[popcornmix]

I apologize for the long post, but I think today I found something out, which might be interesting for other people, who always have been unsatisfied with libreelec's crossfade between tracks and/or gapless audio playback in general:

Interesting. Can you provide your test file? What is its sample rate?

Does changing system/audio/Audio Output Latency make a difference?

It may be CPU related. Presumably there is some period of time between decoding the last sample of the first file and opening the new file, decoding and resampling and submitting its audio. If this takes longer than "Audio Output Latency" then you will get a gap.

But there may be other possibilities. I'm not sure if the resampler gets closed/opened between tracks, and if it does whether some context is lost causing a glitch.
Maybe the lower quality resampler has a smaller filter and hence less context.

It may be possible to avoid resampling. Set "Output configuration" to fixed and "Limit sampling rate" to match your audio file. What does that do?