I'm trying to track down the cause of occasional periods of silence that are happening with my Airtime installation. One thing I've picked up in the logs (ls_script.log) are these: "2013/11/07 19:13:05 [alsa_out(default):2] Underrun!" that seem to coincide with the start or end of every track. Is it something to worry about? Other threads mentioning it asked about whether the installation is a virtual server; it is a VM on an ESXi box, with two cores and 1GB of ram.

I'm have ALSA output enabled, as well as one stream configured, connecting to the local icecast server. When I set the stream to mp3, CPU usage sits at 40%, when I disable it or set it to ogg, CPU usage sits at 17%. When the stream is disabled, the "Underrun!" messages stop.

edit:
Changing from ALSA to OA drops liquidsoap cpu usage to 8%, but breaks it in VLC for some reason (large gaps) whether it's mp3 or ogg.

So is there some issue with encoding streams in mp3, or are these unrelated symptoms?

AIRTIME_SERVER_RESPONDING      = OK
KERNEL_VERSION                 = 3.5.0-23-generic
MACHINE_ARCHITECTURE           = x86_64
TOTAL_MEMORY_MBYTES            = 1019080
TOTAL_SWAP_MBYTES              = 1044476
AIRTIME_VERSION                = 2.5.0
OS                             = Ubuntu 12.04.3 LTS x86_64
CPU                            = Intel(R) Xeon(R) CPU E5-2420 0 @ 1.90GHz
WEB_SERVER                     = Apache/2.2.22 (Ubuntu)
PLAYOUT_ENGINE_PROCESS_ID      = 1232
PLAYOUT_ENGINE_RUNNING_SECONDS = 265675
PLAYOUT_ENGINE_MEM_PERC        = 1.6%
PLAYOUT_ENGINE_CPU_PERC        = 0.0%
LIQUIDSOAP_PROCESS_ID          = 28974
LIQUIDSOAP_RUNNING_SECONDS     = 1577
LIQUIDSOAP_MEM_PERC            = 3.2%
LIQUIDSOAP_CPU_PERC            = 28.9%
MEDIA_MONITOR_PROCESS_ID       = 1227
MEDIA_MONITOR_RUNNING_SECONDS  = 265675
MEDIA_MONITOR_MEM_PERC         = 1.7%
MEDIA_MONITOR_CPU_PERC         = 0.0%
-- Your installation of Airtime looks OK!