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Kona 3 Downconvert settings and reference

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Daniel Miller
Kona 3 Downconvert settings and reference
on Jun 23, 2008 at 4:22:09 pm

I have some 720p 23.98 footage that I need to lay off to digibeta. I just want to make sure Im setting up the Kona right before I really get going on this job.

From what I understand I should have my frame buffer set to the same as my sequence (720p 23.98) and my output set to 525i 29.97. However, it wont let me go from 720p 23.98 to 525i 29.97. It WILL let me go from 720p 59.94 to 525i 29.92 and since I can play my 23.98 stuff in a 59.94 sequence it stands to reason that I can set my frame buffer to 59.94. It then gives me the downconvert icon in the output line. I should also be feeding 59.94 reference to my kona and to my digibeta deck.

If Im off please let me know, Thanks for your time.


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Jeremy Garchow
Re: Kona 3 Downconvert settings and reference
on Jun 23, 2008 at 5:49:32 pm

Your timeline should be 23.98.

Choose a 720p 23.98 easy setup that is the same codec as your sequence and has the work Varicam in the title (such as AJA Kona 3 720p23.98 Apple ProResHQ Varicam if you are using ProResHQ in your timeline). The in the control panel choose your secondary output as 525i29.97.

720p23.98 as a frame buffer is an intermediate format only. All 720p23.98 video will get played as 59.94. Then form there get down converted to 29.97 525.

Jeremy


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Daniel Miller
Re: Kona 3 Downconvert settings and reference
on Jun 24, 2008 at 9:41:02 pm

Thanks Jeremy, that worked perfectly.

However, I am here with another similar question. This time i have 720p 23.98 dvcpro hd material. I need to cross convert to hdcam sr 23.98. I set my frame buffer to the same as my sequence (23.98) and my secondary output to 1080psf23.98. I send 23.98 reference to my kona and sr deck. When I edit to tape I just get a gray screen. The sound comes through, but no video. Just for giggles I used the easy setup menu and set it to 1080sf 23.98 dvcpro hd. I layed in my footage to the timeline and it automatically switched to 720p, however NOW the sr deck is getting the signal. needless to say I was confused and a little annoyed. Is that the normal way things should be done? Ive looked all through the kona 3 user manual trying to find the best way to do this and it doesnt really go into a lot of detail, unless I was just looking in the wrong place.



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Jeremy Garchow
Re: Kona 3 Downconvert settings and reference
on Jun 24, 2008 at 10:09:54 pm

Are you recording dual link to SR?


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Daniel Miller
Re: Kona 3 Downconvert settings and reference
on Jun 24, 2008 at 10:21:00 pm

No.

I have the SR system settings setup for 1080psf 23.98 4:2:2. I realize I didn't say that earlier.



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Jeremy Garchow
Re: Kona 3 Downconvert settings and reference
on Jun 24, 2008 at 10:30:57 pm

Cool, just had to be sure. Your timeline is 720p23.98. Then what you need to do is go to the View menu and choose View > VIdeo Playback > AJA Kona 720p23.98 8bit.

Then makes sure your frame buffer is set to 23.98 in the control panel and your secondary is set to 1080sf23.98 and choose the secondary output on the SDI output that connected to the SR deck. Should be good then.

Jeremy


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Daniel Miller
Re: Kona 3 Downconvert settings and reference
on Jun 24, 2008 at 10:44:32 pm

Yeah, thats how I had it originally configured. I just reset it using your guide lines and Its all borked again. What reference should I be feeding to the kona? 23.98?

I mean, I got the job done, I just want to know how to properly set this thing up in the future, and for my own piece of mind. Thanks for your time man, I appreciate it.



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Jeremy Garchow
Re: Kona 3 Downconvert settings and reference
on Jun 25, 2008 at 4:08:38 am

What you are trying to do is two separate conversions that make different use of the Kona card and are also two different time bases. You ultimate end conversions have 23.976 frames and 59.94 fields in HD and SD respectively).

So when going from 720p23.98 to 525i29.97 (or 59.94 fields) the signal gets converted to 720p59.94 first, then gets down converted to 525i29.97 (59.94). The time base is then the same. So in order to do this you need to tell the Kona to first convert to 59.94 (which is what the frame buffer does @ 59.94 as 720p video can only get played out to a monitor @ 59.94) then down convert to SD.

When cross converting from 720p23.98 to 1080psf23.98 you are keeping the same time base of 23.976 frames per second. In that case you keep the frame buffer @ 23.98 720p which acts as an intermediate format only as this format will not get played out to a monitor as no monitor will support 720p23.98 as it's a format that exists only on our hard drives. So then, you tell the Kona to take the 23.98 material and cross convert it to 1080sf23.98 which is then a valid SMPTE signal which almost all HD monitors will understand.

So when going from 720p23.98 to 525, use the easy setup with the Varicam in the title of it (as that ultimately goes to 59.94).

When going from 720p23.98 to 1080sf23.98, use the 23.98 easy setup with no Varicam in the title. That will ensure that you are sending the right time base to ultimately get converted.

Hope all that makes sense. If it doesn't, please post back and I'll explain it further.

Jeremy




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Daniel Miller
Re: Kona 3 Downconvert settings and reference
on Jun 25, 2008 at 8:40:45 pm

Thanks Jeremy, Im following everything you said, and its making sense. It just seems like the Kona 3 is a little finicky sometimes. Thanks for your time, it helped alot.



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Jeremy Garchow
Re: Kona 3 Downconvert settings and reference
on Jun 25, 2008 at 9:02:30 pm

[Daniel Miller] "It just seems like the Kona 3 is a little finicky sometimes."

In this case, the only thing it's not doing is converting your 720p23.98 timecode to 59.94 timecode. It can't do everything. But it will go from 720p to 1080psf 23.98 so at least you got that! ;)

Jeremy


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