Stereo Tool

Hi

I am experimenting with uMPX using Windows encoder (ST 9.91) and rPi4 decoder (two in fact!) on a local network.

On both decoders I am getting errors every couple of minutes (mainly at different times) saying things like 'Buffer out of range (25.19% / 1522ms full) - resetting' and 'Packets arrived too late 1.500 Seconds of silence'

Any ideas what might be causing this (or better how to cure it!)

Thanks

Ron

Further testing reveals a few clues …

Looking at the GUI on the rPi4 decoder, the green line on the ‘Stream’ graph slowly reduces from the set delay level until it gets to half the value then the Buffer error and audio loss occurs. The delay is then restored to the set value and the pattern repeats

Altering the delay on the uMPX settings changes the values i.e. a 2 second delay will cause the issues when the stream delay drops to 1 second. a 4 second delay will cause the issues when the stream delay drops to 2 seconds etc.

Anyone?

Hi, sorry for the slow response! There are 2 possible causes, each of which should cause an error to be shown somewhere.

Since it affects both decoders, most likely, the encoder isn't sending data at the correct speed. This can be the case for example when using Virtual Audio Cable or VB Cable somewhere in the path.

It could be the Pi's as well, but if it's both, that's very unlikely (unless you're using the same type of sound card on both, and it's one that we haven't tested).

If it happens every few minutes, then the speed offset must be quite large. Most sound cards are within 0.001%, and MicroMPX will compensate for offsets up to 0.02%. Every few minutes would point at an offset somewhere in the range 0.2-0.5%.