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Old November 1st, 2009, 07:13 PM   #1
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Uncompressed from HM700?

Has anyone captured footage from the HM700 via the HDSDI output? Possibly to a NanoFlash or AJA KI Pro or directly to a computer via one of the popular SDI capture cards?

Just wondering how the noise issues are via that route.
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Old November 2nd, 2009, 02:20 AM   #2
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Bear in mind that these things are still not "uncompressed".
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Old November 2nd, 2009, 03:16 AM   #3
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A live feed from the HD-SDI output can be considered "uncompressed" with respect to the fact that it has not gone through the mpeg2 encoder, however it is still chroma-subsampled to 4:2:2 at 8 bits/pixel.
If you digitize this live signal using an uncompressed codec then (in theory) the resulting media will an exact pixel for pixel clone of the original HD-SDI signal. I have done some tests with the uncompressed codec as well as the Apple ProRes codecs and they are available in the FCP forum.

But what about noise? The mpeg2 encoder isn't actually adding video level noise at the compression stage. Yes there will be added compression artifacts (and chroma is sub-sampled to 4:2:0) but if anything you will probably see slightly less overall noise in the B & R channels after encoding because the of the added amount of subsampling. This difference is negligible and difficult to see even when carefully analyzing the separate channels.

The latest HM700 firmware update addressed noise reduction (among other things) but I have yet to empirically analyze a before and after.
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Old November 2nd, 2009, 05:11 AM   #4
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Tim,
Does all of that also apply to the HM-100? I have asked JVC directly several times with, predictably, no response.
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Old November 2nd, 2009, 06:46 AM   #5
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Tim, I was under the impression the output on the HDSDI is 10bit. Not so?
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Old November 5th, 2009, 07:55 PM   #6
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Quote:
Originally Posted by Paul Shapiro View Post
Tim,
Does all of that also apply to the HM-100? I have asked JVC directly several times with, predictably, no response.
Okay, has ANYONE been able to find this out? Can we get full uncompressed from the HM-100 HDMI?
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Old November 6th, 2009, 12:27 AM   #7
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Paul, I am also interested in the output from the HM100 HDMI port. I am thinking of getting a blackmagic card.

I found this link on the JVC US page.
http://usjvc.com/faq/index.php?actio...123&artlang=en

It states HDMI is produces uncompressed output. I am not sure this is official.
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Old November 6th, 2009, 05:54 AM   #8
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Thanks very much Andy; I overlooked that JVC page. I guess the CD nanoFlash would also be an option. The nano would also add timelapse to the humble HM-100 -- although at quite a price!
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Old November 20th, 2009, 10:51 PM   #9
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Quote:
Originally Posted by Andy Urtusuastegui View Post
Paul, I am also interested in the output from the HM100 HDMI port. I am thinking of getting a blackmagic card.

I found this link on the JVC US page.
JVC Pro FAQ

It states HDMI is produces uncompressed output. I am not sure this is official.
It is official.
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Old November 20th, 2009, 11:23 PM   #10
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Craig, thank you for clarifying this. I am going to move forward with my plans to get a blackmagic card.

Tim, seems this should be in a FAQ or sticky.
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