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

[Peter Maersk-Moller <peter@maersk-moller.net>]

Hi

Christian Schuld wrote:
> Hi,
> On Tuesday 07 January 2003 11:03, Peter Maersk-Moller wrote:
> > Apparently on Eutelsat W3 at 7.0E on transponder C3 11262MHz
> > horizontal they are broadcasting in MPEG-4 rather than MPEG-2.
> > Has anyone been able to receive a stream (with the linux DVB
> > driver) and done something useful with it ?
> It is a TCP/IP encapsulated stream. Here is the log of a quick test, please 
> interpret yourself:
> pii:/home/chris/Downloads/dvbtune # ./dvbtune -n 2001
> Successfully opened network device, please configure the dvb interface
> pii:/home/chris/Downloads/dvbtune # ifconfig dvb0_0 up
> pii:/home/chris/Downloads/dvbtune # tcpdump -n -i dvb0_0
> tcpdump: WARNING: dvb0_0: no IPv4 address assigned
> tcpdump: listening on dvb0_0
> 11:40:09.167710 192.168.135.39 > 224.3.0.33: (frag 54185:1480@1480+)
> 11:40:09.168894 192.168.135.39 > 224.3.0.33: (frag 54185:1480@2960+)
> 11:40:09.169921 192.168.135.39 > 224.3.0.33: (frag 54185:1307@4440)
> [...]
Ok, so we have a multicasted stream. Probably an RTP based stream.
Players like mp4player and Quicktime should be able to play it if
we had the SDP file or means for generating it. It would be interesting
to see if any SDP announcements are made on the interface as well.

Does anyone know how to get the SDP info for these channels ?

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).

> > In principle, a budget card should be able to take the transponder feed
> > as a whole, but if the driver (or is it the firmware ?) adds a
> > MPEG-2 TS header to what it can identify as MPEG-2, it might not be
> > very useful data coming out.
> As you can see you can have the driver do the network stuff and grab stream 
> from 224.3.0.33 to process it further.
Interesting. If we can get the SDP info, and reconstruct a correct SDP
file including the MPEG4-IOD, then you can probably watch it directly
on a PC in high quality with common players. Writing a userspace V4L
would be trivial and maybe uninteresting.

--PMM



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