[mythtv-users] ALSA and SPDIF Out For nForce2 Motherboards

KianTeck chua_kianteck at yahoo.co.uk
Mon Apr 19 04:26:47 EDT 2004


Anybody got solutions for the following problem?


KianTeck wrote:

> Michael T. Dean wrote:
>> That's the problem.  The section that I just had you change was the 
>> section that defined a device called "default" (not called 
>> "dmix-digital").  In other words, the default device is the device 
>> used when no device is specified (i.e. a program uses the ALSA API 
>> but doesn't request a specific device) or when the "default" device 
>> is requested (i.e. for Myth, "ALSA:default").
>> I suppose I should have included a nice comment at the top of the 
>> .asoundrc listing all the valid devices defined within.  Anyway, the 
>> only devices you should ever use are:
>> analog
>> mixed-analog
>> digital
>> mixed-digital
>> default
>> Note that if you leave the entire definition of "pcm.!default" 
>> commented, default will be identical to analog.  If you redefine 
>> default by uncommenting the 4-line definition of "pcm.!default" 
>> default will be identical to the device associated with the 
>> uncommented slave definition (mixed-analog, digital, or mixed-digital 
>> from top to bottom as shown in the .asoundrc I posted at 
>> http://www.gossamer-threads.com/perl/mailarc/gforum.cgi?post=119212&t=search_engine#119212 
>> ).
>> All other names in the .asoundrc--including "dmix-digital" are for 
>> internal use only--they are virtual devices created as aliases to 
>> allow reuse within the file.
>> So, try using "ALSA:digital" or "ALSA:mixed-digital" and see how it 
>> works.  (Or you could use "ALSA:default"--if you leave your .asoundrc 
>> as is (based on the change you just made), this will be the same as 
>> using "ALSA:mixed-digital")
>> Mike 
> No joy again.  This is part of my .asoundrc as advised:
> ------------------ <snip>----------------------
> pcm.!default {
>  type plug
> ## Uncomment the following to use mixed analog by default
> #  slave.pcm "dmix-analog"
> ## Uncomment the following to use unmixed digital by default
> #  slave.pcm "digital-hw"
> ## Uncomment the following to use mixed digital by default
>  slave.pcm "dmix-digital"
> }
> ------------------ <snip>----------------------
> I changed the "Audio Output device" in mythtv to "ALSA:mixed-digital" 
> and tried to watch live TV again.  This is what the mythfrontend says:
> ------------------ <snip>----------------------
> Opening ALSA audio device 'mixed-digital'.
> Unable to set hw params for playback: Invalid argument
> Error setting audio params: Invalid argument
> ------------------ <snip>----------------------
> I get the same deal too, as above, if I change the "Audio output 
> device" in mythtv to "ALSA:default".  Anyway, I do not get the "Device 
> or Resource busy" message in both the above settings now.
> Setting .asoundrc in mixed digital, while live TV is running, and 
> issuing "aplay /usr/share/sounds/KDE_Startup.wav" (via ssh) run 
> immediately without any queuing.
> I also noticed TWO other settings in mythtv audio setting (Setup | 
> General | Audio) "Mixer Device = /dev/mixer" and "Mixer Controls = 
> PCM".  Do I  need to change any of one of these 2 values?
>> BTW, that also means that there wasn't necessarily another program 
>> using your audio device.  Therefore, you can try both "ALSA:digital" 
>> and "ALSA:mixed-digital" and use whichever you prefer.  I recommend 
>> testing by watching some TV and causing the computer to play other 
>> noises (i.e. ssh to the computer and issue an aplay) to see how sound 
>> behaves.  If using "digital," the sounds will "queue up" (most likely 
>> causing the application waiting for sound--here aplay--to block), but 
>> if using "mixed-digital," the sounds will play (so the applications 
>> won't block).
>> Also, when you finish watching TV with unmixed output, you'll hear 
>> all the sounds that got queued up--on my system, they play back much 
>> louder than my videos, so it's quite scary to stop a playing video.  
>> Because of that (and because the other sounds usually mean 
>> something), I'm using mixed output (analog in my case because I'm 
>> hooked directly to the speakers).
>> _______________________________________________
> I believe setting to "ALSA:mixed-digital" in mythtv should be what I 
> want just to avoid surprises/shock at the end of a video session. ;-)
> KianTeck
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