[mythtv-users] Static noise from AC3 passthrough

[Michael T. Dean]

On 06/06/2006 03:00 AM, Gabe Rubin wrote:

>I am still curious why, when I set up digital-hw as my default in my
>.asoundrc (I assume that is what I have done), it does not default to
>that setting when I do 'aplay Track01.wav'
>

Probably a small typo in your ALSA config file (assuming you mean you've 
specified that "digital" should be the default by uncommenting the line 
that slaves default to "digital-hw" -- which it sounds like is what you 
mean.  Only reason I'm being picky with the terminology is because if 
you have actually set "digital-hw" as the default, you would get the 
same as below.  Perhaps you forgot to uncomment the line "type plug"?

Hmmm.  I think I'll modify the config to make it easier to understand 
(once I return home this weekend).  Thanks for asking the question, 
though.  Always glad to find ways to improve.

>, instead I need to do
>'aplay -d digital-hw Track01.wav'.  It sounds like what others have
>described as not resampling properly
>  
>

That's exactly what using "digital-hw" should do--send the data through 
directly to the hardware without resampling.

Use "aplay -d digital Track01.wav" for proper playback.

The new comments I added to the ALSA conf file explain that you should 
never use "digital-hw" or "analog-hw" directly--they are for "internal 
use only".

>Seems like that may be the first step I need to tackle -- an improper
>.asoundrc perhaps?
>

Quite possibly.  My recommendation is to start over with the config file 
in the wiki ( 
http://mythtv.org/wiki/index.php/DigitalSoundHowTo#Setting_up_ALSA.27s_.asoundrc.2C_Properly 
--you'll get more descriptive comments than the old version had, so it's 
definitely worthwhile if using an older version), changing the device 
for "digital-hw" (probably the only necessary change) and modifying the 
default as desired.  The config file now starts with "mixed-analog" as 
the default, so changing default only requires commenting that line and 
uncommenting the appropriate other line.

Mike