Recording uncompessed for keying at DVinfo.net

Go Back   DV Info Net > High Definition Video Acquisition > General HD (720 / 1080) Acquisition

General HD (720 / 1080) Acquisition
Topics about HD production.


Reply
 
Thread Tools Search this Thread
Old April 29th, 2006, 05:11 AM   #1
Regular Crew
 
Join Date: Jun 2004
Location: Germany
Posts: 59
Recording uncompessed for keying

After getting mediocre results from keying xl2 DV footage, Im thinking about getting a videocard that lets me capture uncompressed or just better than DV quality color wise...
Does anyone here do this on a regular basis?
Like with a Decklink?
Does anyone key through the Y/C of the XL2 or his miniDV?
For a friends project, were thinking of renting a HVX200, anyone keying with the component-outs of the HD(V) cameras yet?
Christian Schmitt is offline   Reply With Quote
Old April 29th, 2006, 05:29 PM   #2
Major Player
 
Join Date: Jan 2005
Location: St. John's, NL, Canada
Posts: 416
Well if your talking XL2 then I think HD/HDV acquisition is the wrong forum.

What I've seen done is using an XL1s into a BETAsp deck with good results. Keying was done on an avid Symphony in 4:4:4 uncompressed (captured over analog component). It was explained to me that the colour space made it easier to key even though it had to pass through analog.

A real pro card should show some benefit rather than a cheaper consumer card. Decklink SP or Decklink Extreme seem like good choices. Sorry I haven't used them though so can't tell you what they are like to use.
Keith Wakeham is offline   Reply With Quote
Old April 30th, 2006, 04:59 AM   #3
Regular Crew
 
Join Date: Jun 2004
Location: Germany
Posts: 59
Well,
Im thinking on renting the HVX200, as stated, and record 720p at different framerates and capture directly to a PC...
Just wanted to get some advice on that...
The XL2/s-video way was only loud thinking, more or less...
Christian Schmitt is offline   Reply With Quote
Old April 30th, 2006, 10:54 AM   #4
Sponsor: VASST
 
Join Date: May 2005
Location: New York
Posts: 516
I do chroma key work with my Sony Z1 and Serious Magic Ultra 2 software. I dont use uncompressed but the results are still far better than anything I could key with DV. I think the added resolution of HDV is enough for most situations. Ultra 2 is also an outstanding piece of software. It makes it very easy to get a good key even under band lighting conditions.

You might want to try keying with compressed HDV first and see if you like the results before you jump though hoops to capture uncompressed off the camera. I believe you need a RAID 0 with at least 5 drives to keep up with uncompressed HDV capture so you are talking some serious equipment.

~jr
__________________
Developer: VASST Ultimate S, Scattershot 3D, Mayhem, FASST Apps, and other VASST Software plug-ins
Web Site: www.johnrofrano.com
John Rofrano is offline   Reply With Quote
Old April 30th, 2006, 12:41 PM   #5
Regular Crew
 
Join Date: Jul 2004
Posts: 43
Quote:
Originally Posted by John Rofrano
I do chroma key work with my Sony Z1 and Serious Magic Ultra 2 software. I dont use uncompressed but the results are still far better than anything I could key with DV. I think the added resolution of HDV is enough for most situations. Ultra 2 is also an outstanding piece of software. It makes it very easy to get a good key even under band lighting conditions.

You might want to try keying with compressed HDV first and see if you like the results before you jump though hoops to capture uncompressed off the camera. I believe you need a RAID 0 with at least 5 drives to keep up with uncompressed HDV capture so you are talking some serious equipment.

~jr
im also trying to get more info on capturing from component of the fx1, as John said capturing uncompress HD is an expensive operation, but if we could capture and encode it live to a better codec ,lets say dvcpro HD @ 8bit, the 4:2:2 color space will be great for keying, KONA LH capture card is soppoused to have analog input and output, for PC there is a new codec from DVFILM guys,the raylight that will let dvcpro HD be edited in Vegas, so now theres no need for expensive raid arrays to capture to a better compresion as i belive one could work with dvcpro HD with a good SATA HardDisk as a couple of 300gb HD will give like 12 hours of storage i think maybe 50GB/hour .
Rafael Cruz is offline   Reply With Quote
Old April 30th, 2006, 03:57 PM   #6
Trustee
 
Join Date: Aug 2003
Location: Vancouver BC Canada
Posts: 1,315
In that situation one would have to ask if DVCproHD IS an improvement over HDV? That is a lot of extra cost/effort to go to another highly compressed codec. You will loose resolution by going to DVCproHD. Yes you will get 4:2:2(at a lower resolution), but for example, head to head tests based on the HVX200 using DVCproHD at 4:2:2 did not show any improvement on keying over an HD100 HDV 4:2:0. I would check out SheerVideo by BitJazz or another codec option.
__________________
Damnit Jim, I'm a film maker not a sysytems tech.
Ken Hodson is offline   Reply With Quote
Old April 30th, 2006, 04:52 PM   #7
Regular Crew
 
Join Date: Jun 2004
Location: Germany
Posts: 59
With the HVX I would pobably just record in DVCproHD, no Decklink needed (well, some claim recording to DVCproHD via the component out yields better result...)
I like Kens idea with the SheerVideo codec:
Can I just tell the Decklink what codec to use?
Can I use SheerVideo for the live encoding with a Decklink?
Would I need a maxed out box for this, with latest dualcore proc, maxed Ram, raid setup aso...?
Christian Schmitt is offline   Reply With Quote
Old April 30th, 2006, 07:48 PM   #8
 
