[mythtv] DVB patch for Freeview/Xtraview

Rob Jones robj at fastmail.fm
Tue Apr 12 11:44:28 UTC 2005

> The second more important issue is the legality. I have read a lot of
> postings 
> about this and as far as I can see it is legal. There is no encryption on
> the 
> channels. They are simply sent is a way which most boxes are unable to
> pick up 
> the reception (the streams pretend to be subtitles).
> All the Xtraview site says is:
> "XTRAVIEW uses proprietary Top Up TV technology. You must not attempt to 
> decompile, disassemble, modify or reverse engineer this technology."
> That's fine. I didn't.

I haven't had chance to try the patch yet, but, on the legal side it
does raise an interesting question.

For anyone unfamiliar with "Xtraview", it is an attempt by a UK DVB-T
operator to broadcast pay tv, without the use of real conditional
access/encryption technology. Instead of encrypting their broadcast,
they remove all valid references to it in PMT table in the DVB stream,
and do not correctly label the PIDs as MPEG video and audio. Instead,
the viewer is redirected to a set of PIDs carrying no/invalid data, and
an interactive MHEG application is launched.

The application generates a serial number, and hashes it to create
another number, which the user finds out by dialing a premium rate
number. If he/she then enters the correct number, the interactive
application directs the receiver to the correct PIDs, and they can then

While effective for MOST set top boxes that do not allow manual PID
entry, anyone with a DVB-T PCI card, or even some set top boxes that do
allow manual PID entry, the system has a gaping hole in that all you
need to do is be told of the PID numbers or analyse the transport stream
yourself to find out what the numbers are.

So then, is this decompiling, disassembling, modifying or reverse
engineering this technology? I don't think so, as you are at no point
reverse engineering their key generation algorithms etc., you're just
manually tuning in a channel, which circumvents their application, but
doesn't actually 'hack' the service as such.

Their is the legal argument of intent though; as by doing this you are
still technically stealing the service, regardless of the technical
arguments of how you did though.

As far as MythTV is concerned though, all this patch does is allow Myth
to manually decode video streams on xtraviews pids. I guess its the same
argument as for BitTorrent et al., they don't break any laws; it may
allow you to do so, but manually entering the PID values is still valid
way of receiving any other broadcasts legally or otherwise; it doesn't
break the law in itself. But writing a patch to Specifically get around
this one scenario.... seems like a grey area!

Just my 2p's worth....


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