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AJA Ki Pro Mini prores files lighter than QT's prores files.

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Anthony Huang
AJA Ki Pro Mini prores files lighter than QT's prores files.
on Sep 11, 2011 at 9:00:04 pm

Hello CreativeCow! This is my first post, and I'm happy to finally take part of the forum that has helped me so much in the past!

Anyways, this is more of a curiosity than a request for a solution. I'm currently on a set that is shooting on the Sony F3, which is outputting to the AJA Ki Pro. I've noticed that if I convert the XDCam footage in FCP, QT, or MPEG Streamclip, the footage is a little darker than the prores files that come from the AJA Ki Pro. I tried turning the gamma correction in the QT settings from automatic to none, but the picture looks the same. I'm not too concerned, but obviously this might be give post a small scare. Is there a way to get a prores output in the computer to match the lighter prores output from the AJA Ki Pro?

Thanks for any input! I'm aware that this isn't really an issue because the contrast can easily be matched during color, but I'm still curious!

Thanks again!
Anthony


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Jeremy Garchow
Re: AJA Ki Pro Mini prores files lighter than QT's prores files.
on Sep 12, 2011 at 4:01:54 pm

It's hard to judge the true quality of a QT movie on a computer. What if you put the two ProRes files (one from KiPro, the other that is converted) on the KiPro itself, then playback through a video monitor. Do you notice a difference then?

Have you tried Compressor or other software?


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Anthony Huang
Re: AJA Ki Pro Mini prores files lighter than QT's prores files.
on Sep 12, 2011 at 6:44:58 pm

The only way to transcode the XDCam footage from the Sony F3 in a computer on FCP 7 is to import using Log & Transfer, pulling in your footage as XDCam (Sony hasn't made a L&T plugin that transcodes, just imports and reads), then exporting as Apple ProRes. Compressor, and QT 7, cannot read the .mp4 file inside the BPAV folder.

From what I understand however, all these programs use the same Quicktime function/mechanics that's built into Mac OS X, so they really shouldn't different.

I know that laptop monitors aren't the most accurate monitors to judge color on, but if the ProRes files are suppose to be the same, then they should still look, the same, right? If my monitor was yellow tinted or something, then both clips should just be equally yellow tinted if the files are suppose to be identical, correct?


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Jeremy Garchow
Re: AJA Ki Pro Mini prores files lighter than QT's prores files.
on Sep 12, 2011 at 7:01:01 pm

[Anthony Huang] " Compressor, and QT 7, cannot read the .mp4 file inside the BPAV folder."

So you can transcode the the log and transferred footage, or buy a QT component such as MXF4mac to make the MXF or cinemon to make the mp4 available to the OS.

[Anthony Huang] "From what I understand however, all these programs use the same Quicktime function/mechanics that's built into Mac OS X, so they really shouldn't different. "

Kinda. They are not all created equally. They might be different.

[Anthony Huang] "I know that laptop monitors aren't the most accurate monitors to judge color on, but if the ProRes files are suppose to be the same, then they should still look, the same, right?"

It really depends. Sometimes the flags are incorrectly written or displayed in QT. The only way to really be sure is to watch the video though a proper hardware device and a broadcast monitor to ensure what you are seeing is true.

[Anthony Huang] "If my monitor was yellow tinted or something, then both clips should just be equally yellow tinted if the files are suppose to be identical, correct?"

It's not all about color, it is about gamma and color space, both if which can get lost on a computer display.

Jeremy


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Anthony Huang
Re: AJA Ki Pro Mini prores files lighter than QT's prores files.
on Sep 12, 2011 at 7:37:29 pm

I guess what I'm suggesting is, if I were to transcode footage in FCP to Apple ProRes, and say, footage in MPEG Streamclip, on my laptop, and if I opened the files in QT 7, put the ProRes files side by side, they would look the same, because they're identical, regardless of whatever contrast or gamma or tint inaccuracies existed on my laptop screen. A broadcast monitor would indeed display accurate colors, but the files would still look the same because they're identical. My laptop screen is the consistent factor in viewing these files.

But the ProRes files that comes out of the AJA Ki Pro are lighter. Is there some setting within the Ki Pro that should be looked at? Is there a gamma setting that should be set different from default? Is this the result of recording SDI as opposed to HDMI? I believe the only option to play with on the AJA Ki Pro is what kind of Apple ProRes file you want.


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Jeremy Garchow
Re: AJA Ki Pro Mini prores files lighter than QT's prores files.
on Sep 12, 2011 at 7:57:50 pm

[Anthony Huang] " but the files would still look the same because they're identical."

Are they, really? There is the OS and the gamma and color flags that are in the file. If those are written incorrectly, your laptop won't display them correctly. The only way to be sure is to display your files through proper hardware and a broadcast monitor, sorry. You can also use Digital Rebellion's Pro Media Tools to compare settings: http://www.digitalrebellion.com/promedia/ but it still won't make up for proper monitoring.

What might look different on your computer, might look the same on a proper setup as everything will displayed as intended and not bastardized by the OS.

[Anthony Huang] "But the ProRes files that comes out of the AJA Ki Pro are lighter. Is there some setting within the Ki Pro that should be looked at?"

No. There are no settings to change. My guess is that the gamma setting is off in your compressed files, or it is simply displaying in correctly on your computer monitor. I can not stress how important it is to monitor your files correctly, and your computer is not the right way to do this.


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Douglas Villalba
Re: AJA Ki Pro Mini prores files lighter than QT's prores files.
on Oct 15, 2011 at 12:47:34 am

Something to have in mind is that the F3 internal recording is 8 bit 420 and KiPro is 10 bit 422.

Douglas Villalba

http://www.advertising-villa.com

info@dvtvproductions.com


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Anthony Huang
Re: AJA Ki Pro Mini prores files lighter than QT's prores files.
on Oct 15, 2011 at 1:39:35 am

Sorry for not posting the solution to this earlier!

Yes, the AJA Ki Pro is 10 bit 422. This is possible because the video output on the Sony F3 is 10 bit 422. This is why many opt for the AJA Ki Pro on this camera. The XDCam files, as mentioned by Douglas, is 8 bit 420. There is literally less information, less color, and therefore, explains why the image is so different. Thanks everyone for your help and input! Greatly appreciated!


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