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Blocks/artefacts - where do they come from?

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Martin Langenegger
Blocks/artefacts - where do they come from?
on Jun 20, 2011 at 11:36:26 am

We got a film from a production company to use in a projection (with Watchout). The format is ProRes 422 (HQ), rendered out of Final Cut Pro. Our client is not happy with the quality and neither are we. Especially in one sequence there are blocks/artefacts (see still still frame).

The production company says that their file is in order and that they don't see any artefacts. But we see them in QuickTime and the client sees them in the Watchout projection ...

The question is: Where do these artefacts come from? And: Can they be removed? And if so, how?

Any help would be appreciated.


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Steve Eisen
Re: Blocks/artefacts - where do they come from?
on Jun 20, 2011 at 1:47:21 pm

You have to start with the original source. Just because you have a ProRes HQ file doesn't mean that it is of highest quality. HDV or any other long GOP source footage can create a lot of artifacting. Not much you can do after the fact.

Goes with the saying, Garbage in, Garbage out.

Steve Eisen
Eisen Video Productions
Vice President
Chicago Final Cut Pro Users Group


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Martin Langenegger
Re: Blocks/artefacts - where do they come from?
on Jun 20, 2011 at 4:05:45 pm

Thanks for the response. It's always good to have a second opinion.

Now we can go and try to bargain with the production company ...!


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Rafael Amador
Re: Blocks/artefacts - where do they come from?
on Jun 20, 2011 at 4:58:11 pm

[Martin Langenegger] "The production company says that their file is in order and that they don't see any artefacts. But we see them in QuickTime and the client sees them in the Watchout projection ...

The question is: Where do these artefacts come from? And: Can they be removed? And if so, how?"

Hi Martin,
Please, let be professionals. We are not judging the YouTube clips of our friend.
Without having a look to the original footage, and knowing every single detail about the systems and processes applied, nobody should dare to advance any hypothesis.
On those circumstances, the picture you linked means nothing.
the only thing we know is that you are not happy with the job, but if you want us to help you where the, artifacts comes from, please give as all the elements.
rafael

http://www.nagavideo.com


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Martin Langenegger
Re: Blocks/artefacts - where do they come from?
on Jun 20, 2011 at 6:07:10 pm

[Rafael Amador] "Please, let be professionals. We are not judging the YouTube clips of our friend."

YouTube? I don't understand what you're talking about, Rafael.

[Rafael Amador] "Without having a look to the original footage, and knowing every single detail about the systems and processes applied, nobody should dare to advance any hypothesis.
On those circumstances, the picture you linked means nothing.
the only thing we know is that you are not happy with the job, but if you want us to help you where the, artifacts comes from, please give as all the elements."


Well, I don't have the original footage and I don't no anything about the systems and processes applied - that's the problem (and it's always a problem if you're somewhere between the production company and the client). All I wanted to know is this:
- Is it possible to tell where artifacts like these come from (Camera, working in FinalCut, Output)
- Is there a way to remove these kind of artifacts digitally

Martin


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Rafael Amador
Re: Blocks/artefacts - where do they come from?
on Jun 20, 2011 at 7:02:32 pm

[Martin Langenegger] "YouTube? I don't understand what you're talking about, Rafael."
Very easy to understand: I don't gonna question a fellow Video Editor (who I don't know) with the data you show. If anybody would do that with one of my jobs, I would get very, very pissed.
I don't know which is your profession; clearly you are not a Video Editor, so if you really need professional advice because you can lose money, hire a professional.

[Martin Langenegger] "- Is it possible to tell where artifacts like these come from (Camera, working in FinalCut, Output)
- Is there a way to remove these kind of artifacts digitally"

Knowing all the info I've mentioned, and being able to reproduce the steps, shouldn't be much difficult to find out where the artifacts come from. A single value or setting wrong destroys the picture.
Cleaning artifacts is very difficult if not impossible.
Better avoid them.
rafael

http://www.nagavideo.com


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jon smitherton
Re: Blocks/artefacts - where do they come from?
on Jun 20, 2011 at 7:17:50 pm

Hi Martin

The Watchout system either uses Mpeg2, Sorenson or AVI codecs (though this may have changed - I haven't used it for 1.5 years) - both are 'Lossy' codecs and are prone to artifacts.

