Echo when playing back MythTV

October 26, 2010

I recently ran into an interesting problem with my MythTV audio. When I played back a program, it would play back with varying degrees of echo in the audio. Usually the echo would be around 100 ms behind, but if I skipped forward or back I could get it up to 3 seconds behind. This problem did not happen outside of MythTV.

First I started with alsa-mixer. There I determined that there was no level I could change to affect the echo. Changing the level always changed both the first audio and the echo.

Next I tried reinstalling the AC97 sound driver, because I saw a website that noted when the driver was corrupt you could get an echo. No dice.

Finally, I happened to be running top, and I saw this:

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 4273 myth 20   0  220m  85m 3588 S   12  8.5  11:55.43 mythfrontend.re
 4257 myth 20   0  245m  85m 3700 S   12  8.5  10:20.79 mythfrontend.re

I had two copies of mythfrontend.real running! Both were getting the lirc keypresses and acting on them. This meant everything (including the player) was being run twice… hence an echo slightly behind the main audio.

Somehow the Gnome session state had been saved with a mythfrontend.real running, and when it was restored it would restore with that mythfrontend.real as well as start a new one. I made sure the session state wasn’t being saved (under Settings), killed all the running mythfrontend.real instances, and then logged out saving the session. Next I logged in and out but unchecked the button to save session on logout. That seems to have done the trick.

Advertisements

Disabling the Ubuntu auto update dialog

October 21, 2010

I’ve lived with the Ubuntu auto-update dialog on my MythTV box for quite a while. Tonight I did a quick search to see how to disable it.

Thanks to this link:
maketecheasier.com/remove-the-annoying-update-manager-pop-up-in-ubuntu-jaunty

… I discovered that turning off the update dialog was quick and easy. Just do:

gconftool -s --type bool /apps/update-notifier/auto_launch false

You don’t even need a sudo, since it’s just changing your user’s config.

No more popups obscuring MythTV! When something is annoying, a ten second web search can be a good thing.