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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Compression Artifacts

D

Daniell Simmons

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Hi all,

I just got back from a helicopter shoot with a Red in Africa. I've been looking at the footage for a week now, and although it looks great, I've been noticing some pretty severe compression artifacts

5825_1196738630.jpg
 
Cardmaverick said:
I would second an export, at first, when I played with Jim's dragster clips, I wasn't too hot on how they looked, but it was just a viewing setting.
Click to expand...

Yes, have exported tiff, .exr and dpx and get the same results each time. Admittedly, it's been done with the same video card (NVIDIA Quaddro FX 4400). Would a different card give better results?

B
 
No this is an issue that is being addressed. Try the latest firmware (Build 11) it improves the problem a bit, but it still needs more optimization.
 
It's amazing to know that this stuff will keep getting better.

It's blowing my mind right now..
 
REDCode might improve with time, but I'm sorry to say the footage you've shot right now is what it is. That looks like too low of bitrate wavelet compression and once that data has been discarded it's gone.
 
also remember we are shooting moving images, these issues and artifacts are not present at 24 fps on a 30' screen.

have you ever put a feature film that has played more than a day at a multiplex through a simple magnifying glass...you want to see artifacts, dusts, cuts, scratches...

i know it is a not the best answer, but when you look at the options for watching this stuff, it will never be seen like you are dissecting it.

i have done digital projection screening with 2k and 4k projectors for 4 years for all the major studios, distributors and festivals and this footage we are shooting now is unlike anything that has come before it.

again, yeah it might look a bit compressed when blown up in a still image, but that is not how it will be seen by the audience & it is compressed.
 
kosmos3d said:
also remember we are shooting moving images, these issues and artifacts are not present at 24 fps on a 30' screen.

have you ever put a feature film that has played more than a day at a multiplex through a simple magnifying glass...you want to see artifacts, dusts, cuts, scratches...

i know it is a not the best answer, but when you look at the options for watching this stuff, it will never be seen like you are dissecting it.

i have done digital projection screening with 2k and 4k projectors for 4 years for all the major studios, distributors and festivals and this footage we are shooting now is unlike anything that has come before it.

again, yeah it might look a bit compressed when blown up in a still image, but that is not how it will be seen by the audience & it is compressed.
Click to expand...

well said.
 
kosmos3d said:
also remember we are shooting moving images, these issues and artifacts are not present at 24 fps on a 30' screen.

have you ever put a feature film that has played more than a day at a multiplex through a simple magnifying glass...you want to see artifacts, dusts, cuts, scratches...

i know it is a not the best answer, but when you look at the options for watching this stuff, it will never be seen like you are dissecting it.

i have done digital projection screening with 2k and 4k projectors for 4 years for all the major studios, distributors and festivals and this footage we are shooting now is unlike anything that has come before it.

again, yeah it might look a bit compressed when blown up in a still image, but that is not how it will be seen by the audience & it is compressed.
Click to expand...

That may be true, but these days, not everyone is going to shoot and go straight to projection with no digital adjustment of the image.
 
Great tip about blurring the blue channel.
But most of us (camera people especially) will not be too crazy bout adding yet another step just to process footage.
Again, I'm sure these noise issues will improve once RED has time to address them.
 
bgunsberger said:
I'm investigating using the camera to shoot plates for backgrounds for a vfx-heavy feature and the ability to stabilise, grade, zoom, sharpen etc is critical.
Click to expand...

Well his comments still are true. If you are rendering out a plate to be used in an image comp with smoke and cc and other VFX, that makes his point even more valid. Once you are moving your image in the final comp, this pixels are going to be re-rendered anyway.

My question to you is why you are wanting to make comps to zoom in on with footage rather than, say, a digital camera like a 10 MP Canon Rebel. You get more resolution which is better for comp work anyway, plus you don't have to constantly worry about motion blur in your plate frames. That would be my number one concern.

And if you were using footage as the plate, then, again he is right- the artifacts won't be visible because of the motion.

I understand your concern but I think it's rather mute at this point.

(Unless you don't have a digital camera)
 
ChrisLyon said:
Well his comments still are true. If you are rendering out a plate to be used in an image comp with smoke and cc and other VFX, that makes his point even more valid. Once you are moving your image in the final comp, this pixels are going to be re-rendered anyway.

My question to you is why you are wanting to make comps to zoom in on with footage rather than, say, a digital camera like a 10 MP Canon Rebel. You get more resolution which is better for comp work anyway, plus you don't have to constantly worry about motion blur in your plate frames. That would be my number one concern.

And if you were using footage as the plate, then, again he is right- the artifacts won't be visible because of the motion.

I understand your concern but I think it's rather mute at this point.

(Unless you don't have a digital camera)
Click to expand...

I doublt Animal Logic is going to have a problem getting a 10mp still cam, being one of the premiere vfx houses in the world.

I agree, basically, that the blue channel noise is not going to be much of an issue with plates. But it is a concern, and definitely an issue that needs to be solved asap. As they say, shit in, shit out... especially when you start applying moves in post.

What I'm confused about is that some are reporting the blue channel noise as very noticeable, and others aren't . Is this a difference in critical observation or variance between cameras/firmware/lighting/subject matter etc...?

I believe it's a combination of subject matter and exposure more than just exposure. I definitely noticed noise in some of our night shots, but less so in others with nearly the same exposure.

Anyway, I know Red is aware of this and an improvement is at hand, so I can't wait to see it!

cheers,

john t.
 
The shot that 'bgunsberger' presents is basically almost as demanding as it gets for a digital motion camera (with spatial lossy data reduction.. ) The minutia detail and the color balance are tricky. I mention this for perspective not because I don't want it addressed..

I personally (when there is storage that supports this.. redram?) would like to see higher data rate options.

Michael
 
I think Michael Lindsay's point is right on- the Red compression excels on a lot of "typical" feature shots where some significant part of the frame is not in sharp focus. But if you've got a long shot full of foliage detail where the entire image is in focus, something has to give, and apparently it's the darker areas.
 
ChrisLyon said:
Well his comments still are true. If you are rendering out a plate to be used in an image comp with smoke and cc and other VFX, that makes his point even more valid. Once you are moving your image in the final comp, this pixels are going to be re-rendered anyway.
Click to expand...

Quite the opposite. As the image may be graded, stabilised, retimed, etc, starting with good material is even more important, as each of these image-processing operations can degrade image fidelity.

ChrisLyon said:
My question to you is why you are wanting to make comps to zoom in on with footage rather than, say, a digital camera like a 10 MP Canon Rebel. You get more resolution which is better for comp work anyway, plus you don't have to constantly worry about motion blur in your plate frames. That would be my number one concern.
Click to expand...

The shots we're working on involve mid-air action above and through forests, requiring moving vegetation and lots of parallax motion. Static panoramic capture is not an option.

ChrisLyon said:
And if you were using footage as the plate, then, again he is right- the artifacts won't be visible because of the motion.
Click to expand...

The artifacts are quite visible at 2k on a DP90 pretty much out of the box
 
Ben to put it simply. REDCode is over compressed for any real serious manipulation of the blue channel. I would investigate the RAW port option to shoot uncompressed. Hopefully there'll be a hardware 4k Cineform option early next year which could enable aerial footage without compression. Or else you can join in the chorus (currently of one :) ) asking for 50MBs REDCode RAW.
 
Also I'm seeing some compression glitches in that footage I haven't seen before. It looks like a de-mosaic issue.
CompressionGlitches.jpg


Are those in the original or a result of online posting?
 
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