[mythtv-users] My Perennial Problems with XvMC

Mythtified mythtified at extrahip.net
Thu Jan 25 04:51:25 UTC 2007

Hi - wonder if anyone else has noticed this? I am experiencing the exact 
same behavior in my system. When running the BE and capturing HD-3000 
programming, mythfrontend shows heavy pixelation and crackling sound (this 
is SD and is observced with XvMC, straight XV and also with libmpeg - 
mplayer works fine by itself). If I stop Mythfrontend and go to another FE 
system upstairs, the picture is great! Something strange going on with my 
nvidia card and the HD-3000. Others have had similar problems:


I have also posted there as well - I am currently the last post on that 

Any info appreciated...

>On 9/20/06, chris at cpr.homelinux.net <chris at cpr.homelinux.net> wrote:
>> On Tue, Sep 19, 2006 at 08:05:31PM -0600, Norm Dugas wrote:
>> > I would check to make sure it's not a bus issue or a shared IRQ issue
>> > (if you've got AGP and PCI, don't know about PCIe).  Mobo docs should
>> > say something about IRQ assignments.  As for the bus issue, google 
>> > would
>> > be my friend.
>> Note that almost all motherboards physically share IRQ lines
>> between different PCI slots and the mobo resources, so often the
>> only way to put two devices onto different interrupts is to
>> physically move the card to a different slot.  Changing the IRQ
>> assignment for one card won't have any effect as the other will
>> follow it.
>> Once I moved the IDE adaptor to a different slot the problem went
>> away.
>Just did a lot of testing with no real results.
>Weary of a power supply issue, I unplugged the secondary hard drive,
>both CD-ROM drives, and then removed my PCI USB2.0 card and my PCI
>gigabit ethernet card.  This left only the HD-3000, the sound card,
>and the AGP video card plugged in.  I booted and got the same results.
>I then went through and tried plugging the HD-3000 into each of the
>open PCI slots with the same results.  I even tried placing some tin
>foil in between the graphics card and the HD-3000 to block any
>radiation.  Yeah that didn't do anything either.
>I also double checked my old 4200 and it seems I was wrong about it.
>There is no picture deterioration while using XvMC, only many
>prebuffering pauses.  Also, there was no picture deterioration or loss
>in signal lock when scrolling through webpages like before.  So it may
>be related to this new card.
>I suppose I could try removing the sound card, but now that I realize
>it worked with the 4200, I'm not sure it's worth the effort.
>Any way there could be a bus/irq issue with one graphics card over another?

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