It could be a problem of the source (like Raphael suggests) or also could be there encoding issues.

Best to backtrack the production method -
Visit the prod co's edit suite and see if it exists there on their broadcast monitor and computer monitor. They are better to deliver an Animation codec quicktime (as this copies to Watchout on windows better) and leave the encode to the Watchout operator.

If this is fine - which the prod co's says it is - your encoding method is at fault. If using Mpeg2 or Sorenson get them to do a double pass encode. As I say, haven't used it for a while - it all should be detailed in the watchout manual of which is the better compression method.
http://www.dataton.com/watchout#

If this is multi-screen there are custom dimensions for Watchout - and the prod co should be delivering to this spec - ie a quicktime movie the size of 5192x768 for 4 screens if I remember correctly. How many screens are you doing?

Good Luck
Jon



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jon smitherton
Re: Blocks/artefacts - where do they come from?
on Jun 20, 2011 at 7:22:09 pm

ooh pays to search!
http://forums.creativecow.net/thread/2/1000639#1000645



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Martin Langenegger
Re: Blocks/artefacts - where do they come from?
on Jun 20, 2011 at 7:43:59 pm

Hi Jon

Watchout now works with H.264 QT movie files or even with ProRes Files. Our client thought it was a Watchout related problem and so thought our technicians. But we then tried to run the show with the original ProRes files we got from the production company. It did run and showed the exact same problems (blocks of pixels).

We don't normally use ProRes for Watchout because the file sizes are so large but it works if the machines are fast enough.

We at first missed the artifacts on the material because it is a fast sequence and the computer screens are so small ... Seeing it projected on the big screens makes the artifacts really pop out (those blocks are big!).

Martin


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jon smitherton
Re: Blocks/artefacts - where do they come from?
on Jun 20, 2011 at 8:53:37 pm

Ok. You still haven't said how this image was created. What camera? I have seen this type of compression artifacts with DVCPro50 cams. Is it just this shot? You need to tell us your source and whole workflow.

Jon



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Martin Langenegger
Re: Blocks/artefacts - where do they come from?
on Jun 21, 2011 at 6:50:12 am

[jon smitherton] "Ok. You still haven't said how this image was created. What camera? I have seen this type of compression artifacts with DVCPro50 cams. Is it just this shot? You need to tell us your source and whole workflow."

That's what we'd like to know too ...! The production company don't tell us. That is our problem with the workflow: Somebody films, somebody edits - we don't know how. All we get are finished files that we encode for Watchout. The client sees the final result and is not happy. The client chose the production company for the filming and us for the Watchout stuff.

It's only in this shot which is by far the most complex: fast, lots of light reflecting on the water ...

All I wanted to know is if you can tell from the kind of artifacts if it is a problem of the camera or of editing. You and Steve point to camera related problems which would mean that the client either has to accept it as it is or try to find somebody with a better camera to film it again.

Sorry, all this is difficult for me to explain in english ...


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jon smitherton
Re: Blocks/artefacts - where do they come from?
on Jun 21, 2011 at 10:28:53 am

Ok. I suspect that it is indeed the camera.
You could try denoising the shot in After Effects (reduce grain), use Neatvideo or using the Foundrys Furnace in FCP:
http://www.thefoundry.co.uk/products/furnace/
can't remember if the trial is demo with an 'X' through it or fully working.
You could try crushing the blacks to get rid of the graduation of the compression artifacts.
If the shot is slo-motion - instead of slo-moing in FCP you can get a smoother effect in Compressor using Optical Flow.

Good Luck!
Jon



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Martin Langenegger
Re: Blocks/artefacts - where do they come from?
on Jun 21, 2011 at 11:58:58 am

Thanks for the tips, Jon. I'll try that (never thought of taking the clip into After Effects for denoising - allthough I know AE much better than FCP!).

Martin


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