View Full Version : SDI capture:


Barlow Elton
October 22nd, 2006, 10:01 AM
Here's a simple 10 sec. clip from a test shoot, where I was tethered to a G5 with FCP and a Kona card. The shots were captured in the Sheer codec and transcoded to PhotoJPEG @ 75% quality, which yielded a nice 4:2:2 full-raster image, and the bit rate is a mere 76 mbs for a 24p clip.

Thanks for hosting, Chris!


http://media.dvinfo.net/xlh1/Elton/SiblingsSDI10sec.mov

Robert Sanders
October 23rd, 2006, 02:11 PM
These shots beautifully illustrate the camera's full potential by avoiding HDV compression. The 4:2:2 colorspace is definitely superior. There's zero macro-blocking, particularly in the shadow areas of the image. The grain has a nice, subtle, over-all pleasing quality. HDV has a tendency to "smooth" the camera's inherent grain characteristics, which is a shame, because this is one of the best qualities of this camera.

Looking forward to a Cineform implementation.

It should also be noted how nicely PhotoJPEG@75 cuts through the data rates.

Jonas Nystrom
October 24th, 2006, 09:05 AM
Nice, really nice. Is it the 20x lens?

Curtis Rhoads
October 24th, 2006, 11:35 AM
So this is what you were shooting that day!!! Looks good. How many shots were you able to get after setting up?

Barlow Elton
October 24th, 2006, 11:39 AM
Nice, really nice. Is it the 20x lens?

Yes, 20x lens at F 2.8, and not zoomed all that much either (maybe 25-30% tele--I was pretty close to the subjects). Close to sunset conditions with ND still engaged. I wasn't using an external monitor either for focus, just the EVF and "eyeballing it". :)

Curtis: I shot about 15 min. of stuff. Didn't bring a RAID, just captured raw SDI to an internal SATA drive. Couldn't capture all that long as the Sheer lossless codec was over 400 mbs, so I always captured short clips of 3 min. or less on the outer sectors of the drive in order to avoid dropped frames. (kept it mostly unfilled)

Barlow Elton
October 24th, 2006, 11:46 AM
It should also be noted how nicely PhotoJPEG@75 cuts through the data rates.

PhotoJPEG is an interesting codec. In my CU's, the clips would compress to a much lower bit rate, but in wide shots where I had a lot of dense fall colors and foliage and everything in sharp focus, the bit rate @ 75% quality was bumping up to well over 120 mbs. It's really more like a VBR codec, as far as I can tell.

Robert Sanders
October 24th, 2006, 03:58 PM
PhotoJPEG is an interesting codec. In my CU's, the clips would compress to a much lower bit rate, but in wide shots where I had a lot of dense fall colors and foliage and everything in sharp focus, the bit rate @ 75% quality was bumping up to well over 120 mbs. It's really more like a VBR codec, as far as I can tell.

That's a great point Barlow.

Jay Stebbins
October 31st, 2006, 05:58 AM
The Sheer codec, is it just for capturing & archiving or does it edit well in FCP? I was under the impression that it wqas mainly for archiving footage without suffering any loss of quality. Is there more to it?

Thanks,
Jay

Barlow Elton
November 1st, 2006, 12:27 AM
You can edit with it, but it doesn't have RT transitions and effects--at least in FCP. It does render fairly quickly for an HD codec, however.

It's basically uncompressed quality without the insanely high data rate. (although it's not exactly low data rate either)

Antoine Fabi
November 12th, 2006, 11:58 PM
Barlow,

It looks simply amazing, really ! Extremely well defined.
Very impressive low noise level.

Is there any portable solution (reasonably light) to capture this quality ?

Wouldn't it be nice.

Barlow Elton
November 13th, 2006, 01:20 AM
Yes, it would be nice and I think we'll see something (finally!) in the coming months.

Thanks for the comment.

Wes Vasher
November 14th, 2006, 05:10 PM
Barlow, thanks for posting these. I don't see any interlacing in them and am wondering how you achieved that. I see that the frame rate in the movie is 23.98. Did you use 24f?

Barlow Elton
November 15th, 2006, 12:50 AM
Hi Wes,

Yes, I shot and captured 24F live uncompressed signal to a Final Cut Pro workstation equipped with a Kona HD SDI capture card.

I performed a inverse telecine extraction on the footage in order to have a true 24p clip from a 1080i capture. (the H1 automatically adds pulldown frames to 24F for standards compliance)

Wes Vasher
November 15th, 2006, 07:46 AM
Thanks for the reply Barlow. Very impressive footage. Here's another question, hope I'm not bugging you but when you take the G5 on location how do you power it?

Barlow Elton
November 15th, 2006, 08:41 AM
I took a UPS with me, but it was powered from an available outlet with a long extension cord.