A

Anonymous

Question

Confusion about ProRes bit depth export settings

Forum|Forum|9 years ago
June 14, 2016
3 replies
16749 views

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!

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S

S29454301mf9x

Participating Frequently

ProRes 422 is 8-bit

ProRes 422HQ is 10-bit

Averdahl

Community Expert

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

Inspiring

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.

laneo

Participant

+1 here. Where do those numbers come from?

trashcaneron

Inspiring

I am confused about the same thing!

R Neil Haugen

Legend

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.

Everyone's mileage always varies ...

M

Meg The Dog

Inspiring

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

S

Shane_P

Inspiring

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.

A

Anonymous

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!

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