[mythtv] live TV stuttering

Ed Wildgoose lists at wildgooses.com
Tue Apr 6 12:55:21 EDT 2004

Hamish Moffatt wrote:

>I'm having a problem with live TV where Myth will start "stuttering".
>It'll start within a second or two of changing to a channel, else it
>will be ok. The audio and picture will pause then resume, over and over.
>I can always fix it by quitting back to the menu and going straight back
>to live TV (which goes to the same channel). I can usually fix it by
>switching to another channel and back again.

This is DVB right.  This is a known issue and is probably sound card 

I think if you test you can demonstrate that if you start tv on a 
channel with a 48Khz audio signal and then move to one with a 32Khz 
signal you will be OK.  But if you start livetv on a 32Khz channel and 
then move to a 48Khz channel it will start to stutter.

You "fix it" by quiting back to the main menu and then coming back in 
again.  Well, what has happened is that you went back in on the 48Khz 
audio channel and the sound card was re-initialised correctly.

Clear as mud?  Your mileage may vary and perhaps you can't ever cleanly 
switch between 48Khz and 32Khz audio modes...?  In my case it is only a 
problem if I start up with a 32Khz mode.  I speculate that the audio 
device is only opened once, and rate changes downwards work, but not 
upwards on my card...  However, I haven't had time to investigate - 
perhaps someone could add some debugging into audiooutputoss.cpp and see.

In all the above I call them channels, but of course on any given 
channel some programs will be broadcast with audio at 32Khz, and some at 
48Khz (usually the really old stuff is at 32Khz), so translate appropriately

Good luck

Ed W

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