[mythtv-users] HDTV/CPU survey

[John Patrick Poet]

On Wed, 28 Apr 2004, Daniel Thor Kristjansson wrote:

>
> Hey John,
>
> I managed to borrow a GeForce 4 MX card and it doesn't give me any
> playback problems using XvMC except with frame skipping and OSD. i.e.
> when there is on OSD playback is fine even on 1080i material. My
> processor is only a 1.7Ghz P4 with 333Mhz DDR-RAM. So I think that
> brings the variables down to compile options, myth settings, or sound
> card.


If I read what you are saying correctly...  You do not get any jitter with
720p or 1080i, even on severe camera pans?  But you do with OSD?

Do you think your FX card works better than the 4 MX?

Have you tried turning on "use video as timebase"?  Do you get full-speed
playback?


> This is with my playback patch, which does require at least i686
> and -O3 compilation to work quickly. (cmov instruction, and branch
> removal really.) With 1080i my patch only displays one field so
> not having deinterlacing isn't a killer.


Hmmm, I will re-try your playback patch and make sure that -O3 is used.  I
believe I have already tried that, but I will double check.  Last time I
tried it, video playback was Okay, but did not seem improved over having
XvMC disabled.  It also caused studdering with any OSD.


> Umm, I've also had problems
> with extra audio buffering with XvMC, though I need it with software
> decoding, go figure.


The extra audio buffering is not typically needed, but without it I
*occationally* get an audio glitch.  I am currently using the onboard
C-Media CMI9739A audio controller with the intel8x0 ALSA driver.  I have
also used an old SB Live! which gave me equivalent performance.  I have all
the audio going out the S/PDIF jack to my pre-amp.


> I'm working on the hdtvrecorder at the moment, I really want to be able
> to get the SAP audio (I'm learning Spanish) and subtitles when
> available. Though text looks pretty complicated with ATSC, two
> different huffman tables just for English, with different tables for
> different countries, and some UTF-16 text sprinkled here and there.
> PMT's that don't agree with PSIP, ugh.


I highly recommend that everyone using the HD-2000 card, use your
hdtvrecorder patch.  Getting rid of the bad packets definitely improves the
playback.

Getting subtitles working would be cool.  I have not desired them up to this
point, but when I watch some British shows, it can be hard to understand
what they are saying sometimes ;-)  Of course, I have yet to see a British
show in HD.

>
> -- Daniel
>

I appreciate the work you are doing on this project.  Sorry I was unable to
help you with your WB audio problems.


John