[mythtv-users] Current wisdom on PVR-150/250/350/500

[Jeff Simpson]

> No, Mpeg decoding is not the entire reason for picking a 350 over the 150.
> There's also TV-Out, which seems to work fine from my limited testing --
> and that includes fastforwarding.

If you're not using the mpeg decoding, you're not getting anything a
$20 nvidia card won't get you.

You may well be the only one. Read up on the multiple threads and open
tickets about fast-forwarding not working when using mpeg decode mode,
and the jittering output when encoding and playing with XV at the same
time.

> > change the speed/location of the currently playing mpeg. It's just a
> > decoder, not a player). framebuffer borks on anything that isn't plain
> > old 2D and slow-motion. Oh, and it takes out your console when it
> > goes, too.
>
> No it doesn't. :-)

Ok, I admit, it's only in rare cases, but it happens often enough to people.

> I'll be hacking at this in the coming weeks, but so far I see nothing that
> might prevent me from running my normal X desktop on the system video card,
> and a second instance of X running off PVR-350's framebuffer, that uses the
> IR receiver as input, and runs _ONLY_ myth.

That's my current setup. Here are the problems I ran into:

In xorg pre-6.9, you can only have one active output at a time. That
means that if you switch to the "normal" x session, the pvr-350
x-session stops displaying, and vice-versa. Also, when you switch to
the myth x-session, the monitors turn a cool collection of pinks and
purples (but it does work).

The good news is that the mpeg decoder still works when you switch to
the "normal" x session, so you can watch tv with the remote while
using normal X. If you want to use the framebuffer (ie, the menus),
you need to switch to that terminal.

In xorg >6.9, you can use "sharevts" to allow multiple x sessions to
be active at once. It works, it will use both sessions at the same
time, myth listens to just the remote, x listens to the keyboard and
mouse. HOWEVER: the xdriver / framebuffer eats up 99% of the CPU, with
no known resolution. I assume it has something to do with the fact
that it's a framebuffer and not a real video card.

> My goal is to get X kicked off on the framebuffer early during boot, running
> myth as the client, with the rest of the boot continuing normally into gdm,
> and my normal desktop.

> The tricky thing here is squaring away the X inputs.  Even if I do not set
> up any InputDevice, Xorg grabs the mouse using its default built-in
> configuration.  I don't want it to do that.  The mouse, and the keyboard, is
> for my main X desktop.

-sharevts is the solution. But like I said, it doesn't yet work right.

> The apparent misconception here is that the PVR-350 is an all-or-nothing
> deal.  That's not true.  Certainly the PVR-350's framebuffer is not a
> substitute for a regular X desktop.  Nobody said that it was.  The only
> thing you need the PVR-350's framebuffer for is to run myth off it, and so
> far you don't need 3D accel for that.

My point was that a mythbox is NOT a PVR. It's a "mythical convergence
box", a box where you do anything / everything related to your
computer, media, tv, etc. If you just want to watch TV, the PVR-350
works great. There's just SO MANY other things that are great with
mythTV, why limit yourself?

And yes "so far" is the key word. I see no reason why myth wouldn't go
to 3D acceleration, and there aren't currently any myth developers who
develop for the capabilities of the PVR-350, so unless somebody jumps
up to the task, the development will continue off into the "doesn't
work on the 350" land.

and if you want multiple x-sessions at once, you can still just get
multiple video cards, that's always worked.