[mythtv-users] SPDIF, Stutter and Query for where to look for
more help
Michael T. Dean
mtdean at thirdcontact.com
Thu May 5 01:50:08 UTC 2005
daworm at comcast.net wrote:
>>Extra audio buffering:
>>...
>>(Has no effect unless you're using a PVR-x50 and similar, and would only
>>make a difference on dark scenes.)
>>
>>
>Ok, I don't think that is a problem. I am capturing mostly via firewire. I also have a PVR-250 for any SD programs that conflict (and HD has priority), but I haven't noticed any crackly audio.
>
>
>>Aggressive Soundcard Buffering:
>>...
>>(Is almost defintely not what you--or anyone else--want.)
>>
>>
>Ok, so I'll leave both settings off. Easy enough!
>
>
Actually, you will want the Extra audio buffering turned on (it should
be on unless it causes problems). And, since you have a PVR-250, you
will see problems during dark scenes without it (but until you cure your
current problems, the problems this fixes are lost in the noise). I was
just trying to point out that these were not the causes of the problems
you're describing.
>>So, you do need to fix your .asoundrc.
>>
>>
>Yes, I had come to the same point, and made those changes (hw:0,4 was the only needed change to point to the digital out on this Intel board). Unfortunately, it didn't help.
>
>
Are you still using ALSA:spdif? That will not work. spdif is an alias
that sends the stream directly to the digital output (on your card,
hw:0,4)--which is expecting 48000Hz PCM (for PCM, that is--AC3 would
also work, but you won't get that from NTSC broadcasts). You'll need to
change it to ALSA:mixed-digital or ALSA:digital or uncomment the
appropriate lines of the .asoundrc to set your default output and use
ALSA:default. Note that if using OSS emulation, you'll need to set the
default output appropriately (meaning you might as well set it).
>>>P.S. I suppose there are four other possibilities for stutter. One, I
>>>used Jarod's guide suggestion to make mythfrontend run as root, but
>>>for some reason mythfrontend still says I need to SUID as root for
>>>smoother playback.
>>>
>>>
>>as root:
>>chmod a+s /usr/local/bin/mythfrontend
>>
>>(In section "Enabling real-time scheduling of the display thread." at
>>http://www.mythtv.org/docs/mythtv-HOWTO-5.html#ss5.4 )
>>
>>
>On FC3, the "local" part does not apply, correct? I think what I did didn't have the "a" (only the "+s") so I'll try that when I get home.
>
>
If you're using a packaged version of MythTV, it's generally installed
in /usr; whereas a compiled-from-source version is typically installed
in /usr/local. Therefore, for your configuration:
chmod a+s /usr/bin/mythfrontend
>>>Two, my video sync is still USleep, as I can't run 7174 (see previous
>>>post about "split-screen" effect) and can't get OpenGL to run on 6629
>>>(crashes X when I run glxgears).
>>>
>>>
>>Shouldn't make that big of a difference (although I recommend fixing
>>your driver installation, anyway).
>>
>>
>I wish I knew how. I've installed 6629, 7167 and 7174 and the first does not allow any OpenGL apps to run, and the latter two both have the split screen problem. I have a GF2 card I can try, but would rather use the FX5200 as I have mostly working modelines that took forever to get right. But, if I must, I must. After building this box over nearly two years, what's a few more weeks to get another video card, right?
>
>
GF2 would probably have the same problems. It's probably because of
using the wrong GL libraries (i.e. the ones in X instead of nVidia's),
but that's a whole different thread... :)
>>Regardless, you'll want to fix your audio, anyway.
>>
>>
>Yes. I don't know whether the AD1985 on this Intel board is a hardware or software card.
>
Software. It uses the same driver as the nVidia nForce.
>Considering it mentions AC'97 I would think it may be software based, which would mean I'd be better off just getting a new card
>
I wouldn't necessarily say that's true. Audio processing tends to
require little effort from modern CPU's. Once you configure yours
correctly, it should work fine.
>(I have open PCI slots, although it would mean having three cards adjacent, which isn't great for airflow. I don't really want to spend too much on a card. Is the Hercules Digifire card hardware based? Or should I bite the bullet and get an Audigy?
>
Don't know about the Hercules. The only hardware ones I have are SB
cards with the Emu10K1, but I haven't bought a discrete sound card in 6
years, so...
Mike
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