Unknown PCM cards.pcm.front

Unknown PCM cards.pcm.front

[Rick Mann]

In my custom cape for Beaglebone black, I'm able to play audio reasonably well. But for one situation when my C++ app (which plays via libao) opens an output, this is written to my app's output:

	"ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.front"

Googling, I found this advice:

	http://alexpb.com/notes/articles/2012/11/14/error-when-playing-audio-on-raspbian-on-a-raspberry-pi/

Which works.

My question is, why do I get it only in this instance? Is it because I might be opening the audio device twice simultaneously? That's about the only thing that might set this situation apart from all the others.

TIA,

-- 
Rick Mann
rmann@latencyzero.com

Re: Unknown PCM cards.pcm.front

[Clemens Ladisch]

Rick Mann wrote:
> "ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.front"

This means that some code tried to open device named "front", and that there
is no such definition for your hardware.


Regards,
Clemens

Re: Unknown PCM cards.pcm.front

[Rick Mann]

> On Oct 29, 2015, at 05:47 , Clemens Ladisch <clemens@ladisch.de> wrote:
> 
> Rick Mann wrote:
>> "ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.front"
> 
> This means that some code tried to open device named "front", and that there
> is no such definition for your hardware.

Thanks, Clemens,

Here's my code that opens the device:


    int driverID = ::ao_default_driver_id();
    ao_sample_format format = { 0 };
    format.bits = 16;
    format.channels = inNumChannels;
    format.rate = inRate;
    format.byte_format = AO_FMT_LITTLE;
	
    mDevice = ::ao_open_live(driverID, &format, NULL);
    if (mDevice == NULL)
    {
        LogDebug("Error opening output device");
    }

I'm not sure where the change in default device would come from.

-- 
Rick Mann
rmann@latencyzero.com