[mythtv-users] NVP: prebuffering pause -- what does it mean, really?

Willy Boyd willyboyd at gmail.com
Mon Mar 19 19:32:59 UTC 2007

On 3/19/07, Mike Perkins <mikep at randomtraveller.org.uk> wrote:
> The reason you get the problem after changing channels in LiveTV mode is
> because the back end is closing one file and opening another...writing
> the data to disk, making new directory entries, updating the MySQL
> database etc. I usually get (now) a single hiccup about 2 secs after a
> new channel starts, which is when I assume the disk I/O is getting done.

Right, except that I never get it when a new program starts on the
same channel, and Myth goes through almost all of the same steps there
too (closing one file, opening another, updating mysql, etc).  The
only other significant delay introduced for a channel change must be
the wait for my channel-change script to complete (I'm tuning an
external box).

> I reckon therefore it's something network related. The presence of the
> slave backend, even though it's never used, seems to cause sufficient
> traffic on the network to keep everything greased enough to work
> properly. If I stop the slave backend, the pauses begin again.

Just for comparisons sake, my setup is a combined BE/FE so it's all
local.  Honestly, I might still have it set to use the myth protocol
instead of file access, I'll have to check that later on.  I'm
hesitant to touch anything now that it's all working :)

Judging from the wild variance in "solutions" I found for this very
same problem, it just seems like a common symptom coming from a number
of possible performance issues.  Apparently mine was mysql... others
had to update ALSA, tweak video card drivers, etc.  Just another thing
to try I guess :)

> Oh, and I haven't tuned my mysql setup. Might try that later.

> Mike Perkins
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