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Tiny lines, quicktime motion artifact in reference movies

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Mary Haverstick
Tiny lines, quicktime motion artifact in reference movies
on Feb 21, 2011 at 7:38:33 pm

Hi all,
I am finally posting a LONGTIME question/problem I have been struggling with to no avail... This issue has come up for YEARS and seems to be present to some degree no matter what footage framerate or origination format I use and what end product compression or encoding setting I use, I just can't seem to eliminate it, only try and minimize... HERE GOES...
Whenever I output a project from my avid (Adrenaline, Mac: has happened on different macs, OSs and Media Composer and Qtime versions) and I go to a Quicktime Reference movie from which I encode to DVD (using either Sorenson, Encore, Studio Pro, or any of them) I find that during motion my quicktime reference movie, or any quicktime I output whatsoever takes the area of the frame which is in motion and creates this little line pattern at a much thicker line screen resolution that the rest of the image, and it ONLY does it in the patch of the frame which is moving, and ONLY when the motion exceeds a certain amount.
If it is a talking head, it will all seem good until a hand movement or speech moment when all of a sudden the lips go to these little striations, little lines which are clearly not as good a resolution as the original. When I stop on a frame of my Qtime reference movie and compare to the frame in my AVID, it is clear that this is introduced at the quicktime level and is not on my original. The concern is this just gets passed along to next generations be it web movies or DVDs and while many times it falls in the acceptable range it is ANNOYING AS ALL GET OUT!!! And sometimes, depending on field orders, settings etc it gets worse and becomes at or near the unacceptable range. It often takes much working around to find the best settings.
I have experimented with ridding myself of this plague for more hours than I ever want to admit here, but let me just say that I have had the issue present no matter what quicktime settings I use, or so it seems. It certainly has seemed to me to be an issue of field processing... I have had this issue when the base footage was old mini DV all the way up to lovely HiDef footage, and at seemingly all framerate combos. I really am not sure I have ever seen a setting combination that has rid this completely.
If someone solves this for me, they will give me back many future hours of my life, that I would otherwise be spending once again trial and erroring my settings. Solutions and workarounds are greatly appreciated!
Best,
Mary



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Daniel Ludwig
Re: Tiny lines, quicktime motion artifact in reference movies
on Feb 23, 2011 at 9:29:43 am

hi mary,
this is 100% OK, because I guess you are working with interlaced material.

AVID maybe wont output the fields, so you will see only one field progressivly - but there are two fields, so your quicktime-file is really fine.

if you are bothering with quicktime, you can turn on the deinterlacing quicktime-output.

to do so you need to open your video within quicktime and turn cmd-j (on mac) on pc it might be ctrl-j.

then select video track, select your visual settings and check the deinterlace-checkbox.

right now you wont see the interlaced-artefacts anymore, and then save your quicktime-file.

NOTE: if you give this filme to someone else for broadcast for example, the deinterlacer needs to be off, otherwise there could be problems with your film.

cheers

danny


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Mary Haverstick
Re: Tiny lines, quicktime motion artifact in reference movies
on Feb 23, 2011 at 5:49:21 pm

Thank you Danny,
this is so helpful.
I have one more question tho, if I am to use this reference movie to then encode to DVD do you recommend me using the quicktime interlace setting on or off for best results? It seems to me when I watch my encoded DVDs from these reference movies that I sense the lines issue on moving sections, but I am not certain if it is that or other compression issues.
let me know on that setting, and you are a champ!
Mary


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Daniel Ludwig
Re: Tiny lines, quicktime motion artifact in reference movies
on Feb 23, 2011 at 6:18:22 pm

mary,
of course you need to have interlaced material for your encoding - if the orignal have been interlaced material, too.

there could be more than one issue, why you might see lines on screen. you have to be carefully while setting up your encoder - never use automatic field-detection, they could fail.

and you might thing about downscaling your HD-material before you start encoding.

cheers

danny


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Bill Stephan
Re: Tiny lines, quicktime motion artifact in reference movies
on Feb 23, 2011 at 5:26:24 pm

On Avid editing systems, you see only one field when you pause playback of footage. On Final Cut Pro systems you see both fields when you pause footage. Both systems are working correctly. As an editor, you need to be aware of what your edit system is showing you.

The interlacing artifacts you see are the nature of all interlaced video standards. If you play your footage out to a picture monitor capable of dealing with interlaced signals, then there is no problem. You should be able to do a quality DVD encode from interlaced footage. We work from every video standard and frame rate, and we don't get artifacts in our encodes.

All the fun begins when you need to take interlaced footage and do something such as rotoscoping or other effects work. Or when you prepare interlaced footage for use in a progressive medium such as a web site, then you need to deal with the interlacing issues.

Bill Stephan
Senior Editor/DVD Author
USA Studios
New York City


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Mary Haverstick
Re: Tiny lines, quicktime motion artifact in reference movies
on Feb 23, 2011 at 5:58:03 pm

Bill,
Thank you so much. You are right, it seems I should have known how my AVID displays fields, I assumed it was showing both together in some sort of composited way. Of course I have run into the many mysterious ways fields create issues in special effects, tracking etc., and am hoping by demystifying and understanding them better I will improve results.
Thanks so much for your help!
Mary


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