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Daniel Doherty
Ki Pro and EX3
on Apr 5, 2010 at 2:23:36 am

Hello,
I was recently informed that there was nothing to be gained by recording out of the SDI (EX3) into the Ki Pro due to the PSNR; 54db in EX3. In other words, nothing to be gained by recording 10bit ProResHQ. Any truth to this? Please forgive my ignorance.

Thanks, Daniel


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gary adcock
Re: Ki Pro and EX3
on Apr 5, 2010 at 12:26:06 pm

[Daniel Doherty] "In other words, nothing to be gained by recording 10bit ProResHQ. Any truth to this? Please forgive my ignorance. "

Daniel,
it is actually an excellent question and a point of confusion for most.

The vast majority of cameras on the market today do not compress the video signal as it passes thru the camera. Recording that signal in to a device like the KiPro allows you an amazing amount of the quality in the 10bit, 4:2:2, IFrame recorded signal as Apple ProRes, Apples highest quality codec.

While that EX3 can record a very good image and signal at the 35Mbs setting, it is still limited to 8bit, 4:2:0, LONG GOP Mpeg2 material on the SxS cards that will need to be additionally processed by Final Cut.


You are correct, recording the signal direct from the camera will give you a better picture and an easier edit in my opinion.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows for the Digitally Inclined
Chicago, IL

http://blogs.creativecow.net/24640



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Daniel Doherty
Re: Ki Pro and EX3
on Apr 5, 2010 at 6:52:29 pm

Gary,
Thank you for your response. The advantages you listed are the reasons why I purchased the KiPro. I thought it would compliment the EX3 nicley.

Although I did not phrase it very well, my question was more specific. I was referring to the advantages of 10bit (ProResHQ) vs. 8bit (100/mb Long GOP). It has been stated, by very knowledgeable people, that ProRes will actually add NOISE to the EX3 footage due to the high signal to noise ratio. It was also stated that you would need a camera with 60db or above to benefit from 10bit recordings; the EX3 is at 54db.

You may be saying to yourself, why don't you test it yourself you lazy bum. I have tested it using the difference blending mode in FCP and I did not see any "new" noise. However, I am aware that my monitor (apple cinema display) may not be the most accurate representation of the image.

Does this make any sense to you and have you encountered a scenario where ProResHQ added noise to footage such as an EX3/1?

Thank you for your time,
Daniel


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gary adcock
Re: Ki Pro and EX3
on Apr 5, 2010 at 8:25:58 pm

[Daniel Doherty] "It has been stated, by very knowledgeable people, that ProRes will actually add NOISE to the EX3 footage due to the high signal to noise ratio. It was also stated that you would need a camera with 60db or above to benefit from 10bit recordings; the EX3 is at 54db."

Daniel,
That would not be my experience when recording a Live signal, I have seen the mpeg artifacts when there are poorly done software only conversion.

While ProRes is a compressed codec, I have not ever seen the ProRes codec ever "add noise" to an image. I have tested the standard and HQ ProRes flavors in as many ways and as much as anyone else has and I have never seen additional noise happen during a capture, not once.

Now I have seen compression artifacts in the lower bit rate versions (LT and Proxy) that could be mistaken for noise, but are not when presented on a waveform via HDSDI- a trained eye can see the difference between compression artifacts and gain in the SNR.

As to needing a camera with 60db SNR to gain from a 10bit recording, that would leave out nearly all of the "Pro Cameras" available today - especially when you consider that f900s, Varicams, LDK studio cameras and most other sub $100,000 USD cameras do not have PSNR ratings of 54db.
( I did a very quick check and I could not find one camera that had that high a number that did not shoot 4:4:4)

In all honesty, it gets down to a couple of things- what do you loose when capturing

- when capturing a live signal with the 145Mb standard version of ProRes is 1/4 the amount of data compression (mathematically) that is placed on the SxS codec 35Mb version, and your video stays I-frame rather than using a 15 frame long gop structure and it stays as the original 10bit signal coming out of the side of the camera.


