Sending Live Television Via iChat

I thought the following was well known and therefore something no-one ever bothered mentioning, however recently I've been told it isn't that obvious at all, so I thought it would be worth writing it up for everyone (including Mr Dolan and Mr Coates, if that's OK) to enjoy....

The recent versions of iChat have, of course, brought with them the capability to use a video source (for most people, that would mean an iSight, or a USB webcam using a hack to get it to work in iChat - see my old post about that, or even perhaps a firewire-output home video camera they already own) for video chatting/conferencing. However, if you just so happen to be someone that has purchased an analogue video -> DV (firewire) converter box in the past, such as the Formac Studio, you might be suprised to learn that when it's plugged in it is presented to the Mac (and specifically the iChat application) as a perfectly valid firewire input device. In other, shorter, easier, words: you can use your converter box to stream live video from something - oooh, let's just say your Sky Digibox for example - to someone else using iChat anywhere else in the world. If you happened to have one of the outputs of your Sky box (it has two) connected up to the inputs of your converter box, you might see how this could work.

Free TV! Well, kind of....

Firstly, not ALL analogue->DV boxes seem to work for this, I think it depends on the type of hardware (specifically the chipset used to do the actual digital encoding) you have access to. My box seems to contain a Panasonic chipset, which the Mac OS is perfectly happy to communicate with.

Bandwidth: as with any video over IP situation this is an issue, and as most of us in the UK still have to battle with asyncronous broadband (aka, you can't send data as quickly as you can receive it) you have to limit the bandwidth (and so the quality) of the video pictures you're sending to another. Don't expect full screen smooth video using this setup, the other person is likely to get a small, but usable, window size worth of moving video that can be a bit jerky at times; but it's perfectly watchable if you just sit the window in the corner of the screen and don't concentrate on it too hard :)

If you're sending video one way using this system (perhaps, say, to your other half who - despite simply supporting the wrong football team - would like to watch their last game of the season but cannot get Sky TV where she happens to be right now) you'll likely to be using the "One-Way Video Chat" function in iChat - the warning here is that you can then HEAR THEM at their keyboard typing away (or eating crisps even) - if they have a microphone setup or in their ibook/powerbook of course - but they can't hear you (as they'll hopefully be listening to the audio that goes along with the video you're streaming to them). It's something to remember, and mention to them...one sided audio chats are weird.

There's an issue, sometimes, with the audio staying (actually, not 'staying', I mean 'ever being') in perfect sync with the video, but I do think that's problem with my particular setup, and am working on how to fix that and will explain the solution here if possible.

Important note: This is only likely to work with boxes that don't need software running on your Mac to control them (or decode the data they are sending, to be more accurate), or at least boxes that have the option not to use software (my box just does conversion all in hardware with no software needed). Why? Well, I tried this with an Eye TV 400 Freeview-type box (which is very good by the way) but, because it doesn't squirt 'raw DV' into the firewire port, it needs the supplied EyeTV software running on your Mac - at all times - to turn the data sent by the hardware box into watchable pictures. And - you can see where this is going I bet - you can't access the data from your hardware box in iChat as it throws up a "your video camera is being used by another application" error, which is kind of true enough, I guess!

Of course, it's probably not legal as such to rebroadcast someone else's TV output over IP like this, hence that's why I'm not saying I've actually ever done this at all. Oh no. It's all just a theory. Honest.

*cough*

Addendum:

Apparently, the lastest update of iChat now works well, video-wise, with the latest version (5.5) of AIM for Windows which means that this little trick might well be useful if you want to send a TV-type video stream live to a PC-owning friend as well as the better-informed, more attractive, more fun-loving Mac-owning people in your life.

Posted By Simon Thornton @ 4:39:56 PM  trackback []  comment(s) []