[mythtvnz] DVB-T MHEG EPG

[Steve Hodge]

On Sat, Apr 17, 2010 at 9:25 PM, Tortise <tortise at paradise.net.nz> wrote:

> From: "Aaron Whitehouse" <lists at whitehouse.org.nz>
>
> What sort of application is it? Surely there will be a variety of
> > FreeviewHD-approved products out there and they will have to be able to
> > deal with updates.
>

> While I do not know I have been thinking along the same lines as Aaron, if
> they make any significant changes there is a heap of
> commercial kit that is going to fall over - and there are going to be a
> heap of upset users complaining about broken commercial
> boxes.   For example the over the air firmware updates are done in blocks
> of weeks so they are unlikely to happen overnight for all
> commercial users.
>

You're both assuming that the code to build the EPG is in the firmware of
the devices. My understanding is that that is not the case. The firmware
contains an MHEG parser that knows how to build an application from the MHEG
data found in the stream. It's a general purpose thing, basically like a
language runtime. The EPG is implemented as MHEG code delivered in the
broadcast stream and it is the EPG code that understands the guide data that
is also embedded in the stream. So Freeview could, at any time, simply
change the data format and update the EPG code that is in the MHEG stream.
No need for firmware updates at all.

So while they might be free to make changes, the chances of these happening
> very often are in my view remote.
>

I disagree. Since Firmware updates are not required I think changes are
extremely likely. Most likely changes will be driven by increasing
functionality but they could simply change things to make it harder to
extract the data. And if someone writes a tool to extract the EPG data and
the data then gets republished on a website they'd have a good reason to do
so.

Cheers,
Steve
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