[mythtv] prebuffer audio related?

Steven mythmail at richardstraat.homedns.org
Thu Oct 28 08:12:20 UTC 2004

  > I still can't see what audio driver you are using?  Intel ICH is iffy
> for example

It's the audio chip onboard the ATI9100IGP chipset and it uses the 
atiixp alsa driver.
> You appear to be recording at 44Khz.  Can you try recording at 48Khz and 
> see if this helps?
> What are you using as an amp?  Is it spdif connected to an AV amp?  What 
> does the amp say about output rates?
I have a Sony receiver connected with spdif and it says PCM 48 on the 
display when playback starts.
I was indeed recording at 32Khz (wich is the default MPEG2 settings I 
believe?) so I changed to 48Mhz and now the skips are less frequent and 
also less noticable.
2004-10-28 09:10:47 Changing from None to WatchingLiveTV
2004-10-28 09:11:51 prebuffering pause
2004-10-28 09:13:03 prebuffering pause
2004-10-28 09:15:03 prebuffering pause
2004-10-28 09:15:05 prebuffering pause
2004-10-28 09:23:14 prebuffering pause
2004-10-28 09:23:23 prebuffering pause
2004-10-28 09:24:55 prebuffering pause
2004-10-28 09:25:02 prebuffering pause
2004-10-28 09:26:24 prebuffering pause
2004-10-28 09:33:44 prebuffering pause

Using /dev/dsp Av sync is perfect. Using ALSA:spdif or ALSA:pcm.front 
audio is a little behind but no prebuffering pause at all.

> I'm thinking that there is some kind of resampling going on here, and 
> the audio driver is broken and not reporting free space correctly?
Probably so.
But playing back the recordings with 32Khz audio in them with mplayer 
also gives me PCM 48 on my receivers display but the file plays fine.

> Ed W

Thanks for your help.


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