Wearable Computer System for HD Capture

[Chris Barcellos]

Kevin:

What about latency issues ? Can you use the touch screen as the monitor, or is there a lag ?

[Kevin Kondra]

Hi Jose,

I checked out some of the huge thread discussing your project with the Micron sensor and had the following thoughts:

1. The USB interface has a maximum throughput of 60MB/s, and if you want to capture 12bit/4:4:4 1080/24p video that creates a data stream of around 220 MB/s. That is a major limitation and the reason why HDMI and HD-SDI have been created to handle video data rates. If you are capturing video from your system at that resolution and color space, then the video stream is compressed and sent over the USB connection. Even 8bit/4:2:2 1080/24p would come it at around 100MB/s.

2. Speed limitations of serial connections will be the problem for all DIY image sensor projects. Working with and creating imaging hardware is not a DIY task, but connecting existing hardware, lenses, and data transfer connections is. An image sensor developer kit would need 10 GB ethernet to properly transfer HD data to a computer, which can be handled through a PCI express bus and compressed and recorded in real-time. A high-speed processor and RAID array would be needed to handle the video data, but is possible with today's hardware. Good luck making something like this portable in the near future without a huge budget.

3. Using SLR camera lenses is wonderful, it frustrates me so much to see camera manufacturers force us to buy high-end prosumer video cameras in order to get the optics quality found on $700 still cameras.

So the only thing I can suggest for your project is that a portable computer setup (like mine) to record video is not needed, since you have your data stream on the USB bus, just use a cheap laptop with fast hard drive. The portable computer I made cost more than $2000. My idea was to show the ability to capture HD video to a portable computer, from an HDMI source, or with a better camera over an HD-SDI connection. I am totally willing to help you out with any questions though, feel free to ask.

[Kevin Kondra]

Hi Chris,

There is no latency with the touchscreen, absolutely none. It works just the same as any computer monitor and is connected to the VGA connector on the motherboard.

[Serge Victorovich]

Hello, Kevin!
Do you tried to capture with use Cineform NeoHD or NeoHDV ?

[Kevin Kondra]

Hi Serge,
I haven't tried any of the Cineform products at all. So far I'm using the MJPEG codec from Blackmagic. NeoHD is pretty expensive so I'm not buying it quite yet.

[Serge Victorovich]

You can try NeoHD trial for 15 days and compare with BM JPEG.
Cineform codec is a really piece of Art.

I'm very interested in cpu (c2d T7200. right?) usage on the board like this AOPEN i945GTt-VFA with FSB667.
You can ingest full raster 1920x1080p24 use BM JPEG without dropped frames?

Kevin, keep this tread alive, please do more tests ! ;)

[Richard Leadbetter]

Kevin,

I echo Serge when he says you should move to CineForm HD - with the material I use it's a night and day difference. Put simply CineForm is as close to uncompressed as you'll get but with extremely low bitrates. I only use Huffyuv for 24-bit RGB work now - CineForm is king for 8-bit YCrCb, no doubt about it.

That said, CineForm absolutely flies with a desktop Core 2 chip so I'm wondering if there's an equivalent Mini-ITX board using socket 775? Or an announced board for Santa Rosa?

I've got to salute your ingenuity here - running XP from a USB flash drive in particular is genius. I'd like to build my own unit, and possibly mount the Xenarc monitor into the case. Any chance of a more detailed parts list?

[Michael Maier]

Nice project. How's the image quality? Is all the extra cost, bulk and work really worth it over the HDV tape? Any clips or comparison frame grabs?

[Steve Royer]

Did I miss something, or why hasn't anyone asked about the computer overheating in a backpack? How would any PC get the right amount of air into its fans?

I love this idea, but it seems cumbersome. I think you've done a great job gathering the right equipment, and I'm sure you'll figure out the optimal way to carry it all with future adjustments. Thanks for posting!

[Dale Backus]

Wow, very good idea Kevin.

I thought about doing this with a laptop or something and mounting that to the body somehow using the PCIe to Expresscard slot adapter... but that would be a little too sketchy...

What case are you using for that? It looks smaller than anything i've seen recently.

Any idea as to how long the batteries will last running this rig?

Great execution though - it's very impressive.

It really astonishes me though, how there's this HUGE need for HDMI direct-to-disk recording, but it's just like the developers are asleep or something. How hard would it be for Canon to make something like this? Or Blackmagic even?

Is anyone listening? A fortune is at hand for anyone who can come up with a cheap box with HDMI recording with a decent codec. The only thing i've seen is at www.colorspaceinc.com. IT looks very intriguing, but no mention of cost is made. It could easily be a 10k piece of hardware, but hopefully not.

Sorry to veer off... great job Kevin!

[Serge Victorovich]

Steve, the bag can had mesh on the sides for ventilation.
With small (sub)mini-ITX motherboard as Gene-9310 possible to create a dvr-on-the-belt or device similar to Codex Portable in size as mac mini.

[Dale Backus]

Just ran across something...

I was spec'ing out my own rig similar to this, and looked at batteries pretty in-depth.

The battery you're using Kevin is a pretty good one, but i found one for a tad cheaper on Ebay. You're paying (if you got yours for 80 bucks like i saw it) about $1.33 per Watt Hour. I found some on Ebay that came in at around $1 per watt hour.

http://cgi.ebay.com/8-10-hours-Dark-...ayphotohosting

There's the link if you're interested...

Correct me if i'm wrong, but that the AOpen Mini-ITX states it's 19VDC at 4.7 Amps - so that should be just under 100 Watts. If you got a battery that states it's 133 wH, that should last about 80 minutes or so right?

[Chris Ames]

Originally Posted by Richard Leadbetter

running XP from a USB flash drive in particular is genius.

Here is a fairly significant problem. If your entire OS is running on the flash drive, including the page file, the flash drive will have a short life. I've read maybe 3-6 months. And when it dies, it won't go nicely.

Not the end of the world as flash memory is cheap these days. I'd be more concerned about the unpredictable moment of death. May want to keep a spare loaded up with XP ready-to-go in your bag as a backup.

Chris

[Dale Backus]

That's an interesting tidbit of info...

Where did you hear that? I read that they're going to be integrating Flash Disks (up to 512 Gig has been announced) more and more into consumer products such as small form factor laptops and things. Wouldn't this be the same? They estimate in a couple years that flash memory will occupy about 30% of the storage market - if this is a problem, they better figure it out soon....

I was thinking of getting one of those samsung 32 Gig flash drives and install it in the computer, then record using Cineform which is about 10mb/sec? You'd have like 45 minutes of record time, then during a break or a set up or something, you could dump it to a external RAID-1 hard drive for backup and storage, and repeat...

This way you wouldn't have to worry about jarring the computer during capture (these flash disk are rated for like a million G's) and you wouldn't have to carry around another component. It would be better on battery life as well.

Just a thought...

[Dale Backus]

http://www.storagesearch.com/bitmicro-art3.html

Interesting article on the topic... if you have time

http://www.storagesearch.com/ssdmyths-endurance.html

This in particular