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
