Pulseaudio and musicplayer


I try to get a song being played by a musicplayer with console input. For audio output i use Pulseaudio to send the song to a dlna loudspeaker.

For example: "cvlc /mount/music/song.mp3"

This works perfect as long as i do it in a normal terminal window. But when I try this with the node "exec" I get the error message: "vlcpulse audio output error: PulseAudio server connection failure: Verbindung verweigert (means connection forbidden). So it seems the Pulseaudio doesnt allow connection if i call the music program from node red. If i use ssh from node red to call the program ( it also works. But ssh makes to many problems with connect and disconnect.

Is there any way to fix this and to call a msuciprogram from node red? It can be also a different program like mplayer or similar.

Thanks in advance

Here you can see. On the left is when i start mplayer in a normal terminal. On the right is the same in node-red when starting in xterm. At the bottom you see the:

AO: [pulse] Init failed: Connection refused
Failed to initialize audio driver 'pulse'
Could not open/initialize audio device -> no sound.

Why does it work in terminal but not in node-red? Has it to do with any permission?

This looks like a permission issue. Most probably pulse is running as a different user than the one you run node-red with. You can run pulse in system wide mode but this has some caveats that are for example described here:

Or you have to run pulse and node-red with the same user.


Sorry for the late reply. I tried that out and it worked. Now i am at the point that mplayer is playing the song in the node red with the exec node. I can see it is playing from the debug output but i hear no sound over the dlna speaker. This is the output from the dubug:

MPlayer 1.3.0 (Debian), built with gcc-8 (C) 2000-2016 MPlayer Team

Terminal type `unknown' is not defined.

Playing /mount/musik/alte.mp3.
libavformat version 58.20.100 (external)
Audio only file format detected.
Clip info:
Title: Die alte Hÿhnermutter
Artist: Revolverheld
Album: Giraffenaffen 2
Genre: Unknown
Load subtitles in /mount/musik/

Opening audio decoder: [mpg123] MPEG 1.0/2.0/2.5 layers I, II, III

AUDIO: 44100 Hz, 2 ch, s16le, 192.0 kbit/13.61% (ratio: 24000->176400)
Selected audio codec: [mpg123] afm: mpg123 (MPEG 1.0/2.0/2.5 layers I, II, III)

AO: [pulse] 44100Hz 2ch s16le (2 bytes per sample)

Video: no video
Starting playback...

A: 0.0 (unknown) of 209.0 (03:29.0) ??,?%
A: 0.0 (00.0) of 209.0 (03:29.0) ??,?%
A: 0.1 (00.0) of 209.0 (03:29.0) ??,?%
A: 0.3 (00.2) of 209.0 (03:29.0) 0.8%
A: 0.5 (00.4) of 209.0 (03:29.0) 0.9%
A: 0.6 (00.5) of 209.0 (03:29.0) 0.9%
A: 0.8 (00.7) of 209.0 (03:29.0) 0.8%
A: 0.9 (00.9) of 209.0 (03:29.0) 0.8%
A: 1.1 (01.1) of 209.0 (03:29.0) 0.8%
A: 1.3 (01.3) of 209.0 (03:29.0) 0.8%
A: 1.5 (01.5) of 209.0 (03:29.0) 0.8%
A: 1.7 (01.6) of 209.0 (03:29.0) 0.8%

If I play it in normal terminal window i can see it it the dlna messages that the song is being handed over to the speaker but here nothing. And i have the pavucontrol installed. Same here: When i play the song in terminal i see an input here. With node red nothing. But the song must be played from what i see in the debug log.

Are you sure it’s playing to the right output. Can you specify the output to play too in mplayer?

I could set the output with the option -AO. But it seems to be pulse as standard output. In the text above it can be seen here : AO: [pulse] 44100Hz 2ch s16le (2 bytes per sample)

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