Banding of light fall off within Scarlet?

[Abe Espinoza]

Hello Reduser Community,

I’m new to this RED game and thought I would introduce myself, and ask some questions along the way, as I’m sure most of you have probably gone through the learning curve I’m headed towards.

Anyhow, on to the question – I have been doing some shooting on a Scarlet in order to come to grips with this bad grrrl. I have to say my initial impressions are very good, but I have noticed that I am getting some banding when transcoding/ rendering out clips in RCX Pro 14/ Premiere Pro CS6 and am wondering if anybody else has seen this in their footage.

I’m primarily outputting ProRes 444 files @ 2K (2048 x 1152). I figured since the camera is processing the RAW data @ 16bit, and with all the information found in the 4K file, my 2K output files would look super clean, but alas, that is not the case, all of the time.

Compression was set to either 6:1 for 24fps, or 8:1 when shooting 30fps on a 23.98 timebase.
I know it’s not my glass, I’m using Leica R lenses… & a 2011 MBP 15” 2.4GHz i7 Quad-Core with 8Gigs of RAM, not that it should matter.

I have attached a couple of screen grabs from the ProRes 444 2K file outputs I have created from two separate days.

Clip #1 – Banding is evident in the hair of the out of focus model to the left. RCXP 14 - Pro Res 444 2K transcode.
Clip #2 – Banding is evident in the background under & beside the stairway. Premiere Pro CS6 - ProRes 444, 2K movie render.

I’m hoping someone will tell me it’s just noise and it can be remedied with a healthy dose of Neat Video. Hey, a man can dream, right? More than anything, I hope this isn’t a wake up call.

Thanks a bunch,

Abe Espinoza

 

[Abe Espinoza]

Just noticed these screen grabs don't pop up at their full image size... Could any of you nice folk help out with this as well?:willy_nilly:

Thanks...again.

Abe Espinoza

 

[Maik Müller]

Yep, directly attached images get downconverted. To post full-size images you have to upload them to a external host and post the links with the IMG-tag around them.

One question, do you see the banding in the original R3Ds too? If not, its just a transcoding-problem. That brings one great rule in mind: Stay in REDCODE as long as you can, avoid transcoding.

Hmm, but for a start, you could play with the different resizing algorithms and check the sharpening options in RCX (maybe lower those settings or disable them).

 

[Nick Pasquariello]

Yeah, my gut instinct is that it's something you're doing to the metadata in RedCine-X Pro before you output it. Or has something to do with your settings.

What ISO are you shooting at? Something that takes many shooters a long time to wrap their head around is that the only real way to change your ISO is to physically swap out your sensor (which, of course, isn't possible). Ideally, the rule is not to go outside of the 320-800 ISO range (different shooters have different preferences for what the sweet spot is within that range. Personally, I like 500 or 640.) When you adjust the ISO, all you're doing is adjusting how the camera is treating the data that it gets from the sensor, which is passing along the same readings regardless of the ISO.

If you crank your ISO too far in one direction, and then light for that ISO, you could be introducing a variety of issues to your actual footage, one of which could possibly be what you're seeing. It's hard for me to tell for sure without seeing a full res image.

 

[Abe Espinoza]

Maik - Thanks for the upload tip. One question - How do I go about placing an IMG tag around the links. I'm not a frequent poster to the web.

I took a good look at the R3D files and as you stated, there is no banding going on within those original files. I understand where you are coming from in regards to staying native with the files, but I have to render them out eventually, so I have to figure out what's going on/ what i'm doing wrong. Thanks for lead in the right direction.

Abe Espinoza

 

[Hrvoje Simic]

Maik - Thanks for the upload tip. One question - How do I go about placing an IMG tag around the links. I'm not a frequent poster to the web.

You can use Tinypic or similar image hosting websites and upload the picture there.
Once you do that, all is self-explanatory.

 

[Maik Müller]

You can use Tinypic or similar image hosting websites and upload the picture there.
Once you do that, all is self-explanatory.

Yep this, or if you put images on your own web-site, then post the links in here in this form:

Good to know there is now banding in the R3Ds.

 

[Abe Espinoza]

Nick,

I'm essentially just fiddling with the Luma Curve to add contrast in RCX Pro, and outputting a QuickTime ProRes 444 2K file (2048 x 1152) with no other adjustments.I do understand how the ISO settings work within this camera, but can understand why you brought it up. I shot these clips with an ISO setting of 320 (which is pretty much what I've been shooting in regards to ISO), Red Color 3/ Red Gamma 3, but switched over to REDLogFilm to get the most out of the file. I posted grabs from both RCX Pro & the Rendered QT files from Premiere CS6 grabs if that would help. The RCX Pro RAW files are clean of any banding, so it has to be my renders that are not holding up. I can also provide you with R3D's if interested.

