Re: audio sink RuntimeError: audio_oss_sink

[Marcus Müller]

Hi Rick,

glad you got it to work, but really, your GNU Radio audio sink shouldn't
use OSS (which only exists as emulation layer atop of ALSA since more
than ten years, I think), when you don't put anything in the device field :)

Best regards,
Marcus

On 15.08.20 04:53, aardric wrote:
> Wow. I didn't expect such a quick response; thank you all.
> I noticed an option in the /etc/sysconfig/sound file:
> # Load OSS-emulation modules at boot-up? (yes/no)
> # OSS-emulation modules are needed if you use OSS applications
> # with ALSA drivers.  This option specifies whether these modules are
> # loaded at boot-time.
> #
> LOAD_OSS_EMUL_MODULES="yes"
> 
> For shits and giggles, I enabled it and found /dsp and /audio directories 
> appeared after I next restarted the system.
> After this, /dsp, /audio and blank work in the device field of the audio 
> sink. The audio sink now works as well as
> pulse audio (so system not broken for general use). The KDE pulse audio 
> controls work with the audio sink although
> pavucontrol& does not (audio sink reports  error: "audio_oss_sink: 
> /dev/audio: Device or resource busy"). I don't
> require pavucontrol so long as the KDE audio controls work.
> Running aplay -L shows no change from before.
> So I am happy to consider this resolved and no long a diversion from other 
> aspects of gnuradio.
> Perhaps in a couple of months I will be able to contribute something useful 
> to the project.
> 
> cheers,
> Rick
> 
>>> Date: Fri, 14 Aug 2020 13:50:51 +0200
>>> From: Marcus Müller
>>> [<mueller@kit.edu>](mailto:mueller@kit.edu)
>>> To:
>>> [<discuss-gnuradio@gnu.org>](mailto:discuss-gnuradio@gnu.org)
>>> Subject: Re: audio sink RuntimeError: audio_oss_sink
>>> Message-ID:
>>> [<c1e99e0b-0146-a0b9-520f-243c9d8b2b3a@kit.edu>](c1e99e0b-0146-a0b9-520f-243c9d8b2b3a@kit.edu">mailto:c1e99e0b-0146-a0b9-520f-243c9d8b2b3a@kit.edu)
>>> Content-Type: text/plain; charset="utf-8"
>>>
>>> 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