Impact of "output buffer" size?


I am trying to solve DLNA connection issues and I have read in several posts on this topic that I should reduce the maximum “output buffer” size to avoid virtual memory swaps.

Regardless from my DLNA problems, I’d like to understand the impact of the buffer size. Does it define the maximum duration of a song that can be played at a given sample rate ?

Sorry, if the term “output buffer” is not correct, I use a French version where this buffer is called “Mémoire maxi allouée aux données audio décodées” and I do not know how it states in the English version of the software.

Will it be of any use to increase the installed memory ?

I am a bit puzzled because I currently have 4 GB memory on my Mac Mini and, with the buffer set to 2,4 Gb, my MacOS system monitor indicates that Audirvana uses only around 800-900 Mb (current value on the track the I am playing) and that the total memory used on may MacMini is around 3Gb. So there does not seam to be any shortage of memory !

Still, I do have virtual memory swap syndroms when using Audirvana with Qobuz and DLNA.

My System :
Mac Mini mid 2015 Intel i5 2,5 Ghz
4Gb RAM that I could extend to 8 Gb
2 To SSD drive (third party upgrade in place of the initial HD).
MacOS 10.3.6 High Sierra (mots recent OS available for this Mac)
Audirvana 3.5.50

I don’t know exactly how it works either, but it does seem to affect stability. And it seems that for many people a smaller buffer works better.

I have 16GB of memory in the Mac Mini. Above the 4 GB buffer, stuttering starts to occur. I never have any problems under 4GB. I have also seen users who are around 500MB and then the problems are gone.

If a track is longer than the buffer size, the next part will be loaded halfway through playback. You don’t hear that. You can see it in the progress bar. You will see this loading a bit, music will play. and at some point the bar will continue to load.

If you see that the playback is starting to catch up with the buffering then you can also expect dropouts.

Thank you very much for your quick answer.

My understanding is that reducing the buffer size does not necessarily compromises the length of the track that can be played. That is good news. I will reduce the size of the buffer on my config and test. Since I have a good Internet bandwidth (above 90 Mb/s) and a SSD drive, the buffer load should be quick enough to avoid playback stalling on Lon tracks.

In between, I have made systematic tests to characterize the problem that I am facing when I listen to Highres files from the Qobuz streaming service and a UPnP amp. Since it is very specific to UpNP I will post it under this sub topic.

Best regards