[mythtv-users] Buffer underrun/audio stuttering

[Curtis Stanford]

Just Standard decoding and Bob de-interlacing, extra audio buffering  
with ALSA:default. Not using OpenGL sync. Only uses 40-50% CPU  
playing 1080i or 720p. I'm outputting to the DVI port to a native  
720p HD set.

On Nov 25, 2005, at 9:18 AM, Michael Sciscenti wrote:

> Thanks, but I have it even with XVMC off (plus HD video is doesnt  
> play smoothly at all without xvmc for me). What settings are you  
> using with XVMC off that youre able to watch HD content?
>
> On 11/25/05, Curtis Stanford <curtis at stanfordcomputing.com > wrote:
> On Nov 25, 2005, at 12:02 AM, Michael Sciscenti wrote:
>
> > I've tried to avoid emailing the list until I was absolutely sure I
> > couldn't get any further without help.
> >
> > I'm trying to get a Mythtv frontend/backend server up and running
> > on a P4 2.8 GHz box with 1 GB RAM and Nvidia Geforce 6800. HDTV
> > over firewire is what I'm having trouble with. I can now reliably
> > connect to the cable box and get HDTV streams using test-mpeg2 and
> > in Mythtv itself, however I've been completely unsuccessful at
> > solving my audio stuttering problem. I've tried every combination
> > of settings and every little suggestion I could find on the
> > internet and this list yet I still get the following errors:
> >
> > 2005-11-24 04:33:52.663 audio waiting for buffer to fill: have 2048
> > want 4096
> >
> > or
> >
> > 2005-11-24 04:33:54.567 WriteAudio: Preparing 4096 bytes (1024  
> frames)
> > 2005-11-24 04:33:54.568 WriteAudio: buffer underrun
> >
> > Things I've tried but none have gotten rid of the stuttering:
> > ALSA, OSS emulation through ALSA, an asoundrc is present, Xvmc on/
> > off, deinterlacing (bob) on/off, extra sound card buffering on/off
> > (the TV settings option), agressive buffering on/off (in General
> > settings), priority process on/off, etc, you name, I've tried it.
> >
> > The problem exists in both the current release of mythtv and svn
> > from two days ago. I'm running Gentoo. Does anyone have any
> > suggestions?
> >
> > My configure setting:
> > ./configure --disable-distcc --prefix=/usr --mandir=/usr/share/man
> > --disable-altivec --disable-xvmc-vld --disable-directfb --disable-
> > audio-oss --disable-directx --enable-firewire --disable-audio-jack
> > --disable-joystick-menu --enable-lirc --enable-xvmc --enable-opengl-
> > vsync --enable-xv --enable-x11 --enable-proc-opt --disable-dbox2 --
> > disable-ivtv
> >
> > Also of note, I'm using a PCI firewire card that has a VIA chipset.
> > Some have said there are issues with these, but I dont think its
> > the source of my problems since I'm able to grab streams fine using
> > test-mpeg2 and they playback perfectly in mplayer using xvmc. My
> > motherboard is a SiS chipset.
> >
> > Any help would be awesome, I'm about at my wits end and starting to
> > look at other platforms, but really would like to stick with myth
> > if possible. Thanks.
>
> I had the same problem with XvMC on. Works fine with it off, however.
> I'm using FX5200 and P4 2.4GHz and firewire on DCT-6200.
> By the way I also have a cheap $20 PCI firewire card with the VIA
> chipset and it works fine. Sometimes, my node switches on me (0 to 1
> or 1 to 0) for no apparent reason, but otherwise it works well.
>
> Curtis
>
>
>
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