Banding Problems

[Mark Andersen]

Help. I am suddenly getting lots of banding on output form Redcine. I've tried JPG (which used to work great for moderate compression deliver) Apple pro res HQ, and a bunch of others. Before build 16 and the newest Redcine. everything was fine but now banding is a real issue. I am using RC to grade and output footage for compressed digital deliver (AKA stock) almost all stock footage that is digital is either PhotoJPG quicktime or Apple Pro Res 422. but these are coming out of RC as crap. any ideas?

 

[John Tissavary]

Try outputting DPX - are those banded, too?

If not:

Can you identify any settings in RC that are different than previous? Perhaps you could post screenshot of your settings in problem renders.

I'm rendering tons of build 16 out of Scratch w. no banding whatsoever, and RC uses same code for r3d transcoding.


cheers,

jt

 

[Mark Andersen]

thanks john. I am not familiar with DPX, not sure what to do with all those frames (or how to see them). I will try to do screen capture. I am wondering if the problem lies in the REDspace color and gamma, should i go back to camera RGB or or some other colro space and gamma?

 

[Michael Schrengohst]

Try exporting 16 bit tiff files using REDLOG. Then bring those frames into After Effects 16 bit project for grading. Output your PhotoJpeg or ProRes from there.

 

[Paul Leeming]

Don't know if it's related but I've been seeing this when simply viewing the footage too in the new builds. Maybe the new ability to scrub quickly even on a Full Res setting was done by lowering display bit precision or some such? Could just be a bug. Hope it gets solved....

Paul

 

[John Tissavary]

DPX file can be viewed in After Effects, and there are also a few free applications that will allow you to use it, including http://www.graphicsmagick.org/
and
http://djv.sourceforge.net/

You don't necessarily need to view the entire sequence, just check out sample frames for banding problems.

One thing to keep in mind is that visible banding can happen anytime you display smooth gradients on an 8bit monitor, though it is strange that if that were the case the banding is only noticed now. But I see banding on any of my 8-bit computer monitors if the image content is right for it.

The reason I've singled out DPX is because it will always be the most reliable image transcode in RedCine, as it is the most widely used format in DI. RedCine shares a render engine with Scratch, a DI tool, and Assimilate has had a lot of focus on that format (I'm assuming) since it is in great demand by customers.

cheers,

jt

 

[Mark Andersen]

thanks for your input guys. One this that is wrong here is that a 8 second clip is coming out of RC as a 20MB file (way too small) so it's getting really compressed or losing color depth, I used to get 150-200 MB files with a similar clip and the same settings: QT/Jpeg/1080x1920/maximum/linear.

 

[Morgan Schmidt]

Greetings,

I second this problem, I ran into problems with a VFX house from footage rendered out of RedCine in the same manner (QT/Uncompressed 10-Bit 4:2:2/Maximum). They said it looked like the files were made in 'Thousands of Colors', where this sort of uncompressed would have billions of colors...

Morgan Schmidt
DP/LA