[mythtv-users] High end, state of the art Myth Frontend

[Joseph Fry]

> My Mythfrontend went pop, definitely no magic smoke left inside!
>
> It was a C2D E4300 in an old EVGA Nvidia uATX board with a passive GT640, the graphics card survived but I'm doubtful about the CPU as the supply rail mosfets are very smelly.
>
> So I need to replace it and in an antidote to the myriad cheapest, smallest, slowest, can I run it on a calculator threads… I'd like to investigate what is the very best option for a state of the art high end mythfrontend. There is some stuff on the wiki about de-interlacing quality but it doesn't feel very up to date, I follow the mailing list quite well and I don't recall any quality discussion beyond, does it stutter.
>
> I've compared a few uPnP media player devices and I don't find the same video quality as VDPAU with Advanced 2x de-interlacing.
>
> I do have a ~100" projection screen (1080p DLP projector) and I work in Sports TV so if there's an artefact I'll have seen it and it will have annoyed me. I have almost exclusively HD channels h264 1080i50 and bluray rips but I do get some sports stuff from the states for work which is mpeg2 1080i60, even sometimes glorious 720p60 :-))) I shoot my own sailing video material at 720p60 too, I'm hoping to shoot this at 720p120 next year with a new waterproof camera and new Projector.
>
> I was very happy with the GT640 and vdpau although it doesn't ride through recording glitches very well and it can't play a lot of work material due to 4:2:2 coding or too high bitrate. Of course I use proper gear in proper studios but sometimes it's nice to review things at home or work from here.
>
> The questions:
>
> What is the current best de-interlacer for high motion (sports), is it vdpau advanced 2x or are there opengl equivalents?
>
> If Opengl is an option does it work well with Intel Haswell or Ivy Bridge integrated GPUs?
>
> Is Interlaced output an option with any modern hardware? DLP & eyeballs de-interlace quite well.
>
> Is ffmpeg decode as good as vdpau or better?
> My tests suggest it's similar but vdpau has some subtle noise reduction and cleaner scaling of poor SD material, maybe there are parameters to pass through to ffmpeg to improve decoding?
>
> How much CPU is enough CPU for h264 1080i50, 1080p decoding?
> I suspect that a fast i3 is plenty and that more cores in an i5 is not so useful but??
>
> I do have a i7-860 currently running the backend and a few other things which could get replaced but that does seem overkill.
>
> All input gratefully received, interested to know what developers use too.

A "state of the art" system these days is virtually any modern Intel
or AMD PC.  It's hard to buy a modern, full power processor (not Atom
or ARM) that can't handle decoding of most anything in software (even
celerons can do that).  RAM really doesn't matter much for playback,
just responsiveness in the GUI/OSD.

While an updated NVidia card might get you slightly better output in
VDPAU, I kinda doubt it... you may want to invest in more processor
and see if you like what can be done in software alone better.  There
are a lot of switches that can be added to do additional post
processing in software, and Yadif 2x or Greedy High Motion 2x
deinterlacers, may out perform VDPAU Advanced 2x on some content.  If
your display has a high end video processor in it, or can display
interlaced content well, you might simply output the native signal and
let the display work its magic; this is what I would do with a CRT
projector, not sure about DLP though I suspect a high end projector
may do better than any software or VDPAU solution.

Finally, as you get into high framerates, you might find yourself
limited by your Nvidia hardware and VDPAU... you will definitely want
enough CPU to render and post process the video in software if you
know you will be doing that in the future.

You can certainly use the integrated HD graphics on an Intel CPU if
your doing all of your processing in CPU.  At that point it's just
doing 2D graphics, so as long as it will do the resolutions and frame
rates your interested in, it should work fine.  And you don't need to
use OpenGL... I believe all it really does is scaling and
composting/overlay in hardware (though there may be other
advantages?).  Again if you have a high end display, you may just want
to feed it a native signal and let it scale for you rather than doing
it on the frontend.

As for CPU... I have found that more cores isn't always better, at
least for a front end.  I still have one of the late model Pentium 4
3.2 (or 3.4) GHz cpus doing software decoding and presentation...
works fine for just about everything.  I don't think you will go wrong
with an i3 or even a Sandy/Ivy Celeron for standard materials... I
have a G540 Celeron in my backend and before I started using VAAPI, I
didn't have a problem playing anything, even while the system was
recording and doing commercial flagging.  High framerate stuff might
need a bit more CPU, so I would either get an i3 or wait for the
Haswell Celerons.