Magic Bullet deartifactor - how to

[Geoff Jak]

Ok maybe you're right thats there is nothing blocky in the images so Vegas Chroma Blur won't pick it up...BTW, should there be any sliders in the MB deartifactor for DV/ There isn't any here.

The DVD saga is this - loss of sharpness and contrast from what I see is going on in the edit. If i switch to the external monitor [a Tv] during editing, sharpness is great. Thats with no CC or Fx. By the time I use the default settings in DVDA 3 for PAL, two things have happened - sharpness takes a dissapointing hit and so to does contrast - a noticeable flatness has veiled itself over the entire program. So they are the things i am trying to clean up.

[Jarrod Whaley]

Originally Posted by Geoff Jak

BTW, should there be any sliders in the MB deartifactor for DV/ There isn't any here.

No, the settings aren't adjustable in the MB deartifactor--which is why I was saying you have more control with Vegas' chroma blur.

Originally Posted by Geoff Jak

The DVD saga is this - loss of sharpness and contrast from what I see is going on in the edit. If i switch to the external monitor [a Tv] during editing, sharpness is great. Thats with no CC or Fx. By the time I use the default settings in DVDA 3 for PAL, two things have happened - sharpness takes a dissapointing hit and so to does contrast - a noticeable flatness has veiled itself over the entire program. So they are the things i am trying to clean up.

OK, now we're cooking with gas. :)

Some of that is just due to the fact that the video has been highly compressed, so there's not too terribly much you can do. You might try rendering your project to an .avi intermediate before going to MPEG and then boosting sharpness and contrast ever so slightly before rendering using a DVDA template. It may take some trial and error, but if you can find a "sweet spot" where you're not adjusting those two things so much that you go to far with them, but also making sure there's enough of an adjustment to make a difference, then you might be able to improve your image a bit. But again, DVD video is extremely compressed, and that means you're throwing out huge chunks of the original image data. That's just the nature of the beast.

Someone else might have better suggestions.

[Lee Wilson]

On the chroma blurring side of things...

I find that using a median filter (set to around 2) on the chroma of a blocky DV section of footage gives a better result than using a chroma blur.

I am not sure how you would do this in Vegas, but I achieve it in After Effects by simply applying the median plug-in to a blank layer, make that layer an adjustment layer and then set its transfer mode to 'color'.

Works much better then MB deartifactor (really!) and like Jarrod pointed out with regard to 'chroma blur' you have much more control over the effect.

[Seth Bloombaum]

Originally Posted by Geoff Jak

...By the time I use the default settings in DVDA 3 for PAL...

Don't do it!

Do your MPEG2 renders in Vegas - you'll get much more control of the results. The defaults in either program aren't that great.

Check out Edward Troxel's excellent newsletter at www.jetdv.com for some basic guidance on this, Vol. 1 #7 has the info. Also look at Vol. 4 #1. Note that Edward's bitrate table is for NTSC video at 29.97fps, with PAL at 25 you have a few more bits to give to quality.

Try it - I think you'll like the results.

[Glenn Chan]

The best the Magic Bullet deartifactor can hope to do is to smooth some of the chroma blockiness in 4:2:0 or 4:1:1 color space. Red Giant says that their deartifactor uses a "proprietary engine" to accomplish this smoothing. But if you think about it, blurring is about all that can be done. You can't add pixels that weren't there when the camera threw them out to compress the original footage. :) I guarantee that if you try both the MB deartifactor and the Vegas chroma blur, you'll get pretty much the same thing. Either one of these techniques will help with compositing and chroma key and things like that, but only a tiny little bit. There's no real "magic" plugin that can fix everything in post. :)

There are tricks you can use to improve the chroma. One of them is chromaticity-style interpolation (you intepolate in a chromaticity-style color space instead of a chroma-based color space). You can see the difference between these three images (they have 300% zoom to make things easier to see):

http://glennchan.info/articles/techn...e-original.png original
http://glennchan.info/articles/techn...romaticity.png chromaticity-based interpolation
http://glennchan.info/articles/techn...a/e-chroma.png chroma based interpolation

It just so happens that all chroma-based interpolation has a tough time with red lines on a black background. No 4:2:2 codec that I'm aware of can do it without visible artifacting.

In more real world situations, those small chroma errors may not be a big deal. Red lines on a black background are exceedingly rare, and your footage will likely go back to 4:2:2 or 4:2:0 anyways (and they will get screwed up again).