Add volume sync between Spotify and AmpliPi

[SteveMicroNova]

What does this change intend to accomplish?

Make it so that Spotify side volume changes are reflected in AmpliPi and vice-versa

Checklist

• Have you tested your changes and ensured they work?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• If applicable, have you updated the CHANGELOG?
• Does your submission pass linting & tests? You can test on localhost using ./scripts/test
• Have you written new tests for your core features/changes, as applicable?

[SteveMicroNova]

This branch depends on #1064 to function in the field

[SteveMicroNova]

I'd like to take note that we stress tested this earlier with multiple people playing tug of war with the volume slider using a Spotify jam and the underlying Spotify stream failed before the script did, according to the logs

It's unclear how the underlying stream failed, and perhaps this is solved with the bump from go-librespot 0.5.0 to 0.5.2, but it's hard to say until we put it through another office-wide stress test (I simply am not able to input enough changes myself even though I am able to create a multi account jam session)

[linknum23]

One thing that we should do is test what the update speed is by logging all of the requests. Realistically we may want to limit the response to 10Hz or something just to avoid overwhelming the Spotify and amplipi APIs.

…

On Fri, Nov 7, 2025, 15:32 Steven Engelbert ***@***.***> wrote: *SteveMicroNova* left a comment (micro-nova/AmpliPi#1063) <#1063 (comment)> I'd like to take note that we stress tested this earlier with multiple people playing tug of war with the volume slider using a Spotify jam and the underlying Spotify stream failed before the script did, according to the logs It's unclear how the underlying stream failed, and perhaps this is solved with the bump from go-librespot 0.5.0 to 0.5.2, but it's hard to say until we put it through another office-wide stress test (I simply am not able to input enough changes myself even though I am able to create a multi account jam session) — Reply to this email directly, view it on GitHub <#1063 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAEZPO5DKNURRH5V2T2M4B333T6W5AVCNFSM6AAAAACKZX53CCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTKMBUHAYDGMZSHE> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[linknum23]

Is this still needed? I thought volume changes were coming in through the volume change fifo?

[SteveMicroNova]

AmpliPi side is handled through a fifo, stream side (Spotify side, airplay side in #1071) is handled through this function that is automatically run as a subthread by the __init__ of this class

[linknum23]

This volume scheme is going to need a pretty diagram somewhere in the code to preserve the sanity of the next person to look at this.

[SteveMicroNova]

How's this (the docstring under VolumeSynchronizer)?

[SteveMicroNova]

Note that the vol sync will not work on systems that are effected by #1067, which are all systems that reboot while playing a persistent stream

[linknum23]

Volume is out of sync and stopped changing from spotify. I think this needs a little more testing.

[linknum23]

Changing volume via amplipis app still works when it goes out of sync