Dual Link HD-SDI
 

Dan and Mike,

Congratulations on the linked nanos for 3D recording. Quite a feat!

I was wondering — blue-sky, I don't really know much about the technical side of this — but does this have any implications for Dual Link HD-SDI recording?

Jeff

Hi Jeff, I also have a dual link SDI camera and I'm pretty sure that the Nano will not sync to a leg of a dual link output. I can test this tomorrow to be sure.

Cool. What I'm wondering is if a 3-D nano could be used to record both legs of a Dual Link HD-SDI signal.

Not that I have such a camera.

Just curious.

Jeff

Out of a Double Link you don't get 2 single Link. The stream you get, is nothing that the NANO can manage.
The 3D NANO is basically two NANOs in sync, recording from two different SDI.
rafael

I'd rather see the nano supporting the 3G HD-SDI than dual link with two nanos.

I am not quite sure how dual link works. Does it split a 4:4:4 stream into two complementary 4:2:2 streams? If so, you should probably be able to use two nanos to record the dual link into two single link recordings, each compressed separately. Though, combining the two separate 4:2:2 files into a single 4:4:4 file would be a challenge.

Adam, one stream 4:2:2 the other 0:2:2

Smpte 372m
 

FYI:

HD-SDI Standards
Standard Name Bitrates Example Video Formats
SMPTE 372M Dual Link HD-SDI 2.970 Gbit/s, and 2.970/1.001 Gbit/s 1080p

For very high-definition applications, requiring greater resolution, frame rate, or color fidelity than the HD-SDI interface can provide, the SMPTE 372M standard defines the dual link interface. As the name suggests, this interface consists of two SMPTE 292M interconnects operating in parallel. In particular, the dual link interface supports 10-bit, 4:2:2, 1080P formats at frame rates of 60 Hz, 59.94 Hz, and 50 Hz, as well as 12-bit color depth, RGB encoding, and 4:4:4 colour sampling.

Cheers—

Jeff

Thanks, Bruce.

This is pure science fiction.
rafael

Well on my camera single link 4:2:2 SDI is encoded with YCrCB, which the nano works fine with. My camera's 4:4:4 dual link is RGB encoded. I don't think that will work with Nano.

No need to be rude. I clearly stated I did not know how it worked. Bruce's reply was much more constructive and up to the point.

AJA Kona 3 does it...
 

...the AJA Kona 3 (I believe all Kona boards) could capture Dual Link HD-SDI. There are 2 SDI connectors on the BOB. I understand that the RED cameras are Dual Link HD-SDI capable.

Jeff

Dear Jeff,

We have not included Dual-Link HD-SDI recording in our current plans for nano3D.

For one, we had not thought of this.

Dan,

Pardon me for going off on such a tangent with this Dual-Link stuff, but the Nano 3-D got me thinking "blue sky." I would be very interested to hear from you or Mike as to whether or not this is even possible with a couple of Nanos. I was really impressed that you have them synchronized, and that got me started thinking...

I used to run a small software company, and we specialized in VTR control. If you ever control an RS-232, RS-422, or FireWire deck in Final Cut Pro, you're using our software. At one time (1996 or so), we had code that turned your desktop NLE into a DDR. We even had a 2 machine, frame-accurate, cuts-only editor waaaaaaaay back when. The last two products did not fly, but the knowledge gained in creating them was invaluable, and applied to other products.

All the best,

Jeff

Adam,
Sorry if I sound rude. Wasn't that my intention.

This is from Wikipedia:
"In the case of 1080p60, 59.94, or 50 Hz video over a dual link; each link contains a valid 1080i signal at the same field rate. The first link contains the 1st, 3rd, and 5th lines of odd fields and the 2nd, 4th, 6th, etc. lines of even fields, and the second link contains the even lines on the odd fields, and the odd lines on the even fields. When the two links are combined, the result is a progressive-scan picture at the higher frame rate".
If this is correct, with a 1080p60/50, each SDI could be recorded in a NANO.
The two stream could be recombined with the proper software.
Rafael

I found this note as well:

"Note that the data layout in dual link is designed so that the primary link can be fed into a single-link interface, and still produce usable (though somewhat degraded) video.

The secondary link generally contains things like additional LSBs (in 12-bit formats), non-cosited samples in 4:4:4 sampled video (so that the primary link is still valid 4:2:2), and alpha or data channels. If the second link of a 1080P dual link configuration is absent, the first link still contains a valid 1080i signal."
If what I pasted in the other post is true, probably that note is about 444 RGB, while this one is about 444 YUV. 422 RGB it doesn't exist.
rafael

I stand corrected. I configure my camera for 4:4:4 dual link HD-SDI output. I took the dual-link SDI on my camera and used HD-SDI (1) - synced just fine and recorded it just fine. I then connected to the HD-SDI (2) and it also recorded just fine and synced just fine.

This leads me to think that two boxes could in fact be used to record a dual link signal. Now if it could be done in full 10 or 12 bits, that would be remarkable indeed.

