The only cable you'll ever need?

[andrewducker]

This Register story talks about a webcam using USB3 to stream 1080p HDTV in real time.

I hadn't realised that the bandwidth was quite that high - but looking at the specs, USB3 can manage 4.8Gbit - which is high enough to carry 1080p video without a problem (uncompressed RGB being 2.5Gbit) even with transimission overhead.

There doesn't seem to be a device class for video players (There's a video class for video producers (webcams and the like), but there's no reason why one couldn't be produced.

I suspect that there would be "security" implications over using it for things currently encrypted over HDMI - but I don't know enough about the details.  In any case there doesn't seem to be a technical reason why your graphics output couldn't just be another USB socket...

Comments

[the-magician.livejournal.com]

My second monitor at home is on a USB2 socket, so no reason at all!
http://www.displaylink.com/technology_overview.html

I assume when you say "security" you mean "DRM".

I'm looking forward to USB3.0 external hard disks, or even just a USB3.0 link to the 7-port USB2.0 hub so that each of the drives on there can have the full 480Mbps up/down to the PC for copying data from one drive to another.

[andrewducker]

Ooh - didn't know about that. I've got an HP laptop - and they produce a docking station that uses that technology. Once I get my desk set up in the flat I'll be looking into that...

[the-magician.livejournal.com]

http://www.hp-laptop-batteries.net/us-multi-display-adapter.htm

I think I've seen them under $50 ...

... I use an LCD 19" monitor with my HP laptop to give me two screens (same with my work Dell I'm typing this one) ... and my Dell desktop at home has the USB->VGA monitor adapter from DisplayLink to give me two 19" monitors on there.

HP part number NL571AA
e.g. http://www.provantage.com/hewlett-packard-hp-nl571aa~7HEWA150.htm

Add up to six adapters to have up to six extra screens on your HP laptop!

[andrewducker]

Oooh cool. Any noticable slowness/judder from using it? And does it get any slower with multiple monitors?

[the-magician.livejournal.com]

I'm not using the latest HP unit, but a demo unit produced for/by another manufacturer in about 2006 ... one of my LJ friends works for DisplayLink and got me an old prototype to play with!

No particular delay, it's not really suitable for playing fast games on, but it's fine for watching DVDs/AVIs. At least one video playing thing (and it may have been YouTube) had problems if the active video was overlapping between the two screens, one half went black ... but it works fine if the entire video clip is on one screen ... and that may be a problem with the age of my particular unit rather than an inherant problem...

... I've not tried multiple screens (beyond one USB extra).

I'm guessing it works by having your graphics card render out a bigger desktop, then having a video driver that takes the bitmap of the part on monitor 2 (3,4,5,6) compressing it and sending that compressed bitmap out to the USB connected unit that converts it back into a VGA/DVI signal. Mine does 1280x1024 which matches the resolution of my 19" monitor perfectly. I don't know if it only sends the differences between frames, or if it compresses the entire frame each time. 1280x1024 is about 1.3Mp and with 32bit colour that's about 5Mbps, and USB2 can handle up to 480Mbps ... if there's compression (and I'd guess at least RLE) then it's probably under 1% of the USB bandwidth per screen. The CPU usage seems to be quite low at the PC end.

[andrewducker]

It was CPU usage I was curious about. If that really is low then I'll definitely be picking up a unit when I get my desk set back up again!