[linux-dvb] UDP encapsulated MPEG{2,4} TS into dvbsnoop?

Alexander E. Patrakov patrakov at ums.usu.ru
Thu Oct 11 14:57:21 CEST 2007


Walsh Rod (Nokia-NRC/Tampere) wrote:
> If you're on the West side of Russia you might be getting something DVB-H
> from the East of Finland over DVB-T: but I very much doubt it.

Yekaterinburg => way too far, and the antenna company wouldn't sell 
receivers if this is not a local broadcast.

>  In Finland
> most of the DVB-H trials are in the West and they'll be increasingly headed
> for their own Mux and 4k mode (DVB-T receivers ought to only be capable of
> 2k and 8k, unless yours is seriously over specified.)
>   

This broadcast can be tuned to by running dvbtune -f 626000000 -bw 8 -gi 
8 -tm 8 -m

> Does the LinuxTV API still have the MPE/IP APIs functioning?

Where can I read documentation about this API?

> If so, that
> should be enough to get the IP packets off the air.

For me, running "dvbnet" with appropriate parameters was enough to get 
valid UDP packets (but with unknown meaning of the payload) from the 
dvb0_0 interface.

> Though if it's indeed a
> 2k DVB-H you'd find encryption in either IPsec or SRTP fashion.

I don't know what IPsec or SRTP packets look like in a tcpdump file, but 
at least UDP headers are not encrypted, and the first 4 data bytes look 
like some big-endian counter that gets incremented by 1 after each 
packet (separately for packets sent to ports 20000 and 20002). The next 
4 bytes also look like a big-endian 32-bit number that increases for 
each packet by approximately 1920 for port 20002 and by 3600 for port 
20000 (that has less packets sent to it) - looks like a timestamp.

> I have no
> idea what open source tools might be available to call the MPE/IP APIs for
> you though.
>   

I know C enough to write a simple program that calls it, given the 
documentation.

> On 10/11/07 1:06 PM, "ext Alexander E. Patrakov" <patrakov at ums.usu.ru>
> wrote:
>   
>> Here is a packet dump (1300 KB): http://ums.usu.ru/~patrakov/udp.dump
>>     

-- 
Alexander E. Patrakov



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