[linux-dvb] Re: DVB and MPEG-4

[Alexandre CONRAD <aconrad.tlv@magic.fr>]

> How did you get them ? Can you share them ?

I got them with the open-sky client. Open-sky listener. Don't you have 
it ? If you do, it should be in Open-Sky/content/Eutelsat/LiveTV

> > The ASX file has all the infos about the clip. The NSC file has all 
> > the streaming / broadcasting info.
>
> So a proprietary non standard solution.
Yes. But I guess you can look inside these files to see what IP's it 
links to.

> > You should be able to read these files with Windows Media Server (I 
> > think). At least, the program that have generated them. But after 
> > talking with Eutelsat, I pretty much know how this works. And they 
> > are using Windows Media Server.
>
> So a proprietary non standard closed insecure solution subject change
> to without further notice :(
>
> One should think Eutelsat was wiser.
>
> Hell, it might not even be MPEG-4 but rather MS-MPEG-4 :( 
To do that, they get the TV stream into a Pinnacle server factory (some 
expensive rack machine)

http://www.pinnaclesys.com/ProductPage.asp?Product_ID=100

So the stream get's into that, it's encoded into MPEG4 (maybe standard 
MPEG4). They have a Stream factory server for each channel. Each factory 
servers is then connecter to a Windows Media server node that manages 
the channel and broadcast them over IP. So they generate these ASX and 
NSC files, and put them in the open-sky client. So when you open with 
windows media player, WMP knows the format, and get's the stream from 
the PID. It works pretty well... But I have only tried that under windows.

> > > BTW, it is a dangerously channel to tune into. It means that it will
> > > typically be sending a full feed (45Mbps) of multicasting traffic
> > > towards you and your PC will quite often forward this traffic to
> > > your default route (or your multicast route). 
> > These MPEG4 channels are only 450kb/s. But maybe I don't know enought 
> > about satellite to argu on that. :)
>
> I thought they were broadcasting in better quality. Anyway, 19x450kbps
> is approx 8.5Mbps. That's usually much more than needed to saturate a
> home network (10BaseT or 802.11b). What is worse is that it can work
> as a fine denial of service attack on your home router since such a beast
> usually can't handle high load of multicasted traffic. After all these
> router (or CPEs) only have a slow embedded processor to handle it all. 
Well, I can't tell, when I have read these channels under windows media 
player, it didn't seem to saturate. It only buffers 1 channel of course. 
I don't know how much data the card really gets.

> So disabling IP-forwarding or using a filter on your PC receiving
> multicasted traffic from satellite is advisable. 
Regards,
--
Alexandre CONRAD
Research & Development
tel : +33 1 30 80 55 00
fax : +33 1 30 56 50 20
TLV
6, rue de la plaine
78860 - SAINT NOM LA BRETECHE
FRANCE





--
Info:
To unsubscribe send a mail to listar@linuxtv.org with "unsubscribe linux-dvb" as subject.