Portable HD-SDI - Reborn
 

Hello all,

I'd like to restart the thread that Brad had started a few month ago about a portable solution to record on the field the HD-SDI feed.
http://www.dvinfo.net/conf/showthrea...light=portable

Brad was saying "We agree that recording a fully uncompressed HD-SDI signal on something portable is not practical due to needing an array of some sort."

This was totally true... at that time... but Alienware just announced a laptop with internal high capacity dual hard drive in sata mode.

http://www.alienware.com/press_relea...ss01172006.asp

Yes you heard me, a laptop with two 160gig hard drives in raid 0 is now possible !!
Before we could have a portable external raid system to plug into the laptop but the speed was limited by the firewire or USB2 connection.

Hold on your excitment cause we still have a big issue... neither Decklink nor AJA offer a way to get an HD-SDI signal into a laptop.

I thought that a PCMCIA version of their HD cards would exist, but apparently not.

It might be because of PCMCIA limitations or because there was not simply any market.

Now that these dual hard drive laptops are out there who knows, maybe they'll see the opportunity to release a new product allowing us to access the Holy Grail: Acquiring in 4-4-4/10bit on the field....

So if anybody can bring us more info on an HD PCMCIA Card please do so.

Arno

PCMCIA dosn't have the bandwidth to handle HDSDI, 2 SATA drives if fully optimised might just do HDSDI, but if they are 2.5inch laptop drives they just won't do it.

You mean 4:2:2/8bit, that's the max.

Well yes of course if we're using the HD-SDI it will be 4:2:2 but if we use the analog output then those HD cards can acquire at 4:4:4 10 bit.

Now if the limitations of PCMCIA prevent them from transfering the data to the HD fast enough then it's pointless.

So again there is probably a reason these companies never though about making a PCMCIA version of their cards, and there is a good chance it's because of the interface limitations.

But as far as the hard drives you can find 2.5 ones speeding at 7200RPM and in SATA mode that are as good as the 3.5 used in professional SATA raid arrays.

In reality, no one can tell the difference between 2:1 and 1:1. Even
@ 4:1 HD will look great and have more pixels to work with than
DVCPro 100.

obvioulsy technology will have to catch up, and from a product/waste standpoint, replacing desktops with labtops is gonna happen. Much has to do with the cooling technology with processors in cramped spaces, and the physical size of the hard drives. IBM (if I remember correctly) is presently releasing a new form factor that uses a stacking technology vs. the spinning disk/platen, that will greatly improve the capacity of labtop memory.

I also think the way manufactures view labtop design shall change from that of a busy sales and email tool, to an actual desktop replacement. It's the logical order of things, and we can help it along by voting to spend our dollars if and when these devices are made available.

In the meantime, I'm thinking about a shoebox sized case, the smallest 'desktop' form factor at present. Something similiar to Newtek's tricastor, which houses a full sized VT card. Something of that size could be custom mounted to a heavy duty tripod for semi-portability.

Presently I have full size Dell 650 workstation with a VT/switcher and mixer all mounted to custom build cart that easily fits onto a dolly or handtruck. Still it's a pain and workstations are not built to be moved around. So, a shoeboxed size form factor is a welcomed compromise.

2 Hard drives, really good 3.5" sata drives might sustain uncompressed HD-SDI for a minute, but the only speed that actually ever matters for a hard drive and video capture is the minimum sustained trasfer rate. 2.5" drives bottom out even the fastest around 30 mbytes/s (and more around 20 mb/s) while the fastest 3.5" sata I've seen is just above 50mb/s (this is the minimum fo the raptop 74gb version which does 74 mb/s is at the fastest). So no matter what you do your going to need a minmum of three hard drives for uncompressed and a bus that is faster than PCI. Your going to need 150MB/s incoming and even if you compress 5:1 your going to need another 30 outgoing.

In several years when pci-e architecture with some form of card slots hit the laptop market this will be do-able but being able to push around that much data fast enough is not within portable computer hardware that I've seen. However SD-SDI can be done with a laptop via Kona's IO device and firewire.

I'm likely a little biased since a solution to this problem is my actual job, I'm just going about it differently. From my research its apparent that compression is going to skyrocket power consuption with a portable computer so you might get an 1 - 1.5 hrs on a 90whr laptop battery under compression so unless a dedicated encoding IC is used it starts to become less portable.

I'd love to listen to some of peoples thoughts on a portable unit though. It's peoples requests that have guided my work thus far.

Keith, your HDU-1 project is very interesting. Obviously that would be a much better solution than a laptop considering the power supply needs.
You're saying theHDU-1 is using 30w an hour, that seems really low considering that you'll have an array of 10 HDs in there but maybe I did not get it right and that it's without the power consumption of the raid array.
Can you tell us more on this?

I thought about the issue even with the laptop solution and the only somehow "practical" way would be to have a car battery on the set with an inverter to plug the computer everytime we are not shooting and keep the battery always charged more than 50%. We always carry one on our guerilla shoots or have one in the car (as a matter of fact) so that would not be too much of a new situation.

Now an advantage of the laptop or "shoebox" PC would be that we could use new codecs as they come.
I was not thinking with the laptop to actually record uncompressed but to be able to choose the most up efficient option without being stucked to one proprietary one. Let's say now the Avid DNxHD would seem a good option right now.

Because if we were to use the HDU-1 on the field even on indie film a lot of people will find the 800Gig or even a 1TG option rather limitating.

Of course you could say that we have the option to dump the footage to an external set of hard drives during a break or set up change. But here we get back to a similar situation than the P2 case, except that it's not a few gigs that we have to dump out but close to one terabyte!!! Much less affordable and practical for indie guys!

I think you mentioned in your pdf codec recording being possible. Can you tell us more about this as well?

Thanks for developping such devices, we definitely need these, the cameras are at reach, the 35mm adpater as well, we just need the final element!!
Well... not exactly, we still need an amazing story or documentary subject to shoot otherwise all this is just looking at the finger pointing to the moon...
(We all know this but it's just good to state it again sometimes)

Arno

Keith, The HDU-1 project seems highly interesing. I'm myself after something like the Wafian device --i.e. the signal from the HD-SDI is compressed with Cineform or equiv. codec and stored on a HD-- but as a portable unit. The specified size of the HDU-1 is in my eyes in the class of portable devices, and the remaining issue is, what kind of battery is needed to run the HDU-1 for several hours.

Since I work outdoors, I would not call a laptop portable. For, it takes awfully lot of power, and you can use it outdoors only if it is a birght warm day and there is no dust, sand, or whatever dirt around. In this sense the HDU-1 specs suggest a completely different kind of portable device.

For wildlife videography --in my view-- one needed a portable device which can store about 5-10 hours of compressed video without a need to change the battery, or alternatively, one is able to use the XL H1 batteries. Those who work with wildlife videography need to archive the material, so compression is almost a necessity. (Cineform compression should be just fine.) If there is more capacity, the weight of the device may become a problem.