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Downconvert/Field Issues-Upper vs Lower?
We’ve been using the following setup:
-We shoot using the Canon XL H1 to tape (HDV) using 24F
-We capture into FCP using a Convergent Design HD-ConnectLE using 1080i DVCProHD 29.97
-We edit a project in HD and then use Kona’s realtime downconverter to output to Beta either letterboxed or center cutNow, after downconverting, it seems like we have field issues due to the conversion of Upper Field dominance in HD to Lower Field in SD. It’s pretty obvious on some graphic moves and even long dissolves that the that the fields are reversed or that something is wrong.
Anyone having this issue and have a remedy? How do people get around the fields being opposite from HD to SD when downconverting?
(There are also other issues with Kona’s downconversion ghosting images. I’ve seen this posted sporadically on the boards and posted about it previously myself. I finally got the time to call their tech support and after much time on the phone, they finally verified that it IS there and is not right. Usually need a big monitor to see this…they didn’t until they did a downconversion displayed on a Plasma. Hopefully an updated drive fixes this soon.)
Thanks for any thoughts!
Kevin
http://www.drawbridge.tv -
29 Replies
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Nobody is downconverting?? These seem like obvious bugs…I can’t imagine we are the only ones having these problems.
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I do this every week and have never had a problem with fields. I have edited in DVCPro HD 1080i and done this with no problems as well. Usually these days I’m using ProRes in HD. But I’ve never seen field problems on the downconvert and these shows are packed with graphics that are moving, so it would be obvious if there were field problems.
Santi -
Hi Kevin,
Have you contacted our support department? They would more than happy to assist you in finding a solution for your issue.
They can reach via email at support@aja.com, or via phone (during business hours, US Pacific Time) at +1 (530) 271-3190.
Thank you,
—
AJA Video Systems
+1 (530) 274-2048 Intl.
(800) 251-4224 US
sales@aja.com -
Sorry, AJA, I already spent 3-4 hours last week with the known downconvert issue. Santi-You are seeing this one, right? AJA acknowledged it when I was on the phone with them.
I’m thinking the interlacing issue might have to do with the 24F…but again, Santi, what is the deal with the upper versus lower? Is it converting the fields on the fly?
Thx.
Kevin
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Hi Kevin,
I have seen some ghosting on lower thirds, but it’s not really severe on my system, almost unnoticeable, And I still think the Kona 3’s downconvert looks cleaner than than the downconvert from an HDW-F500 deck to a Digibeta. But I’m not starting from HDV footage. I’m going from HDCAM and DVCPro HD. I’d assume that the Kona 3 is doing the field conversion in hardware, but I don’t know for sure. Maybe the issues you’re seeing are from the 24F workflow from that Canon camera, but that’s just a guess on my part.
Santi -
Sorry, that came across as obnoxious. AJA support was pretty great last week, though I do hope we hear that they have a fix to that downconvert ghosting soon.
(You can see this even if you do a simple text on a blank colored background in HD. Then, view the downconverted output on a large screen. The text will look ghosted above and below the text…it took AJA a while to see it, but they did once they put it on a large Plasma.)
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Just to be clear, the ghosting images we are seeing have nothing to do with HDV. It does it on the downconvert period, regardless of codec. I even tested uncompressed HD. Also to be clear, this is using the KonaLH. It’s possible it’s not an issue on the Kona 3. We have 3 LHe’s and they all do it…as does the one at AJA tech support.
Yes, I’m starting to think the other interlacing issue might be Canon’s weird-ass 24F! I will call AJA when I have downtime to see what they think on that one.
Thanks!
Kevin
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First off Canon’s 24F mode is not truly 24p, it is a bastardized 24 frame delivery much like the original Cine-Frame mode was on the Sony cameras, it uses a non standard cadence that cannot be extracted with the tools in FCP.
“Just to be clear, the ghosting images we are seeing have nothing to do with HDV. It does it on the downconvert period, regardless of codec. I even tested uncompressed HD.”
Kevin, ever thought it may just be the interlacing of 1080? the” above and below” ghosting reminds me of standard interlace issues and if it took the Tech support guys at aja awhile to find your issue, maybe that could be the reason, since anytime you down convert to sd the image always takes a huge hit. Especially when going from progressive to interlaced delivery.
gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows -
Hey, Gary. Believe me, I’m quite familiar and frustrated with the ole’ 24F. Had I known 2 years ago that 2 years later there still wouldn’t be a deck that supported the camera with 24F, I would never have bought the $9,000 H1. We also have an A1…ugh, Canon really blew this, in my opinion. It’s possible the one interlacing problem is related to this, but I’ll have to test it more.
The ghosting isn’t standard interlacing. It’s a real problem. Text looks horrible…like I said, you can do the simplest way possible: just text on a background at 1080i and then downconvert and look at it on a big monitor. It’s not good. I have faith that AJA will make it right soon. From the lack of others screaming about this :-), I would assume that this is only a Kona LHe bug, too, and not a Kona3 problem.
Thanks.
KW
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I see it on my Kona 2, for what its worth. have not found a workaround.
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