FW: [Malvern] Video Networking

[Andy Morris]

Ian,

There is the added restriction of network efficiency and utilization. 
 From experience, a NetAdmin who found more than 30% continuous 
bandwidth use on a LAN would be panicking at the risk of data loss. It 
may say 100Mb, but actually getting it is another matter - because a LAN 
is "open-broadcast" not point-to-point. To do what you want to do would 
need a 1Gb LAN, at least, or change to a more efficient network type 
(such as ATM).

Andy


Ian Pascoe wrote:
> Chris / Rik
> 
> Thanks for your replies guys.
> 
> OK, so looking at a 10 base T network running at 10mb, to get a fully
> un-compressed data stream from a DVD file would totally engulf the network
> at one extreme, or looking at the average data rate still only allow one
> data stream to be viewed; ie average rate of 6-7 Mb would require a minimum
> bandwidth of 12Mb to view 2 data streams.  Or am I missing something
> fundemental in the way networks work?
> 
> Taking it to the next level of a 100 base T network with a bandwidth of
> 100Mb this would give the potential of about 15 data simultaneous streams
> with a bit of bandwidth left over.  In this case if everything was sourced
> from one server and one HD would you then run into problems with the amount
> of data that could be read off the HD to provide these data streams.  I know
> that for instance you could get around this by dumping the file into memory
> and streaming it from there but keeping it simple with the assumption that
> what comes off of the HD goes straight out into the network.
> 
> Sorry about keeping on with this but it niggles!
> 
> Ian
> 
> -----Original Message-----
> From: malvern-bounces at mailman.lug.org.uk
> [mailto:malvern-bounces at mailman.lug.org.uk]On Behalf Of Chris Eilbeck
> Sent: 17 March 2006 23:46
> To: malvern at mailman.lug.org.uk
> Subject: Re: [Malvern] Video Networking
> 
> 
> On Fri, Mar 17, 2006 at 09:33:37PM -0000, Ian Pascoe wrote:
>> Evening all
>>
>> Following on from the conversations at Geoff's on Wednesday - apple cake
> and
>> quiche very much up to standard thanks Geoff.
>>
>> A question for those of you involved with networks.
>>
>> If you have a LAN with a server and a number of PCs off of it, what is the
>> limitation to how many people could view the same video source if stored
> on
>> the servers HD?  Would this be limited by the server's hardware, network
>> bandwidth or something completely different.  The source would be fall
> blown
>> DVD material.
> 
> You'd have trouble doing this over most cheap networking technologies.
> You'd definitely have to have a switch rather than a hub.
> 
>> I presume that within any network the Tx and Rx have a small buffer on the
>> network cards that once filled is downloaded into the PC?
> 
> Yep.
> 
>> Does anyone know what the transfer rate is for data coming off of a DVD
> data
>> file?  ie CD Audio is something like 128k/bps.
> 
> CD audio is 1.5mbps.  DVD video can be upto 10mbps but is usually around
> 6-7mbps.
> 
>> Why am I asking - for no other reason than would it work at home - ie you
>> load your DVD onto a HD and you can take your laptop / PC in which ever
> room
>> to watch your favorite film whilst someelse is doing the same in another
> and
>> so on.
> 
> That'd be cool.  Have a look at http://www.videolan.org/
> 
> Chris
> --
> Chris Eilbeck
> MARS Flight Crew                              http://www.mars.org.uk/
> UKRA #1108 Level 2                                                UYB
> Tripoli UK Member #9527                                          LSMR
> 
> _______________________________________________
> Malvern mailing list
> Malvern at mailman.lug.org.uk
> http://mailman.lug.org.uk/mailman/listinfo/malvern
> 
> 
> 
> _______________________________________________
> Malvern mailing list
> Malvern at mailman.lug.org.uk
> http://mailman.lug.org.uk/mailman/listinfo/malvern
> 
>