[mythtv-users] VDPAU Audio Issues

[stalks]

Symptom: Audio drops out for half a second at seemingly random 
intervals. Can happen several times a minute, or once every 5 minutes. I 
find that some shows I record are worse than others (my test show and 
worse offender is Friends from channel E4 UK). It happens in not only 
MythTV but also mplayer, xine and xbmc. I post here hoping for guidance.

My setup,
- Intel DP43TF, Q6600, 8GB DDR2, 1x Seagate 7200rpm 250GB, ASUS GeForce 
8400GS, Onboard Intel HD Audio
- Audio/Video output via HDMI (via onboard SPDIF passthrough) to Samsung 
LE40R87
- Debian Linux amd64, running Linux Kernel 2.6.30 setup as "squeeze/testing"
- 3x Hauppauge Nova-T DVB-T Model 909 with 3 MultiRec each
- MythTV Frontend & Backend running from SVN r21236 (latest as of last 
night)

I started using VDPAU in April, had this issue since then, and have 
compiled new MythTV SVN installs on a regular basis using following 
commandline (ccache is installed),
make clean && make distclean && \
svn revert -R * && svn up && \
./configure --enable-vdpau --disable-directfb --enable-libfftw3 && make 
-j4 && \
sudo make install

What I have attempted so far:
- I have tried 3 different graphics cards:
 o XFX 8800GT 512MB
 o ASUS 9400GT 1GB
 o ASUS 8400GS 256MB
- Nvidia drivers 185.18 and 190.18
- Kernel 2.6.28 and 2.6.30
- Aggressive audo buffering on & off (currently off)
- Extra sound buffering on & off (currently on)
- Realtime processing (curently off and run as "mythtv" user)
- Alsa from debian repository (1.0.16) and now compiled alsa 1.0.20
- Disabling VDPAU (this fixes the issue, but is not ideal)

It is only until last night that I realised the problem was VDPAU. I 
needed to disable VDPAU to have unicode subtitles work in XBMC and then 
noticed that there wasn't a single audio drop throughout a film. I then 
changed to the "Normal" profile in MythTV and watched several episodes 
of Friends without any audio problems. Re-enabling VDPAU brought the 
symptoms back again.

With logging on "most" I haven't noticed anything untoward, I can post a 
log if required.

Everything else is perfect. (Audio/Video sync/quality etc.).

Is there a setting/compile option I have overlooked?
Am I alone with this symptom?
What can I do to debug?

Some basic info available at the following URLs:
http://www.nooblet.org/other/jawa-vdpau/dmesg.txt
http://www.nooblet.org/other/jawa-vdpau/lspci.txt
http://www.nooblet.org/other/jawa-vdpau/lspci_vv.txt
http://www.nooblet.org/other/jawa-vdpau/lsmod.txt
http://www.nooblet.org/other/jawa-vdpau/alsa.txt
http://www.nooblet.org/other/jawa-vdpau/nvclock.txt

Regards,
Steve.