Prores 4444 Problems

Question

Level 1

10 points

Prores 4444 Problems

Hi there,

I'm digitizing video from a 4:4:4 HDSR through an AJA Kona 3 card (ver 6.0.3) to Final Cut trying to create ProRes 4444 files. However when I look at these files on the scopes my black level does not sit at 0 but rather it seems to add a setup to 7.5. My white levels also seem to have dropped. This shows up on the FCP scopes and on outboard calibrated scopes (back out through the Kona card).

I've tried the same material with various other compressions (10 bit, Prores 422, etc) and all of those show the blacks at 0. As soon as I use ProRes 4444 the levels are raised. I've tried using Millions of Colors and Millions of Colors+ (although I don't need the Alpha channel) and I've turned the Gamma Correction off.

Is there anything else I could be missing? Is this just what ProRes 444 does? I can't find much documentation on this subject. Thanks so much for any help.

Ryan

Mac Pro Quad-Core Intel, Mac OS X (10.5.8), 2x2.66 Ghz 6GB RAM 1066 Mhz DDR3 FCP 7.0.1

Posted on Feb 17, 2010 10:35 AM

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Answer 1

Feb 17, 2010 10:43 AM in response to r_pears

Can you explain why you're using the 4444 version? What do you hope to accomplish?

bogiesan

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Answer 2

r_pears Author

Level 1

10 points

Feb 17, 2010 10:48 AM in response to David Bogie Chq-1

It's the client's request. I'm not sure why they need it, I'm just a monkey who pushes buttons.

I'm assuming that they're trying to retain the highest quality video with smaller file sizes so they don't have to go back to the tapes for an online. But that's just a guess. It doesn't seem to be an effects heavy film so I can't seem them needing to composite a lot.

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Answer 3

Feb 17, 2010 11:07 AM in response to r_pears

Ah. Yar, we're all edit monkeys around here.
Your client is probably mistaken about the utility of 4444. It is only useful when carrying an alpha from, say, Motion. In that case, going into Motion with 4444 is not necessary; they'd use 4444 on the output only.
I'm sorry I cannot help you with the level discrepancies and you are correct in not being able to find much documentation about the ProRes family. Searching the forum returned dozens of interesting threads, Shane Ross is the goto dude.

Ask your client if they really know what they're doing. Tactfully, of course.

bogiesan

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Answer 4

r_pears Author

Level 1

10 points

Feb 17, 2010 11:25 AM in response to David Bogie Chq-1

Thanks for the help. I searched the forum and couldn't find anything similar. I think going back to the client might be the best bet, you're probably right that they may not know what they need.

If I do find any more info on this I'll certainly post it.

Thanks!

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Answer 5

Feb 17, 2010 11:29 AM in response to r_pears

Thanks for the help.< </div>

You're welcome.
Give us a few more hours (or a day or two if you've got the time). Someone with a better understanding of the ProRes family may stumble upon the thread.

bogiesan

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Answer 6

ScottieB

Level 3

505 points

Feb 17, 2010 1:41 PM in response to David Bogie Chq-1

David Bogie Chq-1 wrote:
Ah. Yar, we're all edit monkeys around here.
Your client is probably mistaken about the utility of 4444. It is only useful when carrying an alpha from, say, Motion. In that case, going into Motion with 4444 is not necessary; they'd use 4444 on the output only.

bogiesan

Is this accurate? The ONLY advantage to ProRes 4444 is the alpha? Or do you mean in this particular instance (not much compositing/grading)? Wouldn't the extra color data (as opposed to the 4:2:2 versions of ProRes) offer you more flexibility in things like vfx or color grading? Or have I been tricked by marketing terms?

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Answer 7

r_pears Author

Level 1

10 points

Feb 17, 2010 1:52 PM in response to ScottieB

I'm not sure now. I've been doing some more reading and it sounds like it's the best way to maintain full quality from 4:4:4 HDSR without having huge file sizes.

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Answer 8

Feb 17, 2010 1:58 PM in response to ScottieB

ScottieB wrote:

David Bogie Chq-1 wrote:
It is only useful when carrying an alpha from, say, Motion. In that case, going into Motion with 4444 is not necessary; they'd use 4444 on the output only.
bogiesan

Is this accurate? The ONLY advantage to ProRes 4444 is the alpha? Or do you mean in this particular instance (not much compositing/grading)? Wouldn't the extra color data (as opposed to the 4:2:2 versions of ProRes) offer you more flexibility in things like vfx or color grading? Or have I been tricked by marketing terms?

Ah, sorry. I should have said "my only reason for using 4444..." but yes, you, and the rest of us are all (victims or) customers of Apple's superb marketing.

bogiesan

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Answer 9

Tom Wolsky

Level 10

152,815 points

Feb 17, 2010 2:33 PM in response to ScottieB

From the ProRes white paper:

