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H.264 color issues


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Has anybody been using the QT H.264 compression? I have begun to, and while I like the overall quality and file sizes, there seems to be a problem with the color & contrast getting washed out. From other searches I've done it seems to be a common problem but I haven't seen a solution for it yet.

 

Just wondering if anybody else is using it and what their thoughts are.

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Been using the filters inside the video export set-ups. Usally all it seems to take is poping the saturation just a little bit...sometimes more. Less agressive compression helps sometimes too.

 

I view it, right or wrong, as the luminance of the image being maintained at the sacrifice of color information. You lose some detial in the pixels for compression and in it's place the average luminance in rgb. I've had it go both dark and light. Generally with less contrast. Though using a contrast filter seems to burn it or wash it....and upping the saturation helps it. Been using H.264 since about 3 months after QT started using it, at least weekly.

 

Are you/can you do anything in comp, like levels or curves. Tighten up the histogram, by channel or giving the curves a pop seems to help too. Seems lately the only time I've had any problems is taking raw sequences right out of render, not doing any compositing. Levels adjustment is just the normal last step before rendering in comp, by me.

 

WDA

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Thanks for the response, William.

 

I am looking into the filters too. I guess it is just a matter of trial and error to find the right effect. Unfortunately it sounds like you are saying each animation comes out different so there will never be those 'perfect' settings.

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What I just discovered in Quicktime is that you cannot use any 2 filters in combination with each other. For example, I would like to use the brightness/contrast filter together with the saturation filter, but you can only do one at a time. Unbelievable! This has been one of the most frustrating experiences ever!

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Hmm, thanks again. So I guess it still boils down to a guessing game. So today, I ended up exporting the uncompressed, color bashed version out of Combustion, and then not doing any filters in QT when I exported to h264. It still was off, but not too terrible. No matter how dark you make your frames, the h264 doesn't seem to allow for a pure black. Even the blacks are light colored, and there's nothing you can do about that.

 

One interesting thing I read on another forum, is that you view a h264 movie in itunes, it will display the colors correctly and not wash them out. I tried it and it's true. Furthermore, if you go into the quicktime player advanced settings, and set the video mode to Safe Mode, it will also affect the color and display it darker. Unfortunately that option is off by default in QT, so there is no way to get the mass popuation to change their player preferences so they can see the color accurate animation. Crazy I tell ya.

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H.264 codec works in YUV colour space. Apparently Quicktime does a poor job of the RGB to YUV conversion when creating H.264 and this is the root of the problem.

 

The problem and the solution. Try a file format out of combustion that is Native YUV that QTpro understands.... conversion in QT RGB>YUV is not required, should yield better results after compression. Combustion does a better job of rgb>YUV to begin with, I believe, even so you should be able to tweak the YUV output for 'correctness' before rendering.

 

What I thoght was going, but couldn't recall for sure. Ran across this in another forum. I don't play in the YUV color space as an output, much at all so won't offer any guesses as to file formats.

 

If you get something on those lines to work...post it up I'd like to know ;)

WDA

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