Confusion about ProRes bit depth export settings

[Guest]

ProRes 422 is 10-bit, correct? Which would equate to 30-bit color (10 bits per channel), correct? Why is there only an option for 24 and 48-bit? Is that implying Premiere renders in 8-bit depth is you pick 24-bit, despite creating a 10-bit file? And what is the point of 48-bit for ProRes 422? That would imply 16 bits per channel which 422 isn't capable of, unless I've totally lost the plot!

[Meg The Dog]

Not sure if this answers your question, but -

From:

https://www.apple.com/final-cut-pro/docs/Apple_ProRes_White_Paper.pdf

Sample Bit Depth

The number of bits used to represent each Y’, CB, or CR (or R, G, or B) image sample determines the number of possible colors that can be represented at each pixel location. Sample bit depth also determines the smoothness of subtle color shading that can be represented across an image gradient, such as a sunset sky, without visible quantization or “banding” artifacts.

Traditionally, digital images have been limited to 8-bit samples. In recent years the number of professional devices and acquisition techniques supporting 10-bit and even 12-bit image samples has increased. 10-bit imagery is now often found in 4:2:2 video sources with professional digital (SDI, HD-SDI or even HDMI) outputs. 4:2:2 video sources rarely exceed 10 bits, but a growing number of 4:4:4 image sources claim 12-bit resolution, though with sensor-derived images the least signi cant one or two bits may have more noise than signal. 4:4:4 sources include high-end lm scanners and lm-like digital cameras and can include high-end computer graphics.

Apple ProRes 4444 XQ and Apple ProRes 4444 support image sources up to 12 bits and preserve alpha sample depths up to 16 bits. All Apple ProRes 422 codecs support up to 10-bit image sources, though the best 10-bit quality is obtained with the higher-bit-rate family members—Apple ProRes 422 and Apple ProRes 422 HQ.
(Note: LikeAppleProRes4444XQandAppleProRes4444,allAppleProRes422codecs can in fact accept image samples even greater than 10 bits, although such high bit depths are rarely found among 4:2:2 or 4:2:0 video sources.)

MtD

[Shane_P]

https://larryjordan.com/articles/pick-the-right-version-of-prores/

Here's some more info from Larry Jordan's website.

Hope this is helpful friend.

[Guest]

Ha, I appreciate the effort from both of you, but neither of those articles helped, sadly. It still doesn't explain why Premiere has 24/48 bit options for ProRes 422, a 10-bit codec. Shouldn't it be 30 instead of 24 (10-bit per channel, not 8)? And if not, why? And what's the 48 doing? 16-bit per channel or 12-bits per channel with alpha (despite 422 not supporting alpha)?

Thanks though!

[jeffp68340199]

Hi,

Would love to help if I can, however I'm on a PC which does not offer the ProRes export options for me to look at. If you can perhaps provide a few screen shots showing the available export settings that you are questioning, that would make it easier for myself and others to understand the issue and offer some insight.

Thank you

Jeff Pulera

[Guest]

Here's what I'm talking about. ProRes 422 is a 10-bit (per channel) codec. So why am I getting 24 and 48 as options? What do they do in addition to "Render at Maximum Bit Depth" which would make sure any 32-bit effects get rendered on 32-bit frames?

[SAFEHARBOR11]

Hmmm...that is confusing! Well, as most formats offer 24 and 32 options for Depth, with 32 being the option to include Alpha channel, I will assume then that 24 bit is no alpha, and 48 is with alpha then. The Apple White Paper above does mention that possibly 12 bits are used for alpha channel formats, so that explains the 48 (12+12+12 for image, + 12 for alpha channel). Does not explain the 24...but it's just a label really, maybe it's incorrect?

I would not concern myself really. Yes, it's a mystery, but in the end does it really matter what the label says? Tons of professional Adobe editors are using ProRes and I've never seen this questioned before, so must not be an issue. Does the export look good and suit your needs? That is the bottom line. But would love to see Adobe explain this just for the sake or curiosity.

Thanks

Jeff

[Guest]

Maybe I'm just being picky, but those numbers dont seem to add up since ProRes 422 doesnt offer an alpha channel (only PR 4444) so why would there be a 48-bit option? Hell, when you DO choose PR 4444 you can go up to 64-bit! Which I assume is 16bpc for 4 channels (RGBA), but this seems odd since it's only a 12-bit codec. THEN you might say "well, maybe it's so Adobe renders in a high bit-depth space, but isn't that the purpose of the Maximum Bit Depth button? So what's the difference? Someone has to know! lol

[adobe user 1l35433405]

Any updates on this question? I'm wondering the same thing.

[laneo]

+1 here. Where do those numbers come from?

[trashcaneron]

I am confused about the same thing! 

[R Neil Haugen]

Read that linked article up top. There's a ton about video imaging that is simply not obvious, nor do they make sense until you've learned a lot more details. Like ... color spaces, gamut, and volume, compared to the different dynamic ranges available ... yeesh.

[S29454301mf9x]

ProRes 422 is 8-bit

ProRes 422HQ is 10-bit

[Averdahl]

According to the Apple ProRes White Paper your statement is incorrect.

From the Apple ProRes White Paper:

"All Apple ProRes 422 codecs support up to 10-bit image sources, though the best 10-bit quality is obtained with the higher-bit-rate family members - Apple ProRes 422 and Apple ProRes 422 HQ"

Source: Apple ProRes White Paper

[trashcaneron]

White paper is correct ! After a deep dive over the last few days. 

Here's the bit-depth information as I understand it. 

A depth of 24-bits is equal to 8-bits per channel (R,G,B) 24/8=3

A depth of 48-bits is equal to 16-bits per channel (R,G,B). 48/3=16

Although your codec is only 10 or 12 bpc, I've found that over-sampling to 48 bits is better than up-sampling from 24 bits. Extremely marginal, but you can tell on a zoom-in. That said, if your content is made in an 8bpc space (or comes from an 8bpc source) and then over-samples to 48, it won't look any better.  

In After Effects, for example - you want to work in 16bpc and then render in 10bpc - there is a marginal difference between selecting millions or trillions of colors here. 

I did a series of tests comparing these things all using sRGB with a rec.709 monitor in After Effects. Sources were: Gradient content. Generated content. RAW video color corrected. There are more options to mess with in AE and it's easier to render a/b tests. 

16bpc (aka 48bits) working space --> Depth (trillions) rendered --> 10bpc final codec always looks pretty good

16bpc working space --> Depth (millions) rendered --> 10bpc final codec usually looks good - sometimes more noise

8bpc (aka 24bits) -->Depth (millions) rendered --> 10bpc can look at little dirty in your gradients for sure. 

Confusingly, you can work in 16bpc, set depth to trillions (equivalent of 16bpc), and set your codec or image sequence to 8bpc. I call this 16-->16-->8. This looks basically identical to 16-->16-->10 and 16-->8-->8 is not too far off either... ! For most things, the most critical piece of the puzzle is the working space IMHO.