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Panasonic P2HD / DVCPRO HD Camcorders
All AG-HPX and AJ-PX Series camcorders and P2 / P2HD hardware.


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Old December 10th, 2005, 03:19 PM   #16
Barry Wan Kenobi
 
Join Date: Jul 2003
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Quote:
Originally Posted by Greg Boston
I was of the impression that firewire can't support HD data rates. HDV yes, but not full HD such as the DVCPROHD format.
It certainly can -- that was the big announcement a year ago about FCP HD -- desktop editing of firewire-transferred data.
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Old December 10th, 2005, 03:23 PM   #17
Barry Wan Kenobi
 
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Quote:
Originally Posted by Greg Boston
Hey, it's good news to me if this is true but then why do we need all these dedicated capture cards with SDI if firewire can do the job.
You don't. DVCPRO-HD is "just like DV" because it's grounded in the same frame-discrete, constant-bit-rate technology; a simple explanation is that DVCPRO-HD is actually four DV codecs working together to encode a picture with 4x as much resolution as DV. So yes, it is "just like DV", and yes you can transfer it over firewire just like DV.

Transferring DVCPRO-HD over HD-SDI would gain you nothing vs. transferring it over firewire.

But DVCPRO-HD is the only high-def format that has been integrated with firewire (well, HDV obviously, but I'm talking among the established pro formats). No other HD format uses it -- HDCAM, HDCAM SR, D5, etc. You'd need HD-SDI capture boards to capture the other formats, but DVCPRO-HD can work with a regular $29 OHCI firewire card, to a regular 5400 RPM hard disk.
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Old December 10th, 2005, 03:24 PM   #18
Barry Wan Kenobi
 
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Quote:
Originally Posted by Edwin Hernandez
Can the files on a P2 be accessed while the camera is recording on the other card?
No -- it's either in Camera mode, or VCR mode, but not both. Offloading the cards requires it to be in VCR mode.
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Old December 10th, 2005, 06:13 PM   #19
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Barry--Regarding Firewire output of DVCProHD in FCP, I had heard that there was a "recompression" of effects and the image when this happened, and that it was more desirable to go out HD SDI. Is this true?

Also, if editing HD in FCP, what are the options for real-time monitoring on a professional HD monitor (not the computer monitor). Is it necessary to have a separate card to do this? Thanks!

Peter
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Old December 10th, 2005, 11:41 PM   #20
Barry Wan Kenobi
 
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Quote:
Originally Posted by Peter Richardson
Barry--Regarding Firewire output of DVCProHD in FCP, I had heard that there was a "recompression" of effects and the image when this happened, and that it was more desirable to go out HD SDI. Is this true?
Don't know. Can't imagine why it would be. If the data on the timeline is untouched, it should just be written straight back out the firewire port. If it's been modified (color corrected, titles added, effects, etc) then yes it will need to be recompressed.

Quote:
Also, if editing HD in FCP, what are the options for real-time monitoring on a professional HD monitor (not the computer monitor). Is it necessary to have a separate card to do this? Thanks!
Again, some FCP expert will have to weigh in on this, but I believe that yes, you'd need some sort of HD card like a BlackMagic or Kona or something like that.
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Old December 11th, 2005, 12:57 AM   #21
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Thanks Barry. I think the effects or color corrected shots are specifically what I'd heard there would be recompression of, and this seems to be backed up by your post. How bad is this compression? Does anyone know? The idea of editing on a new Intel Powerbook and going straight out of FW800 to a deck is soooooo appealing, would be a shame if the image was seriously compromised.

Peter
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Old December 12th, 2005, 02:39 AM   #22
Barry Wan Kenobi
 
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Quote:
Originally Posted by Peter Richardson
How bad is this compression? Does anyone know?
The demo footage we shot had some areas of titling and dissolves -- we showed the training staff some stuff that was labeled with titles so it'd been back through the codec once, when output to tape for display. Looked very nice. DVCPRO-HD is basically DV compression, so recompression performance depends on the particular implementation of the codec -- some DV codecs can go 10 generations without significant loss to the image, some can't go more than a couple (I believe the Microsoft codec was famous for not being able to handle more than a couple of generations down, whereas the Sony Vegas codec is good for something like 8 to 10). So it will be with DV100 -- each codec will need to be tested for generational performance.

However, it's not really nearly as relevant as it once was -- we used to recompress and go out on DV tape, but in HD I suspect we're going to see acquisition and mastering being done in different codecs -- i.e., acquire in DVCPRO-HD, distribute in WMV9 or H.264 or MPEG-2, etc. So the recompression issue pretty much goes away, as you won't be often recompressing back to the acquisition codec.

Quote:
The idea of editing on a new Intel Powerbook and going straight out of FW800 to a deck is soooooo appealing, would be a shame if the image was seriously compromised.
What we shot and output wasn't compromised at all in any noticeable way. But as a point of correction, you don't need FW800, FW400 does just fine. There's only one deck to go to, the AJ-HD1200A, and it's FW400.
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