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band problem
Let’s say I want to blur a text, or put a 200 pixels feather to a mask… On my computer screen everything is perfect but on my monitor (simple tv), I see some banding (some kind of bad gradient). Even with a 32 bits project. So here’s my question… Why do I have this problem? After rendering will I still see the banding?
My computer
Intel dual core Imac 20 inchs;
video card: x1600 ATI
Preview: firewire and old digital camera (canon zr10).
Sofware: After Effect 7 (I know the problem between adobe products and intel dual core)Thanks for the help.
May the force be with you
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8 Replies
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You can set up your project to 32 bpc/float all you want, but if you’re using a Firewire DV device for monitoring, then you’re gettting a 8 bpc preview with heavy compression on your video screen. Two routes: getting an uncompressed board for monitoring (very cheap these days), or if you’re really want to go Firewire DV, you’ll need to experiment with tiny amounts of monochrome noise to “break” the gradients and get rid of banding. Not as good as the first option, of course 🙂
PS: I see you have an iMac, then you would only have two options for uncompressed monitoring: one of the AJA IO LA or LD models (from $900, SD only) or the Matrox MXO ($1000, HD/SD but output only). Unfortunately, all other Decklink and AJA devices are internal cards which won’t work with the iMac.
Adolfo Rozenfeld
Buenos Aires – Argentina
https://www.adolforozenfeld.com
adolfo(AT)adolforozenfeld.com -
Thanks for the information (that was a fast answer). For the trick with the noise… I actualy found that by myself. But like you said… not always good. 🙂
Thanks again.
May the force be with you
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On your monitor you are rendering to DV (8 bit, 5:1 compression, 4.1.1 color. You’re going to get bad banding on gradients. If you render to a 10 bit QT and don’t see the banding in the QT you should be fine. But there’s no way to view 10 bit through DV to a TV.
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That said, I preview uncompressed component via a Decklink Pro to a Sony broadcast monitor and I still get nasty banding on subtle gradients out of AE or PS. I’ve tried 8bit/16bit in PS and AE to no joy. It is a bit of an annoying problem. My old Quantel Paintbox Express had no such banding and as far as I’m aware that was just bog standard 8bit with component monitoring.
Does this mean it’s an issue with Adobe software then? I’d love for someone to once and for all explain why this happens!…
*Production Studio Premium / *Combustion 3
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Win XP Pro SP2 / Intel P4 3GHz / 2GB RAM / GeForce FX5200 / DeckLink Pro / Sony BVM-20G1E / DVS SDI Clipstation / 110GB boot/80GB media/600GB RAID-0 -
Nope. Not an Adobe issue. From what I understand, the Decklink truly is a 10 bit card (depending on model, even more than that) but only though SDI. The analog converters (for component I/O) apparently are 8 bit. That may not be true anymore for newer models. It was discussed heavily a couple of years ago. Still, I am not seeing much banding on the Decklink Extreme output.
As for the Quantel box being 8 bit, it also depends on the gradient technique. Some gradient generators have more aggresive dithering applied, ofr example.
Adolfo Rozenfeld
Buenos Aires – Argentina
https://www.adolforozenfeld.com
adolfo(AT)adolforozenfeld.com -
i used to get banding problems on a paintbox, however the airbrush would dither colors, so you could use this to help out…
i’ve found any time you try to create a gradient/blend between to similar colors on any ntsc system you’ll start to notice banding. even if you work in 16 bpc rgb, if you output to ntsc 10 bit you’ll see banding (ntsc 10 bit most closely resembles 8 bpc rgb).
if you work in 16 bpc and can output to 12 bit color, or 4:4:4, you probably won’t see any banding (although i think if you colors are close enough and the area is large enough, you may start seeing banding anyway).
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This is all very true, but for the sake of helping the original poster, it’s worth noting that the banding you get out of an uncompressed device like the ones we’re mentioning is nowhere near what he’s getting with Firewire DV output.
Adolfo Rozenfeld
Buenos Aires – Argentina
https://www.adolforozenfeld.com
adolfo(AT)adolforozenfeld.com -
Thanks Adolfo/Moldybot,
Didn’t realise the component o/p on the Decklink was 8bit..that might explain it. That said, all our NLEs are currently 8bit anyway (old Quantel Editbox and v7 Media Composer – tell me about it..we need to upgrade!) so unless I output directly to the final tape from my machine all my GFX get downsampled anyway. Good to know about the component thing though, thanks.
I guess the noise filter will continue to be the fix then…
*Production Studio Premium / *Combustion 3
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Win XP Pro SP2 / Intel P4 3GHz / 2GB RAM / GeForce FX5200 / DeckLink Pro / Sony BVM-20G1E / DVS SDI Clipstation / 110GB boot/80GB media/600GB RAID-0
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