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what's the best codec to use to avoid "banding" during fade to black?

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Terry Coolidge
what's the best codec to use to avoid "banding" during fade to black?
on Apr 28, 2009 at 4:56:44 pm

I have a 24fps image sequence at 1024 x 768. I am using QuickTime Pro to open this sequence and export it out as a movie file with H.264 compression. My results are fantastic except for two problem areas. The very beginning where I fade up from black and again at the end when I fade out to black. The background in both instances is a soft radial gradation created by a soft spot light on a light colored background.

I chose export settings that would create a high data rate (over 10 mbits/sec), but I get noticeable circular "banding" during these two fades. Everything else is pristine. I've tried bumping the data rate up even higher, but it seems as though I've reached a limit or something, because subsequent exports are roughly the same file size and show a data rate approximately 10 mbits/sec even when I tell it to be much higher. I am doing a multi-pass compression, and I've tried forcing keyframes every 72 frames, every 24 frames, and every 12 frames.

Is there another codec I should be looking into? I thought H.264 was preferred. This movie is to be played back with QuickTime player (actually through a Keynote presentation) on a Mac. I've tried just simple Animation compression which looks flawless, but the file size is 11 GB and does chug from time to time over the course of the video's 5:15 duration. Can I find a happy medium?



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Daniel Low
Re: what's the best codec to use to avoid "banding" during fade to black?
on Apr 28, 2009 at 10:05:47 pm

The problem you are seeing is down to bad colour space conversion.

Do you have access to a dedicated encoding application like compressor or Episode or even Handbrake? - They'll all do a better job than and export out of Quicktime Pro.

If not - try exporting as PhotoJPEG at 75% or over.

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Terry Coolidge
Re: what's the best codec to use to avoid "banding" during fade to black?
on Apr 28, 2009 at 10:58:52 pm

I have Compressor. Should I just stick with H.264 for my output format and simply use Compressor instead of QuickTime Pro, or is there more to it than that?

Can I open an image sequence in Compressor, or do I need to save the image sequence in a movie format first and then pass it through Compressor? In which case would I save it as an uncompressed movie (8 bit? 10 bit?), or would it be okay to use the Animation compressed QT movie that I already have?

Thanks for the response. I appreciate being clued in to give Compressor a try.




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Daniel Low
Re: what's the best codec to use to avoid "banding" during fade to black?
on Apr 28, 2009 at 11:37:55 pm

First of all just try encoding to H.264 in compressor using the Animation movie you've already got.

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Terry Coolidge
Re: what's the best codec to use to avoid "banding" during fade to black?
on Apr 29, 2009 at 1:22:22 am

I'm not seeing any difference between the output that came out of QuickTime Pro vs. the output that Compressor was able to generate. They seem to be producing identical results (as far as I can tell).

Any other suggestions? Are there other settings I should be tweaking?

The Animation compressed QuickTime movie created with my image sequence looks smooth enough, but is there something I could have done back when I originally rendered the frames in After Effects that would be helping me out now? The color depth of my AE project was set to 8-bit. I've never messed with anything other than 8-bit. Would changing the bit depth in AE have any impact on what I'm able to achieve when doing the H.264 compression?



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Daniel Low
Re: what's the best codec to use to avoid "banding" during fade to black?
on Apr 29, 2009 at 7:12:54 am

Did you also try the PhotoJPEG codec?
It's worth mentioning that you'll see banding on even high budget DVD productions, sometimes it's unavoidable. Just how severe is it?

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Terry Coolidge
Re: what's the best codec to use to avoid "banding" during fade to black?
on Apr 29, 2009 at 4:01:23 pm

PhotoJPEG didn't appear any better.

Here are some screen shots for comparison.

http://webpages.charter.net/terrycoolidge/banding/

I'm thinking I just can't do anything about it, which seems frustrating to me.




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Daniel Low
Re: what's the best codec to use to avoid "banding" during fade to black?
on Apr 29, 2009 at 4:11:57 pm

[Terry Coolidge] "I'm thinking I just can't do anything about it, which seems frustrating to me."

Considering that it will be delivered through Keynote there's probably not anything you can do about it.

One last thing is that you could try and add a small amount of noise (or grain) to your AE Render.



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Richard Cooper
Re: what's the best codec to use to avoid "banding" during fade to black?
on Apr 29, 2009 at 7:49:26 pm

Adding a little "noise" as Terry suggests is what solves this same problem for us when we encounter "banding". It is a trade off but people will accept a little "grain" before they will accept this banding.


Richard Cooper, FrostLine

Everyone has a story to tell..... what is yours?
http://www.FrostLineProductions.com


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Daniel Low
Re: what's the best codec to use to avoid "banding" during fade to black?
on Apr 29, 2009 at 11:23:17 pm

[Richard Cooper] "Adding a little "noise" as Terry suggests"

Did he! I though that was me? ;-)



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Richard Cooper
Re: what's the best codec to use to avoid "banding" during fade to black?
on Apr 29, 2009 at 11:33:05 pm

So Sorry Daniel!
Thats what I get for editing a segment, chatting on FaceBook, eating lunch and responding to these forums at the same time!

hehehe.

Anyway.... Daniel, Great idea!


Richard Cooper, FrostLine

Everyone has a story to tell..... what is yours?
http://www.FrostLineProductions.com


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Daniel Low
Re: what's the best codec to use to avoid "banding" during fade to black?
on Apr 29, 2009 at 11:45:09 pm

[Richard Cooper] "Thats what I get for editing a segment, chatting on FaceBook, eating lunch and responding to these forums at the same time!"

I know EXACTLY what you mean!



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