• Apple ProRes 4444: The new Apple ProRes 4444 codec preserves motion image sequences originating in either 4:4:4 RGB or 4:4:4 Y’CBCR color spaces. At its remarkably low data rate as compared to uncompressed 4:4:4 HD, Apple ProRes 4444 supports 12-bit pixel depth with an optional, mathematically lossless alpha channel for true 4:4:4:4 support. Apple ProRes 4444 preserves visual quality at the same high level as does Apple ProRes 422 (HQ), but for 4:4:4 image sources, which can carry the highest possible color detail.
Apple ProRes 4444 is ideal for next-generation video and the most pristine computer graphics sources for cinema-quality compositing. For projects that previously required the Animation codec, Apple ProRes 4444 is a modern replacement with real-time playback support in Final Cut Pro. Because color detail is preserved, Apple ProRes 4444 is ideal for color grading with 4:4:4 image sources.
• Apple ProRes 422 (HQ): Boasting widespread adoption across the video post- production industry, Apple ProRes 422 (HQ) offers visually lossless preservation of the highest-quality professional HD video that a (single-link) HD-SDI signal can carry. This codec supports full-width, 4:2:2 video sources at 10-bit pixel depths, while retaining its visually lossless characteristic through many generations of decoding and re-encoding.
Apple ProRes 422 (HQ) can be used both as an intermediate codec to accelerate workflows for complex, compressed video sources and as an affordable, high- performance alternative to uncompressed 4:2:2 video.
• Apple ProRes 422: Apple ProRes 422 offers nearly all the benefits of its big brother, Apple ProRes 422 (HQ), but at a significantly lower data rate. It provides visually lossless coding performance for the same full-width, 10-bit, 4:2:2 sequences as Apple ProRes 422 (HQ) with even better multistream RT editing performance.
• Apple ProRes 422 (LT): Like Apple ProRes 422 (HQ) and Apple ProRes 422, the new Apple ProRes 422 (LT) codec supports full-width 10-bit video sequences, but at a target data rate even lower than these siblings. Apple ProRes 422 (LT) weighs in at 100 Mbps or less, depending on the particular video format. It balances incredible image quality with small file sizes, and is perfect for digital broadcast environments where storage capacity and bandwidth are often at a premium.
Apple ProRes 422 (LT) is ideal for live multi-camera and on-location productions where large amounts of footage are acquired to disk. The low data rate of Apple ProRes 422 (LT) also makes it an excellent choice for transcoding complex camera codecs like AVCHD.
• Apple ProRes 422 (Proxy): The third new member of the Apple ProRes family is Apple ProRes 422 (Proxy). This codec maintains HD data rates below 36 Mbps, yet like its higher-rate Apple ProRes 422 siblings, it supports full-frame, 10-bit, 4:2:2 video.
Apple ProRes 422 (Proxy) is intended for draft-mode or preview uses where low data rates are required, yet full-resolution video is desired. It is the ideal format for use in offline editing workflows with Final Cut Server. The traditional offline-to-online workflow with Final Cut Pro has relied on the Offline RT codec, but today’s HD workflows demand offline video formats that support native frame size and aspect ratio. Apple ProRes 422 (Proxy) supports full 1920 x 1080 and 1280 x 720 resolutions, enabling full HD resolution while editing, and accurate representation of FCP motion effects from the creative stages through finishing.

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Answer 10

Shane Ross

Level 8

43,110 points

Feb 17, 2010 3:31 PM in response to David Bogie Chq-1

Thanks for the shout out David, but when it comes to ProRes 4444, or 4:4:4 color spaces, it's out of my league. 4:2:2 is as high as I go. HDCAM SR, but 4:2:2.
Shane

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Answer 11

r_pears Author

Level 1

10 points

Feb 21, 2010 10:10 AM in response to Shane Ross

I got this to work! Only problem is that I have no idea how. After taking a look at the levels more it looked like ProRes4444 was scaling the video to bring any part of the signal below 0 or above 7Mv into the legal range so nothing was clipped. I was ready to accept this and start digitizing but when I did it was suddenly working fine - no video scaling and it included all of the signal. And this worked consistently for the rest of the day. I'm glad it worked, I just wish I had an explanation. Thanks for all the suggestions.

Oh, I did upgrade my Kona software, however it still wasn't working after that upgrade. There's really no reason why it worked the second time but not earlier in the day.

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Answer 12

Mar 6, 2010 2:11 PM in response to r_pears

Did you ever get to the bottom of this? I'm having the exact same issue.

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Answer 13

Mar 7, 2010 6:26 AM in response to Tom Wolsky

From the ProRes white paper:
• Apple ProRes 4444: < </div>

Ah, RTFM.

bogiesan

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Answer 14

r_pears Author

Level 1

10 points

Mar 10, 2010 9:08 AM in response to DavidMarg

Well I thought I was done with this but it's come back. Now I'm seeing that my data rates are not as high as they should be. I realize that it's a variable data rate and for 23.98 I should be getting somewhere around 260MB/s however I'm hitting around 180 instead.

I did a test capturing at uncompressed 10-bit RGB and exported to ProRes4444 and this actually put me in the target range. What I don't understand is why capturing ProRes4444 doesn't give me the same results? Any ideas?

This export method isn't ideal because of the export times and I still get that **** density shift. Thanks.

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Answer 15

Mikey M.

Level 4

1,180 points

May 3, 2010 12:22 AM in response to r_pears

In the AJA Control Panel under the CODEC tab, select RGB Level (right most option) to SMPTE. By default it is set to auto, which seems to default to Full Range. Full range clips the luminance to about 20 mV for blacks and ~640 mV for whites. SMPTE settings is 0 mV and 700 mV respectively.

I have brought this up to AJA and they are "on it".

By the way, this has been validated only with ProRes 4444 YUV, not ProRes 4444 RGB. Still working those kinks out.

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