Last.fm scrobbles don't complete on a stream with crossfade?

[woodruffw]

First of all, thank you for creating and maintaining Liquidsoap! It's an incredibly cool tool, not to mention fun to use 🙂

I'm opening this because I'm trying to scrobble tracks as they go through my processing pipeline. I'm using lastfm.submit.full like so:

music = mksafe(crossfade(duration=3.0, playlist(playlist_path, mode="normal")))
music = lastfm.submit.full(user=lastfm_username, password=lastfm_password, music)

This results in a "currently playing" scrobble entry as expected, but the "final" scrobble that actually marks the song as fully played never seems to get triggered. Consequently, when the next song begins, the previous "currently playing" entry disappears entirely.

I haven't fully debugged it, but it appears to be caused by the crossfade processing phase. When I do this instead:

music = mksafe(playlist(playlist_path, mode="normal"))
music = lastfm.submit.full(user=lastfm_username, password=lastfm_password, music)

...the scrobbles appear to be persisted correctly. However, it'd be really nice to use it with crossfading!

Alternatives considered

Using on_metadata + lastfm.submit also works correctly, even with the crossfade:

music.on_metadata(fun(m) -> lastfm.submit(user=lastfm_username, password=lastfm_password, m))

However, this only provides the "last played" last.fm record, not the "currently playing indicator." So it's a partial workaround 🙂

[toots]

Hi @woodruffw ! Glad you're enjoying the tool!

Crossfade transitions will remove track marks, for instance when doing crossfades, which will break certain behavior that rely on waiting for a track to be finished.

The easiest solution should be to insert the operator between the playlist source and the crossfade:

music = playlist(playlist_path, mode="normal")
music = lastfm.submit.full(user=lastfm_username, password=lastfm_password, music)
music = mksafe(music)
music = crossfade(duration=3.0, music)

[woodruffw]

Thanks for the fast reply!

That is indeed an easy solution -- I'll give it a try tonight, thank you!