[mythtv-users] Buffer underrun/audio stuttering

Michael Sciscenti sciscenti at gmail.com
Fri Nov 25 13:31:17 EST 2005


Those are good numbers. I'm running at 1920x1080p so perhaps the scaling is
hurting my performance, anything without xvmc is unacceptable performance
wise.

I tried re-compiling the svn version without opengl but no luck, still
getting buffer underruns. Anyone else have any suggestions?

On 11/25/05, Curtis Stanford <curtis at stanfordcomputing.com> wrote:
>
> 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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> >
> >
> >
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>
>
>
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