[mythtv-users] Requirements for reliable HD picture in picture

[Tom Dexter]

I was playing around with picture in picture since upgrading to
0.21...mostly out of curiosity...hardly a necessity for me.  I never
did much with it in 0.20.2 as it didn't seem too reliable and would
occasionally crash the frontend.

I was curious what others have found as far as the requirements for HD
picture in picture.  All my recordings are OTA DVB.  Here's what I'm
finding so far:

As long as at least one of the two broadcasts is 720p I seem to be OK.
 If I try to use PIP with two 1080i broadcasts I start getting
prebuffer paues etc:

2008-04-22 11:39:40.308 NVP: Video is 3.52356 frames behind audio (too
slow), dropping frame to catch up.
2008-04-22 11:39:40.323 NVP: Video is 3.58674 frames behind audio (too
slow), dropping frame to catch up.
2008-04-22 11:39:40.339 NVP: Video is 3.50674 frames behind audio (too
slow), dropping frame to catch up.
2008-04-22 11:39:40.354 NVP: Video is 3.31187 frames behind audio (too
slow), dropping frame to catch up.
2008-04-22 11:39:40.369 NVP: Video is 3.03087 frames behind audio (too
slow), dropping frame to catch up.
2008-04-22 11:39:40.695 NVP: prebuffering pause
2008-04-22 11:39:40.695 NVP: Waiting for prebuffer.. 0
AAAAAAALAAUAAAAAAAAAAAAAAALAALA
2008-04-22 11:39:40.839 NVP: Waiting for prebuffer.. 1
AALAALAUUAULAAAUUAAAAAAAAAUAAUA

...and the picture and audio suffer from occasional pauses.  My CPU(s)
(3 Ghz Pentium 4 w/hyper-threading) never go to less than 20% idle,
and memory usage etc looks fine.   This is on a 100BASE-T wired lan,
not Gigibit...though I'd think that should be fast enough with nothing
else accessing the backend.

What's my most likely bottleneck there?  Thanks in advance.

Tom