Re: audio sink RuntimeError: audio_oss_sink

[Marcus Müller]

Hi Rick,

does it work when you put nothing in the device field? (because that
should select the default audio architecture, ALSA in your case, and use
the default device, which would be Pulse Audio sitting behind "default".)
Using "sysdefault" can normally fail, since that might not be a
shareable device. "default" is really what you'd normally be going for.
A program I like to use to see which programs use Pulseaudio, natively
or through the "default" ALSA device, by the way, is `pavucontrol`.

Best regards,
Marcus

On 14.08.20 00:27, aardric wrote:
> Hail,
> 
>     I am introducing myself to SDR technology and gnuradio through 
> whatever project documentation I find, dissecting the code and executing 
> simple experimental flow graphs to test understanding of concepts, 
> hoping to avoid forum queries (this is my first). Although the audio 
> sink is not critical to my ultimate use of gnuradio and a bit of a 
> diversion I will eventually start digging into it. However, I thought to 
> submit a query on whether there is something obvious I should try in 
> order to get it working. I am using gnu radio companion 3.8.1.0 (Python 
> 3.6.10) and feeding the audio sink with a 1 kHz tone from the signal 
> source block.
> 
> (1) staring with:
> :~> aplay -L
> null
>      Discard all samples (playback) or generate zero samples (capture)
> default
>      Default ALSA Output (currently PulseAudio Sound Server)
> sysdefault:CARD=PCH
>      HDA Intel PCH, ALC892 Analog
>      Default Audio Device
> front:CARD=PCH,DEV=0
>      HDA Intel PCH, ALC892 Analog
>      Front speakers
> surround21:CARD=PCH,DEV=0
>      HDA Intel PCH, ALC892 Analog
>      2.1 Surround output to Front and Subwoofer speakers
> (...)
> hdmi:CARD=PCH,DEV=0
>      HDA Intel PCH, HDMI 0
>      HDMI Audio Output
> hdmi:CARD=PCH,DEV=1
>      HDA Intel PCH, HDMI 1
>      HDMI Audio Output
> hdmi:CARD=PCH,DEV=2
>      HDA Intel PCH, HDMI 2
>      HDMI Audio Output
> hdmi:CARD=PCH,DEV=3
>      HDA Intel PCH, HDMI 3
>      HDMI Audio Output
> hdmi:CARD=PCH,DEV=4
>      HDA Intel PCH, HDMI 4
>      HDMI Audio Output
> 
> (2) using sysdefault:CARD=PCH for the audio sink device name,
> both 44.1 kS/s and 48 kS/s the following runtime error results:
> 
> (3)
> gr::log :INFO: audio source - Audio sink arch: oss
> audio_oss_sink: sysdefault:CARD=PCH: No such file or directory
> Traceback (most recent call last):
>    File "/gnuradio/examples/audiotest.py", line 136, in <module>
>      main()
>    File "/gnuradio/examples/audiotest.py", line 112, in main
>      tb = top_block_cls()
>    File "/gnuradio/examples/audiotest.py", line 78, in __init__
>      self.audio_sink_0 = audio.sink(samp_rate, 'sysdefault:CARD=PCH', True)
>    File 
> "/usr/local/lib64/python3.6/site-packages/gnuradio/audio/audio_swig.py", 
> line 220, in make
>      return _audio_swig.sink_make(*args, **kwargs)
> RuntimeError: audio_oss_sink
> 
>  >>> Done (return code 1)
> 
> (4) Fixing this isn't critical and in time I will get to the bottom of 
> it; the forum query just removes the possibility of an obvious answer 
> that most everyone else knows about. My guess is that I have to disable 
> the Pulse audio server.
> 
> 
> Rick
> 
> 
> 
>