Pop/Click between tracks when streaming with VLC

[Rettw78]

I am using VLC for a outdoor audio system consisting of 3 ethernet attached Raspberry Pi2 "player" machines with USB sound cards, streaming 160Kbit/sec MP3s from a server machine/pc running vlc.

The server is running Archlinux x86-64 with recent system packages, using arch VLC-2.2.2 package, and the Pi2's are running Archlinux ARM with vlc 2.2.1 version packages.

The server is a hexacore Haswell-E machine with 16G of RAM that is mostly idle. What is happening is that every so often when listening to the stream from the server, there is a short loud pop, or screech between tracks but its occurance is very infrequent and random. All players seem to have the problem at the same time, and I have heard the same issue when using Archlinux or WIndows PCs with vlc listening to the same stream, so I believe its happening across all platforms, and I believe its being caused by the vlc doing the streaming and not the playback vlc instances. There doesn't appear to be any relationship to any particular songs and when it happens since the stream is a random playback of 4000+ songs.

Here is the command line the server uses for the streaming side:

vlc -I dummy --extraintf=http --http-host 192.168.0.14 --http-port 9090 --http-password '255367' -Z /srv/export/multimedia/audiomix/00-playlist-easy.m3u --sout '#standard{access=http,mux=ogg,dst=192.168.0.14:8080}' --sout-keep

The http interface piece is used so I can query the current track info from a bash script on the server, problem is still evident when I don't use the --extraintf or --http parameters.

The Pi2 units use the following command line to tune in and playback the stream:

vlc -I dummy --quiet http://192.168.0.14:8080 &

I have seen a post from 6 years ago mentioning something similar, and it seemed like it was sound settings on the OS that was doing the playback. The pi units don't have any sort of DE running on them (just plain old ALSA support), so I am not sure that anything in that article applies as it seems that it was system sound setting events that was the issue.

Wondering if anything can be done about this or if anyone else has noticed this issue. Many years ago I used VLC for streaming audio for LAN parties using mostly the same MP3 list, and almost identical commandlines for the the server and players and never noticed this (I think I was using a Pentium3 700Mhz laptop running Redhat 9 at the time for the server with VLC 0.9.x at the time).

Any assistance or ideas on how to fix this would be great..

Thanks,

Rett