Join Date: Jan 2004
Location: Stockton, UT
Posts: 5,648
As Ken pointed out, there is no advantage of DVCProHD over HDV from the JVC HD100u, but I don't believe it's related to DVCProHD, it's related to the difference between significantly resampled pixels vs full raster pixel/no resample. Shooting DVCProHD with a larger imager makes for a more obvious difference, but not as obvious as most folks might think.
To use the Sheer/Bitjazz codec, you'll want a fast RAID more than anything else. The CPU isn't nearly as important as thruput.
__________________
Douglas Spotted Eagle/Spot
Author, producer, composer
Certified Sony Vegas Trainer
http://www.vasst.com
Douglas Spotted Eagle is offline   Reply With Quote
Old April 30th, 2006, 09:50 PM   #9
Regular Crew
 
Join Date: Jul 2004
Posts: 43
Quote:
Originally Posted by Douglas Spotted Eagle
To use the Sheer/Bitjazz codec, you'll want a fast RAID more than anything else. The CPU isn't nearly as important as thruput.
Fast Raid for PC isnt too expensive at all with $79.00 dollars Mainboards with 4 SATA ll conections and $250.00 dollars 500GB SATA ll harddisks, what do you guys think ? is 300mb/sec transfer rate enough to for live capturing of sheer encoded video? but what i would really like to know is if the declink or kona cards can encode live to sheer codec? and how much video time will you get per Harddisk GB? how much of that 300mb/sec will sheer will use ?

65% less space needed than uncompressed video with almost the same quality is a lot. maybe this is getting interesting. ahh and another big question, does the new cards from aja or blackmagic (decklink,xena LH) can capture from the component output?
Rafael Cruz is offline   Reply With Quote
Old May 1st, 2006, 04:57 AM   #10
Regular Crew
 
Join Date: Jun 2004
Location: Germany
Posts: 59
Quote:
Originally Posted by Douglas Spotted Eagle
As Ken pointed out, there is no advantage of DVCProHD over HDV from the JVC HD100u, but I don't believe it's related to DVCProHD, it's related to the difference between significantly resampled pixels vs full raster pixel/no resample. Shooting DVCProHD with a larger imager makes for a more obvious difference, but not as obvious as most folks might think.
To use the Sheer/Bitjazz codec, you'll want a fast RAID more than anything else. The CPU isn't nearly as important as thruput.
So for me this narrows down to two options:
recording DV100 in 720p via firewire OR recording SD uncompressed (well, SheerVideo encoded if possible with the Decklinks/AJAs...?) via analog-out straight to disk.
Which way to go...?
Douglas, there really seems to be some controversy about wether DVCproHD is really better than HDV,
are your observations based on Adam Willts test?
Maybe it is just so hard to believe for me, that 100Mb/s DV100 isnt better than 25Mb/s HDV,
hell, it should be around 4 times the information!
Ive seen good looking footage from maybe all the HD cams outthere,
if this project wouldnt be 95% greenscreen, Id be happy with most cams.
But here the focus becomes so technical that decision making becomes so hard...
Thanks for all the answers so far and please keep on posting!
Christian Schmitt is offline   Reply With Quote
Old May 5th, 2006, 01:47 AM   #11
Inner Circle
 
Join Date: Jan 2006
Posts: 2,290
Quote:
Originally Posted by Ken Hodson
but for example, head to head tests based on the HVX200 using DVCproHD at 4:2:2 did not show any improvement on keying over an HD100 HDV 4:2:0..
did you perform these tests yourself? first time i've heard that and it's not what i would have expected. got any more info?
Brian Luce is offline   Reply With Quote
Old May 5th, 2006, 02:23 AM   #12
 
Join Date: Jan 2004
Location: Stockton, UT
Posts: 5,648
Quote:
Originally Posted by Brian Luce
did you perform these tests yourself? first time i've heard that and it's not what i would have expected. got any more info?
I don't know if Ken tested this himself or is going by posts, but I did the same thing comparing all of the HD cams (Z1, A1, HD100, XL-H1, HVX200).
Same results as Ken comments upon.
In fact, there is a mask image in my book on HDV showing the key from a Z1. It's visibly smoother/less aliased than the same mask image from the HVX.

While packaged in a 4:2:2 DVCProHD stream, the image is so starved, it's garnering significantly less chroma and luma well before it's being processed.
JVC=1280 x 720 full raster imager/sample
HVX=720 x 540 imager/pixelshifted to 1280 x 720
PAL DV=720 x 576 full raster imager
__________________
Douglas Spotted Eagle/Spot
Author, producer, composer
Certified Sony Vegas Trainer
http://www.vasst.com
Douglas Spotted Eagle is offline   Reply With Quote
Old May 5th, 2006, 12:44 PM   #13
Trustee
 
Join Date: Aug 2003
Location: Vancouver BC Canada
Posts: 1,315
Yes I am just going off of various user reports/posts. I have only used JVC HDV myself. Here is a current article comparing both cams with a specific test using blue screen.
http://www.bluesky-web.com/HDVHVX.htm
__________________
Damnit Jim, I'm a film maker not a sysytems tech.
Ken Hodson is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > High Definition Video Acquisition > General HD (720 / 1080) Acquisition

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 10:01 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network