[mythtv-users] backends without tuners (was Re: Transcoding is being done on frontends, not backend)

Daniel Kristjansson danielk at cuymedia.net
Sat Jan 10 14:06:22 UTC 2009


On Fri, 2009-01-09 at 18:44 -0500, Krzysztof Adamski wrote:
> Every time the "backend without tuners is not supported" comes up, I
> can't stop wondering why not have a network tuner like the HDHR defined
> on this tunerless backend. This would satisfy the requirement for tuners
> without actually having a tuner in the backend.

I've actually thought of defining some IPTV tuners by default when
there is internet access. I soon thought better of it, it would just
be another thing to maintain.

In general a mythbackend running without tuners defined will complain,
but nothing terrible will happen if it is properly configured as a
backend. It will waste memory over running mythjobqueue so it is not a
supported configuration, but only because debugging it adds another
layer of complexity that isn't needed when there is a problem to debug;
like making sure this backend is configured properly.

What is a terrible idea is trying to run a frontend or backend that has
been compiled after passing --disable-frontend or --disable-backend.
Those are hidden ./configure options that were created to make porting
mythtv to new platforms easier. Despite their names, they pretty much
randomly split the libraries in two so you can port just one of those
binaries at a time, but without some of the functionality of a frontend
or backend. Running those binaries is of course not supported, because
they are known to be broken. Only Gentoo offers these as an option and
even Gentoo prints a small warning text somewhere in the millions of
lines of the compile log that using those USE flags will foobar MythTV.

It is useful to have the mythbackend installed. In trunk mythbackend
on the local machine is run by the frontend as a binary to generate
preview images for nfs/samba mounted shares, and it even in 0.21 it
has options, like --testsched, --printsched, --printexpire, --resched
which can be useful. And as mentioned before the binary it self isn't
so big when just sitting on disk. Even if you netboot you will want
to mount the disk with MythTV and other binaries over nfs after the
initial boot.

I'm pretty sure mythtv-setup is not needed for a frontend only machine
in trunk, but I don't know about 0.21. That might be another reason
to install the mythbackend package from your distro, since those are
usually packaged together.

PS As a developer, unless you are distributing MythTV packages or asking
for help with some funky mythtv setup on this mailing list, I couldn't
care one whit how you run MythTV. We try to make the app pretty abuse
resistant. When you go off the reservation, configuration wise, it will
rarely cause mythtv to crash; so it may not work, or features may go
missing, or it may waste memory, but if it works well enough for you
to be happy then it's no business of mine.

-- Daniel



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