Matter of fact, if there were a way to combine the two images, and sync the two XDR together, I think I'd buy another one. Yeah, I would.

The plot thickens...
 

Aaron,

Couldn't an AJA Kona board handle the combining of the two legs? It would mean that you would have to play the video out in real time, capturing through the Kona as if it were being fed by a VTR.

I'm getting ready to dump my first generation Kona 2, but I see that Kona 3 still boasts Dual Link capability. Leads me to the question: how many folks with Kona boards ever actually used Dual Link input?

I've also begun wondering about the nanoFlash's potential as a DDR, and whether or not it might (with some work, of course) be controllable by RS-422 protocol.

Interesting, fun stuff to consider...

Jeff

Interesting points Jeff. If I had a Kona card, I'd be using dual link input everyday since may camera has dual link output. Not sure how many people use it though.

I was thinking more of a software method to combine the two seperate recordings of single link from a dual link source. Playing them back on the XDR or Nano doesn't provide me with any comfort level at all. These boxes have been proven to have severe playback problems. Maybe once they are made to be reliable playback boxes, this would work.

This has me even more curious now though. In order to test it, I'd need another XDR, a way to sync them up for recording and locked playback, a PC, a kona card, a RAID. I guess I'd need a lot of stuff.

I really would like to know if it would work though. At a price of around $8500 for two XDRs, it would be the lowest priced portable 4:4:4 recorder that I know of.

To be really useful though, the RS-422 port would need to be active, another feature that I'm not counting on anytime soon.

As I see the things, it would be a possibility of recording 1080p60/50 YUV 422.
No 444 RGB or YUV.
In 1080p60/50 YUV 422 its seems that each SDI output a 1080p30/25 stream. One the odd frames the other the even frames.
If you are able to record those two streams (Intraframe recording) combine the would be really easy with AE.
You don't need two NANOs to test if this is feasible.
Try one SDI at the time. See if you are able to record anything.
rafael

I noticed you said you have a dual-link SDI (SMPTE 372M) compatible camera, what kind of camera is it. I have been trying to find a link to all the professional camcorders that support SMPTE 372M or SMPTE 424M with zero luck.

Dear Douglas,

Arron has a Thomson Viper.

Dan is correct, it is a Thomson Viper. Since my original post, I did in fact purchase a 4:4:4 recorder and I now use that recorder when I record 4:4:4 dual link, and I use my Convergent Design recorder when I want to record 8bit 4:2:2.

You'd be surprised how often 8bit 4:2:2 is really all you need, although it's nice to have the option to do either.

A Camera Worth Higher Color Precision
 

....Hi Aaron: I'm sure that a Thompson Viper is worthy of at least 10 bit minimum color precision ;-) Although I'm sure the XDR clips look utterly amazing !

Thanks for your guys answers.

I just noticed while looking through the user manual for the Viper the following supported formats:

The following formats can be selected in the Install menu:
1080psf at 23.98Hz
1080psf at 24Hz
1080psf at 25Hz
1080psf at 29.97Hz
1080i at 50Hz
1080i at 59.94Hz
1080i at 59.94Hz - 23
720p at 23.98Hz
720p at 25Hz
720p at 29.97Hz
720p at 50Hz
720p at 59.94Hz

What really surprised me was that even with the dual link data transfer rate the Viper doesn't appear to offer 1080p at 59.94Hz? I must have had the wrong impression about the reason for dual-link SDI to start with. I though it was introduced to be able to support the 1080p 60fps data rate. I'm seeing this isn't stricly true. Obviously the quality you must be getting is really incredible even at 1080i so I guess it's not really a problem. Since it looks like this camera is a Digital Cineman camera your probably shooting at 720p @ 24fps.

One thing I did notice when looking at some specs for SMPTE 424M standard is that it does mention it supports the 1080p @60fps data rate. In addition of course it offeres the dual-link SDI data rate to be transmitted through a single SDI cable at 1080p @ 60fps
http://en.wikipedia.org/wiki/SMPTE_424M


So I guess I'm back to my orginal question which is if any manufacture offers dual-link SDI or 3G-SDI on a camcorder (one piece unit) for 1080p @ 60fps capture?

Note: I guess you'd be generating some pretty big files at almost 3G/s second. Do you archive the big files to LTO-5 and use 16G/b Fiber Channel or 10GbE LANs to move the big files around?

Dual Link HD-SDI
 

Hi Douglas:
The reason for dual HD-SDI is to effectively transmit the 4:4:4 color space signal, which is 50 % greater than standard broadcast wavelengths.

Mark's Response:The reason for dual HD-SDI is to effectively transmit the 4:4:4 color space signal, which is 50 % greater than standard broadcast wavelengths.

Thanks for that bit of information, now it's all starting to makes more sense to me. So conversly when they're talking about the new SMPTE 424M standard supporting 1080p @ 60fps over a single SDI cable that would imply you'd be able to transfer video upto a 4:2:2 color space. Does that sound about right?