Maybe your "expert" does not want to work in ProRes because he works on an Avid??







gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows for the Digitally Inclined
Chicago, IL

http://blogs.creativecow.net/24640



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Daniel Doherty
Re: Ki Pro and EX3
on Apr 5, 2010 at 11:33:05 pm

Gary,

Thanks again for setting my mind at ease.


-Daniel


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Tim Kolb
Re: Ki Pro and EX3
on Apr 6, 2010 at 5:25:00 pm

Hi Daniel...

That thread on that other site got into a lot of theory for sure...not all of us were exactly in the same camp on this...

Also, keep in mind that there were many variations that were being compared. I think that a KiPro at 220 Mbit HQ is far better than 35 Mbit EXcam without a doubt.

That conversation ended up branching out into 8 bit vs 10 bit in general...4:2:0 vs 4:2:2 ended up getting confusing because we had someone who was advocating an external box that does high bitrate 8 bit 4:2:2...which is not 35 Mbit 4:2:0...it started as an apples and oranges conversation and ended up apples and airplanes.





TimK,
Director, Consultant
Kolb Productions,


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Daniel Doherty
Re: Ki Pro and EX3
on Apr 6, 2010 at 11:35:06 pm

Hello Tim,

Yes indeed, that thread was quite confusing. Admittedly, I am still a bit confused. I originally asked Gary if he had ever witnessed ProRes "add" noise to footage. He said never. Then, on the other site, it was said that compressed 10bit 4:2:2 could accentuate noise (or represent more faithfully) in a lower end camera (EX3).

Was that a reference to Pro ResHQ or ProRes...or all of the above?

Have you ever been witness to ProResHQ "accentuating" noise in an EX3/1?

Does that mean that 10bit ProRes HQ has no benefit over 8bit Long GOP at 100Mb?


Thanks for helping to clarify,

Daniel



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Tim Kolb
Re: Ki Pro and EX3
on Apr 7, 2010 at 3:24:19 am

Well...again, we're changing comparisons.

The EX3 native is 4:2:0, 35 Mbit, 8 bit Long GOP.

The 100 Mbit Long GOP typically referred to is a 4:2:2 format that has 3 times the data rate and better color subsampling...it's not what the EX3 records native, so it simply clouds the discussion that you started in the subject line.

100 Mbit/s, 4:2:2, Long GOP is far better than 35 Mbit/s, 4:2:0 Long GOP...

I've done some testing with the KiPro and also some other external data recorders...I want to do more testing before I'd have any opinions anywhere as strong as the opinions expressed in that thread...(I've only used ProRes HQ...no other bitrates).

Clearly though, 10 bit is just a lot more color precision...there is more information in 220 Mbps, 10 bit 4:2:2 material than 35 Mbps 8 bit 4:2:0. However, Long GOP is more efficient than I-frame...so data rate isn't the whole story...but it's a huuuge gap we're talking about here, and Long GOP doesn't close to filling the gap when you consider all the technical factors between EXcam and ProRes HQ.

What is noise and what is extra detail...and what is compression artifact is difficult enough to determine when you're looking at it yourself. It's impossible when somebody is trying to describe it in written form when the content of the image, the camera settings, and the display being used to view the material and its calibration are all in question, not to mention we all have different pools of experience that we reference...

Honestly, I always recommend each user conduct their own test in circumstances like this as very few of us can claim complete objectivity.

However, the question in your subject line is really "Is 10 bit ProRes higher in image quality than 8 bit XDcamEX?" and the short answer is that yes, it is...



TimK,
Director, Consultant
Kolb Productions,


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Daniel Doherty
Re: Ki Pro and EX3
on Apr 7, 2010 at 5:32:35 am

Tim,

I debated and researched for six months before I bought the KiPro. I am well aware of the differences between 100Mb Long GOP and 35Mb Long GOP. I finally settled on the KiPro due to the 10bit nature of the codec versus the 8bit codec in the other product I was considering.

