD, I got jaggies / wavies from the interlacing.

But when I gave the tape dup house my interlaced file 720 x 486, 29.97fps lower field dominance, black magic 10bit uncomressed it played perfectly on the d-beta desk. Thats what I don't get ... why can't my interlaced DVD play without problems, but my interlaced d-beta is fine. I tried compressor and ffmpegx to encode, until i gave up and deinterlaced. Which turned out fine more or less. But obviously the d-beta looks way better.

There is no 29.97 "P" ... by nature it is "i"

I thought SD DVD's could be either 24P or 60i. 24P on DVD may be stored as 24PsF and re-interleaved on playback for all I know, but isn't it still 24 complete frames without pulldown, not 60i NTSC? The DVD player inserts the proper 3:2 pulldown for display on a 60i display, or de-interlaces 60i material for progressive display (if selected), right?


As far as I know, that is correct. 24P DVDs the player adds the 3:2, 29.97 DVDs the 3:2 was added in the telecine stage (or software etc...) ?

My timeline was 29.97, and the field dominance was always set to lower? I didn't use a 24P timeline because my telecine was 29.97.

Edited by Steve Wallace, 26 April 2008 - 03:14 AM.

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#10 JD Marlow

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Posted 27 April 2008 - 11:10 AM

Hi,

It looks like the problem from my original question was the pullin from original capture. I had a mask covering the keycode on my source footage, but when I looked back on it I was getting: A, B, B, D -- instead of the correct A, B, C, D that denotes a correct pullin. The deck I used to capture all my source footage, as it turns out, is very old and does a poor job of capturing on the correct pullin frame.

It look 4 hours to re-batch capture and export but my footage finally looks normal upon a SAME AS SOURCE export. Thanks for your help everyone! I hope others can learn from my mistake.

-JD

P.S. For proper DVD export I conformed the 24 fps quicktime file to 23.98 using Cinema Tools, then encoded to MPEG-2 in Compressor on a 23.98 progressive setting. Plays perfectly on my progressive scan DVD player.
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