[AG-TECH] Voyager server

Markus Buchhorn Markus.Buchhorn at anu.edu.au
Mon Feb 23 23:53:38 CST 2004


At 11:30 23/02/2004 -0600, Michael Miller wrote:

>I'm wondering what the storage needs are for a voyager server.  I think I remember someone telling me about 1MB/minute/video stream.  Does this sound right? 

If a typical h.261 video stream is around 500kb/s on average (which depends a lot on what it is pointed at, and what the cap is set to), that converts to around 3.5MB/minute. However, it really does depend on what is being sent (unless you are using a fixed bandwidth codec, like mpeg or mjpeg or dv), and so the actual rate can vary from 40kb/s to 800kb/s (presuming an 800kb/s cap, and I have seen vic go over the cap sometimes). So it's an integral of how much your audience is moving around :-)

> I know it often depends on the characteristics of the video streams in the session, so, let's assume for a moment we have two sites with 4 streams each, and each stream is using the 800Kps setting in vic and the audio is done with the typical codec used in AG sessions today.
>
>Anyone care to throw out a ball park figure?

800kb/s = 6MB/minute, times 2*4 streams = 48MB/minute. Audio is either 128kb/s or 256kb/s on the default codec (not a great choice, btw, you can do better, for less bandwidth), so add 256kb/s ~= 2MB/minute times 2. So you're up to 52MB/minute in this scenario, presuming everything is constant. 3GB an hour.

An experience I had was recording content for a bio-conference last year, of around 10 sites, 3-5 video per sites plus audio, for about 8 hours a day - that came to about 40GB per day. So I think the above estimate is overly pesimistic - people don't move around that much. 

Conversely, there are several people like us working on higher-bandwidth video ;-)

Cheers,
        Markus


Markus Buchhorn, ANU Internet Futures Group,       |Ph: +61 2 61258810
Markus.Buchhorn at anu.edu.au, mail: Bldg #108 CS&IT  |Fx: +61 2 61259805
Australian National University, Canberra 0200 Aust.|Mob: 0417 281429




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