Due to my confusion, my original post was inaccurate. Therefore, I corrected it in my second post by comparing ProResHQ to 100Mb Long GOP. Sometimes it's hard to find the right question to ask when you're confused.

I have been lurking on these forums for quite some time. In fact, I've become addicted to the flow of information. My girlfriend thinks I need to seek professional help. Although it does help that she has a Masters in Clinical Psychology.

I respect the fact that others are more knowledgeable than I and I appreciate how selflessly that information is passed down. It only becomes difficult when contradictions arise.

Thank you for your time,
Daniel


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gary adcock
Re: Ki Pro and EX3
on Apr 7, 2010 at 4:04:32 pm

[Daniel Doherty] "I respect the fact that others are more knowledgeable than I and I appreciate how selflessly that information is passed down. It only becomes difficult when contradictions arise.
"


I could not agree more, if you really want a good time you should see people like Tim and I do this Live and In person at the bar.
It is far more engaging that way and a helluva lot more fun too.



gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows for the Digitally Inclined
Chicago, IL

http://blogs.creativecow.net/24640



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Tim Kolb
Re: Ki Pro and EX3
on Apr 7, 2010 at 10:16:49 pm

[gary adcock] "I could not agree more, if you really want a good time you should see people like Tim and I do this Live and In person at the bar."

Some of my favorite time spent... :-)

See you at NAB, Gary. I'll be in Saturday night.






TimK,
Director, Consultant
Kolb Productions,


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gary adcock
Re: Ki Pro and EX3
on Apr 8, 2010 at 2:09:18 am

[Tim Kolb] "See you at NAB, Gary. I'll be in Saturday night.
"


already here.

Stopped in LA first for the ARRI Alexa launch event on Tuesday.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows for the Digitally Inclined
Chicago, IL

http://blogs.creativecow.net/24640



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Daniel Doherty
Re: Ki Pro and EX3
on Apr 8, 2010 at 12:38:48 am

Gary, at least it's safer than talking about politics.



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gary adcock
Re: Ki Pro and EX3
on Apr 8, 2010 at 2:12:40 am

[Daniel Doherty] "at least it's safer than talking about politics.
"


Who are you kidding?

We are talking about religion here...

Mac vs. PC.
Avid vs. Apple vs. Adobe
2D vs. 3D



gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows for the Digitally Inclined
Chicago, IL

http://blogs.creativecow.net/24640



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Tim Kolb
Re: Ki Pro and EX3
on Apr 8, 2010 at 3:18:25 am

[gary adcock] "Who are you kidding?

We are talking about religion here..."


Boy...THAT is the absolute truth...



TimK,
Director, Consultant
Kolb Productions,


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Daniel Doherty
Re: Ki Pro and EX3
on Apr 9, 2010 at 2:46:39 am

[Gary]"We are talking about religion here..."


I actually laughed out loud when I read this...Good one Gary.


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gary adcock
Re: Ki Pro and EX3
on Apr 9, 2010 at 1:14:23 pm


[Daniel Doherty] "I actually laughed out loud when I read this..."

I'm glad, that was the point.


One more note for your battle here, Tell me you have seen that ARRI has announced that ProRes will be the default internal recording medium for their New Top of the Line Alexa Camera model.

So if ProRes is good enough for the premier name in FILM Cameras, maybe those people tell you that ProRes is not good enough need to re-thing their bias towards that codec. Arri could have done anything even create a new compression standard, but they chose ProRes.


gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows for the Digitally Inclined
Chicago, IL

http://blogs.creativecow.net/24640



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Daniel Doherty
Re: Ki Pro and EX3
on Apr 9, 2010 at 3:09:36 pm

I read about the ARRI ALEXA yesterday and, I must say, it put a smile on my face.


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