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DVCPRO HD - Firewire vs Kona vs Decklink

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Shane Ross
DVCPRO HD - Firewire vs Kona vs Decklink
on Aug 20, 2007 at 9:20:18 pm

This test stems from this thread:

http://forums.creativecow.net/readpost/98/866320?pview=t#head

OK...in short, I captured DVCPRO HD 720p 23.98 footage in three ways: via firewire, with a Decklink Multibridge Pro and with a Kona LH. The Kona and Decklink captures were done via HD SDI using their DVCPRO HD 720p 23.98 settings. ALL THREE captures worked on a DVCPRO HD 720p 23.98 timeline without rendering. And I could view the Decklink capture on my machine with the Kona card and NO Decklink drivers, and I could view the Kona capture on the system with the Decklink and NO AJA drivers.

To me, viewing on my PVM-14L5 CRT monitor...I could NOT tell the difference. They looked exactly the same to me.

Interesting notes...the two files captured with capture cards have slightly different data rates. The Firewire one is 5.7MB/s, the Kona one is 5.8MB/s and the Decklink file is 5.5MB/s. The file sizes for them vary as well. The Decklink one is 4.52 for the entire 14:34 capture...Kona is 4.75GB...and I am not sure about the firewire one for there was a couple breaks due to CADENCE. But it is roughly 4.7GB. SO the Decklink capture (same IN and OUTs) takes up less space.

OK...now to let you all just look at them and see for yourself:

http://pistolerapost2.com/shaneross/

The clips are 20 seconds long, and are 4 sample shots. Then I have one file - CHURCH_Grad-Sky that consists of all three. First sample is Firewire...second shot is the same one, KONA codec...and the last is Decklink. Mainly for you too see how they all handled the BLUE of the sky, since BLUE is the highest compressed color in DVCPRO HD.

But, since I have them all on one timeline, and exported out as a self contained MOVIE...is that tainting the test? I figured since I didn't render anything, it wouldn't...and you only want to look at the footage.

Whatever...there they are...talk amongst yourselves.

(should I cross post this on FCP?)



Shane

Littlefrog Post
http://www.lfhd.net


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gary adcock
Re: DVCPRO HD - Firewire vs Kona vs Decklink
on Aug 20, 2007 at 9:43:13 pm

[Shane Ross] "eresting notes...the two files captured with capture cards have slightly different data rates. The Firewire one is 5.7MB/s, the Kona one is 5.8MB/s and the Decklink file is 5.5MB/s. The file sizes for them vary as well. "

Check the number of audio tracks
my guess is the Kona captured more tracks of audio (default) than the decklink did, hence the larger file size.


the best test I can think of is laying stills of all three captures over the top of one another and use the difference mode in photoshop to show the differences. Think of Marco's tests.

Should do a 8bit UC also as a base line





gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows


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Shane Ross
Re: DVCPRO HD - Firewire vs Kona vs Decklink
on Aug 20, 2007 at 9:53:25 pm

DOH! I just noticed that the Decklink capture DID NOT INCLUDE AUDIO. So, there...solved THAT mystery. Thanks Gary.

I did do an 8-bit uncompressed capture as well (testing a Raid unit)...so I can upload footage from that as well.



Shane

Littlefrog Post
http://www.lfhd.net


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Christopher S. Johnson
Re: DVCPRO HD - Firewire vs Kona vs Decklink
on Aug 28, 2007 at 4:03:08 am


Right and besides quality, we were looking for compatibility. We were worried that we would get a dark green RT bar above clips if we cross pollinated from different cards.

Sounds like that doesnt happen. Cool.

-Christopher S. Johnson


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