Blockiness in reds?

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brianlees
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Posts: 63
Joined: Wed Mar 28, 2007 2:17 am

Blockiness in reds?

Post by brianlees »

I did an AppleTV preset rip of Serenity on my Mac. There is a scene (which most browncoats deny exists...including me! :D ) where it is very dark and bathed in red light. The screenshot below shows how there is some "macro blocking" (wrong term, I'm sure). It is much more evident while in motion, but look around the faces and the belt buckle. This screenshot is in the native resolution from the preset and is not adding the artifacts.

Image

Now, I read another post from just over a year ago where jbrjake notes that this happens with most any codec. The post on another forum was very technical (color spaces, etc). However, I think it may have answered my question....so this might be fruitless, but....

Does anyone have any suggestions on how I might reduce this problem as much as possible and still stay within the specs of the aTV?

Also, I know it is not possible, but if you could increase the bitrate for just this section of the movie, would it work in theory? (That is just a hypothetical question peaking my interest that is outside of aTV compatibility and the current functionality of Handbrake.)

EDIT - I just realized I posted this in the Mac forum and not the Devices forum. Since it is directly about the aTV, I should have posted it there, I guess. Sorry about that. Feel free to move it.
rhester
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Joined: Tue Apr 18, 2006 10:24 pm

Re: Blockiness in reds?

Post by rhester »

This is the reason for the creation of VAQ (Variable Adaptive Quantization), which is in SVN and will appear in the next public release.

Rodney
brianlees
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Posts: 63
Joined: Wed Mar 28, 2007 2:17 am

Re: Blockiness in reds?

Post by brianlees »

Will VAQ work with an aTV (my guess is probably not)? Also, any good links about it? It is barely mentioned in the wiki and I would like to learn some more about it.
rhester
Veteran User
Posts: 2888
Joined: Tue Apr 18, 2006 10:24 pm

Re: Blockiness in reds?

Post by rhester »

VAQ will work with anything - it's just a means of redistributing bits.

Search for "VAQ" or "Variable Adaptive Quantization" on the doom9 forums (http://forum.doom9.org/) for more information.

Rodney
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