How can one send a live video signal within a local area network?
March 15, 2007 8:11 AM   Subscribe

How can I send a live video signal from a digital video camera to a remote computer (Mac) within the same LAN?

We have a fast network and it would seem possible to get a signal from a video camera, feed it directly to a mac, then send that signal out over the LAN to another machine for local rebroadcast on a TV.

How would one do this? Could it be done without special software or hardware?
posted by kingfisher, his musclebound cat to Computers & Internet (8 answers total) 1 user marked this as a favorite
You can probably do it with iChat, assuming the camera's a DV camera that's recognized by iChat (or a USB Webcam with iChatUSBCam).

There's even an iChat pref which can be used to get it to auto-accept incoming video chat requests. In Terminal, do this:

defaults write AutoAcceptVCInvitations 1

iChat does support one-way video chats so I don't think both machines will need a cam.
posted by kindall at 8:20 AM on March 15, 2007

It's incredibly easy and free to set up a "unicast" video feed with QuickTime Broadcaster.

In broad strokes:

• You connect your DV camera to the Mac running Broadcaster
• Set up a unicast feed (read the built-in Help, it's just a couple clicks)
• Email or copy the unicast link to the other Mac and open it with QuickTime Player
posted by Blazecock Pileon at 8:21 AM on March 15, 2007

As a tag-on (hope that's cool):

is .Mac really the only sure-fire way to get iChat's AV going between two iSight enabled Macs? I've heard AIM can do it but I'd much rather use Jabber.
posted by dance at 8:33 AM on March 15, 2007

You can use iChat via Bonjour on a LAN, or OS X Server to run a Jabber server with Open Directory accounts.
posted by Blazecock Pileon at 8:36 AM on March 15, 2007

Yeah, on a LAN just use the Bonjour mode.
posted by kindall at 8:40 AM on March 15, 2007

Response by poster: Thanks for the suggestions. These will all compress the video -- maybe that is necessary and will be what we do. But if we are local, is there a way to send uncompressed video that would be good for a TV (maybe 36")?
Wouldn't the compressed video have a lot of artifacts?
posted by kingfisher, his musclebound cat at 9:25 AM on March 15, 2007

Best answer: Remember that a TV has the rough equivalent resolution of 544 × 372. With the bandwidth your LAN allows, you can send a high-resolution (e.g. 640 x 480), high-bitrate compressed video feed and it's unlikely you'll notice artifacts.
posted by Blazecock Pileon at 9:32 AM on March 15, 2007 [1 favorite]

Best answer: I'm not 100% sure of this, but I think that Quicktime Broadcaster will let you change the encoding/compression settings, and might let you send the raw DV stream across the network. iChat won't.

[That's not "uncompressed" video though -- DV footage is already compressed (it's an intraframe codec, like MJPEG, as opposed to a interframe predictive codec like MPEG-2 or -4) -- but it might be what you're looking for.]

I'm not sure how hard that's going to be on your network, though. A DV stream is 25Mbit/s if memory serves, plus you're going to have a lot of overhead for the stream. Unless your network is totally unloaded, I suspect you're going to want GigE.
posted by Kadin2048 at 10:27 AM on March 15, 2007 [1 favorite]

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