[streaming] Re: (no subject)

[psaade.vlc]

Dave Schroeder wrote:

> We are currently distributing 12 TV channels using MPEG-4 (Part 2) on 
> a 100mbit multicast network, but we are using QuickTime to do the 
> encoding and delivery (though we support VLC for playback). We are in 
> the process of expanding to 77 channels that will also delivered via 
> multicast, and will be moving to H.264. We also distribute optional 
> closed captioning for each channel. We used QuickTime because we 
> wanted to distribute the video in open formats (e.g., MPEG-4, AAC) and 
> open protocols, but also wanted a product supported by a commercial 
> vendor.
>
> It is doubtful that there is any equipment you would be able to use 
> that would not require you to buy some kind of a tuner for each 
> channel. Also, if you're planning on doing a high quality broadcast, 
> you shouldn't plan on being able to do more than two channels per 
> server if you are encoding in software. If you are doing hardware 
> encoding, you can do more, but I'm not familiar with any equipment 
> that would allow you to do multiple channels (other than simply 
> getting multiple TV tuner cards and multiple servers to hold them).
>
> In order for this to work for you, ALL of your clients will need to 
> have multicast connectivity between themselves and the video 
> server(s). But, from a network standpoint, yes, it is definitely 
> possible...but only you know the datarate you plan to encode at. If 
> you are doing 25 channels at, say, 1 Mbps each, and they will all be 
> used all the time, that's 25 Mbps of used bandwidth plus some 
> overhead. A properly configured switched 100mbit network will handle 
> it, but you need to keep in mind your limitations. For example, we 
> don't have all channels in use at all times, but in our case, all of 
> our 100mbit clients across campus, which number over ten thousand, are 
> connected via 1Gbit, and in turn a 10Gbit backbone, so even 77 channel 
> delivery across the whole campus is not a concern.
>
> For more information about our installation, see:
>
> http://datn.wisc.edu/about/
>
> Regards,
>
> Dave Schroeder                 |    University of Wisconsin - Madison
> Email: das at doit.wisc.edu       |   Division of Information Technology
> Pager: das-pager at doit.wisc.edu | B263 Computer Science and Statistics
> Pager: +1 800 449-4951         |              1210 West Dayton Street
> Phone: +1 608 265-4737         |        Madison, Wisconsin 53706-1685
>
> On Feb 27, 2005, at 11:22 AM, Ugo Angelini wrote:

Do you have any experience on such things based on Linux servers ? I'm 
looking for a brand or model of video cards, well supported under Linux, 
and that would allow me to do software encoding and streaming from a Y/C 
(S-VHS) input.

Thank you for any information. And thanks for the link you gave. 
Interesting.

Best regards.

P Saadé
Maths Teacher La Martinière Monplaisir
Lyon, FRANCE
http://psaade.free.fr

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