[pulseaudio-discuss] Audio source getting stuck on monitor record

[Georg Chini]

On 26.12.2017 16:33, Daniele Varrazzo wrote:
> Hello, good $TIME_OF_DAY
>
> I am experimenting with interaction between music and coloured lights,
> as you do in these days. So I've set up a Python script to record from
> a PulseAudio source monitor, FFT some audio chunks into a spectrum and
> send it to an Arduino for led goodness.
>
> I am experiencing locks between the recording script and the audio
> source, and while it is totally likely that I am not using the PA api
> correctly, I can easily reproduce the same locking using
> mplayer+pacat. I have experienced locking sometimes on a good laptop
> (an i7 using PulseAudio 8.0 with Ubuntu 16.04) using the pa_simple api
> ,but running the things on a raspberry pi (using Raspbian Stretch and
> PulseAudio 10.0) they are absolutely regular, and moving to the
> asynchronous API didn't help.
>
> In order to reproduce the lock it is enough to record on the source
> monitor in one shell:
>
>      pi at raspberrypi:~ $ pacmd list-sources | grep name:
>               name: <alsa_output.platform-soc_audio.analog-stereo.monitor>
>
>      pi at raspberrypi:~ $ pacat --record -d
> alsa_output.platform-soc_audio.analog-stereo.monitor >/dev/null
>
> ...and run mplayer in another shell, stop it with Ctrl-C, and run it again:
>
>      pi at raspberrypi:~ $ mplayer Cibo\ Matto\ -\ Flowers.mp3
>      MPlayer 1.3.0 (Debian), built with gcc-6.2.1 (C) 2000-2016 MPlayer Team
>      # [...]
>      Starting playback...
>      A:   5.5 (05.4) of 177.0 (02:57.0)  3.4%
>
>      # Hit Ctrl-C here
>
>      MPlayer interrupted by signal 2 in module: decode_audio
>      Exiting... (Quit)
>
>      # Run it again
>
>      pi at raspberrypi:~ $ mplayer Cibo\ Matto\ -\ Flowers.mp3
>      MPlayer 1.3.0 (Debian), built with gcc-6.2.1 (C) 2000-2016 MPlayer Team
>      # [...]
>      Starting playback...
>      A:   0.1 (00.0) of 177.0 (02:57.0) ??,?%
>      Audio device got stuck!
>      A:   0.5 (00.4) of 177.0 (02:57.0) ??,?%
>      Audio device got stuck!
>      A:   0.5 (00.4) of 177.0 (02:57.0) ??,?%
>      # [...]
>
> FYI my python script, in its async incarnation, is at
>
>      https://github.com/dvarrazzo/arduino/blob/89f53ca/tools/alsa2spectrum.py
>
> I would be interested in writing a script reliable enough to run in
> background to digest whatever is played on the device into coloured
> lights. Is it possible? Is there any piece of documentation I have
> missed?
>
> Thank you very much.
>
> -- Daniele
> _______________________________________________
Hi Daniele,

did you also test with PA 11.1? It would be good if you attached a debug
log of pulseaudio for the command sequence above.

I tried but unfortunately cannot reproduce the issue here.

Georg