Here are the links:

Thanks,

Abe Espinoza

 

[Rob Ruffo]

It is pretty much impossible to introduce banding in Red footage. Something is wrong in your transcode/post process if you are seeing it.

Try grading the Red files directly, not transcoding first, then grading.

Quicktime 444 is not bullet-proof at all, but Redcode is. You can easily get banding by over-pushing a Quicktime file. If you must edit Quicktime (not sure why you would) then grade as close as possible to what you need in RCX (no Redlog film, use a "final output gamma" that looks like what you want as a final result).

We have pushed Red footage in all kinds of directions and have never seen banding, not once. Noise, sure, but never banding. But we never transcode first - only at the end.

 

[D Fuller]

Nick,

I'm essentially just fiddling with the Luma Curve to add contrast in RCX Pro, and outputting a QuickTime ProRes 444 2K file (2048 x 1152) with no other adjustments.I do understand how the ISO settings work within this camera, but can understand why you brought it up. I shot these clips with an ISO setting of 320 (which is pretty much what I've been shooting in regards to ISO), Red Color 3/ Red Gamma 3, but switched over to REDLogFilm to get the most out of the file. I posted grabs from both RCX Pro & the Rendered QT files from Premiere CS6 grabs if that would help. The RCX Pro RAW files are clean of any banding, so it has to be my renders that are not holding up. I can also provide you with R3D's if interested.

Here are the links:

Thanks,

Abe Espinoza

You're showing us screen grabs. Are you sure it's not just your monitor banding?

 

[Abe Espinoza]

Hi Rob,

What i did to this footage is:

1) Created an S - Curve for Luma within RCX Pro in Redlog film, so no real grading going on here, just a simple contrast adjustment.
2) I then output the files to QT Pro Res 444 @ 2k within RCX Pro.
3) Edited the QT files within Premiere Pro CS6 on a 1920 x 1080 sequence. The files were set to scale to frame size, with no other image adjustments.
4) I then rendered the project out to Pro Res 444 @ 1920 x 1080. Square Pixels, 23.98 fps. Set gamma adjustment to automatic.

I'm not sure I understand you when you say I should use a "final output gamma". I'm assuming you mean something the likes of rec.709, or another type of LUT? I tried editing the R3D files within Premiere Pro but my computer started getting clunky, so I created the ProRes files to see how my machine faired with these instead. I then decided to render my project from these files, and hence noted my problem.

I figured I should not have any issues like you stated Rob. Just trying to figure out what it is that I am doing wrong.

Best,

Abe Espinoza

 

[Abe Espinoza]

Hi David,

You might be right, because I am not sure. But, you can see the difference between the two comparison files labeled Clip #2 - both from the RCX Pro grab and that of the QT file grab. There is obvious banding below the staircase within the QT file grab, and none from the RCX Pro grab.

Best,

Abe Espinoza.

 

[Maik Müller]

Because we're looking at screenshots, one more idea... This could be just a playback problem. Try different players, under windows i prefer MPC-HC with LAV-Filters and MadVR-renderer. Another question, how does a 8bit-encode based on those prores-files look?
Regarding the resizing-algorithms that i did mention earlier, have you checked your RCX-export profile for that? You find that option under "Options/Software Scaling".

BTW, the image-tag works better if you give it a link directly to the image. Like this:

 

[Matt Ryan]

I guarantee you it's the compression. That's why you don't see it in the RAW but see it in the quicktime... Your squeezing 16bits for Epic/Scarlet and 12bits Red One down to 10 or 8 bits depending on your compression so your bound to see banding if you have gradations in your shot.

 

[Abe Espinoza]

Maik,

I just checked the software scaling option within my export profile in RCX Pro and it is set to Mitchell (smoother). Is there a better option? If so, please advise.
Thanks,

Abe Espinoza.

 

[Abe Espinoza]

Hi Matt,

I'm going to render out a Tiff sequence to see what results I come up with. Would you be so kind as to describe your transcoding procedures, as I would love to not have this problem. I believe you when you tell me it's the compression.

Thank you,

Abe Espinoza

 

[Marie Turock]

Just to be clear, ProRes4444 supports 12bit content. So, if your are transcoding R3Ds to ProRes4444, then it should not yield banding, visible quantization, or any other perceptual flaw. It has to be something that is applied to the process before sending it to transcode, OR perhaps the export settings aren't actually sending it to ProRes4444.

 

[Abe Espinoza]

You sir, were right on the money!

Tiff sequence looks exactly like the R3D's!

Thanks for that!

Abe Espinoza