[mythtv-users] Vaapi use on Sandy Bridge

[Matt Garman]

On Sat, Jan 28, 2012 at 06:32:34PM -0800, Yeechang Lee wrote:
> Raymond Wagner <raymond at wagnerrp.com> says:
> > If you're only running 15% CPU running the software decoders,
> > why even bother with hardware decoding?  In any case, you should
> > be running the OpenGL renderer rather than XVideo if at all
> > possible.
> 
> I know that part of the argument for having a powerful frontend is
> to have the ability to use software decoding regardless of VDPAU.
> Isn't VDPAU's deinterlacing and rendering superior to OpenGL or
> any other software method, though?

VDPAU with MythTV is of course sweet: easy to use, has a lot of
community support, seems to be stable, etc.  VDPAU paired with a
"real" CPU (i.e. non Atom) and you have a MythTV system that can do
practically anything you could ever want.

However... based on what I've seen, if you want a full-featured
VDPAU system (i.e. able to use the Advanced 2x deinterlacing),
you'll need a GT-430 (or gt240 IIRC) or better GPU, which currently
are only available as full-size, add-on cards (or half-height cards
with fans, or there's the one Zotac board with the integrated
GT430).  But generally speaking, you add size and heat and power
consumption to your system.

If you go with the Ion based systems, you're getting a lesser GPU
which may not be able to give you the quality/de-interlacing support
you want.  Not to mention, if ever there's anything you want to do
that VDPAU doesn't support (Flash?), the Atom will probably be too
wimpy to do it.

At least for me, my big interest in Sandy Bridge is that it allows
you to build a MythTV that meets all criteria:

    - small physical size
    - low power consumption
    - quiet
    - powerful enough to do everything you need
    - low price (depending on your perspective)

For example: I---and many others on various forums---have built
full-capable MythTV (or other HTPCs/media PCs) using MicroITX
motherboards, tiny cases (I use the Habey EMC-800B), and an i3-2100
CPU.  These can easily be made to idle under at under 18 Watts AC.
In most parts of the USA, if run 24/7, this will cost you about
$18/year.

I spent a lot of time trying to make a small, quiet, low power
GT-430 based system, and the best I could do was 30 Watts AC.  Not
to mention, a case that was significantly bigger [1].

If ever it is possible to get VAAPI to have the same features,
quality and stability as VDPAU, then VDPAU becomes kind of
pointless (why would you add addtional cost, heat, power and
complexity when the CPU can do it all by itself?).  But in the
meantime, OpenGL on Sandy Bridge---for me personally---does
everything I need, and looks as good as VDPAU as far as I can tell.

[1] http://www.silentpcreview.com/forums/viewtopic.php?f=14&t=63740

-Matt