If not then now I guess I don't understand what the new SMPTE 424M standard is for :-)

Single Link, Dual Link, & 3G HD-SDI Interfaces
 

Hi Douglas:
3G HD-SDI is simply a 3 Gigabit wide Interface which will allow a 4:4:4 bandwidth video signal to pass through a *Single HD-SDI interface, instead of having to use two (2) HD-SDI sockets to deliver the wider bandwidth video signal. (This would save space and money on a SSDR box [Like Mine] if I ever finish it !). A 3G HD-SDI interface is backwards compatible with standard broadcast HD-SDI 4:2:2 bandwidth signal interface.

Hey Mark,

Here is where I got that info from:

http://www.extron.com/download/files...sdihdmi_ts.pdf

Basically if you scroll down a little once you navigate to the page you'll see under
Mapping Structure One is you get:

1920 x 1080 4:2:2 (Y’C’BC’R) / 10-bit 60, 60/1.001, 50 frame progressive

So I miss assumed that I could shoot 60fps @ 1080p. using the 3G path.

1080 p60
 

Hi Douglas:
You certainly could shoot 1080 p 60 over 3G in 4:4:4 12 bit color space precision, as long as your camera can output this rate. The Sony SRW9000 HDCAM DR camcorder does precisely thus.

Hi Douglas. Most Viper shots are done 1080p 23.98. Nearly every feature that I know of shot with Viper are shot with that format. It's rare indeed that I change out of this mode. I did do some slight overcrank on a recent music video though. Shot 29.97 and conformed to 23.98 in post. The shots looked beautiful.

Most Viper shots are done 1080p 23.98. Nearly every feature that I know of shot with Viper are shot with that format.

That makes very good sense. the viper camera outputs such high quality at 23.98fps it really is like a 35mm film replacement. And since the film look is almost always associated with that frame rate look it's only natural that you would shoot at that frame rate.

You certainly could shoot 1080 p 60 over 3G in 4:4:4 12 bit color space precision, as long as your camera can output this rate. The Sony SRW9000 HDCAM DR camcorder does precisely thus.

Mark that really is good news! I noticed that the Sony HDC1500R444 does shoots 1080/59.94P. but I'm not sure if that's through dual-link SDI or through some other interface method. I tried to check out the Sony SRW9000 HDCAM DR, I ended up finding the SRW9000 HDCAM SR version instead. It supports dual-link for sure but not at 1080/59.94P. I think the answer is very soon new cameras will start emerging that do support this format on a regular basis. Probably when our compactFlash cards hold 512GB instead of 64GB :-)

Typo Model Error on My Part
 

Hi Douglas:
I hit the wrong key by accident describing the Sony model. There is only the Sony SRW 9000. This camera is an HDCAM SR camcorder. *It can do 1080 @ 59.94p via Dual LInk HD-SDI and I think 3G. (??) You need to have two (2) special hardware electronic optional boards inside the camera to accomplish this feature, however.

This camera is an HDCAM SR camcorder. *It can do 1080 @ 59.94p via Dual LInk HD-SDI and I think 3G. (??) You need to have two (2) special hardware electronic optional boards inside the camera to accomplish this feature, however.

Thanks Mark,

Now I know the exact Sony model number and camcorder that will provide this special type capability. I guess that's the end of this question :-)

what do you know about Adobe After Effects (Just kidding)!

The grassvalley LDK-8000 Elite using fiber and the LDK4582 fiber basestation outputs SMPTE 425M-A (3G) HD-SDI at 1080p50/59.94

Thanks Sander. Now I have a couple of options. There are some very esoteric ones out there like Viper Stream Camera Thompson but these are all very expensive and way over kill.

The ideal unit would coast under $50K and provide the basic broadcast capable quality using 2/3" chips and good low light levels f11 @ 2000lux. It would also support 1080p & 720p @ 60fps through dual-link SDI or 3G-SDI connection. recording to Solid state media would be good to. I guess you'd need to have about five (5) 64GB compact flash cards in it at a time :-)

Well the Thomson Viper Filmstream is no longer made anymore. It's definitely more than $50k so it's really not an option.

The LDK 8000 Elite however, is still current as far as I know. Of course the Sony SRW is a new camera and is also current. I don't think the Sony qualifies as an "under $50k" camera either, even before you start loading it up with option boards.

I checked I can get the Sony for around $75K and I'm still waiting for pricing on the LDK 8000 from Thomson but I'm sure that's up there to. The next generation will come down below the $50k barrier. I think some of the consumer ones already shoot at 1080p @60fps but they're junk basically.

This is precisely why I bought a used Viper. I looked at how much money I had then looked at EVERY option available for that much money. The Viper, hands down crushed every camera system on the planet for that much money. You find them for $25k these days. There is even a guy on this forum who had a chance to buy a Viper for $10k. Trust me when I tell you, there is nothing out there at $10k that can approach what a Viper is capable of.