AlphaSynth is stuck when playing at slower/faster tempo

[mrcperello]

Is there an existing issue for this?

• [X] I have searched the existing issues

Current Behavior

The player/scrolling has severe hiccups on a specific GP file.

Expected Behavior

Player and scrolling work flawlessly regardless of the playback speed selected.

Steps To Reproduce

1. Open the file attached at https://alphatab.net
2. Enable count in
3. Change playback speed to 0,75 or any other speed different than 1x
4. First play sometimes it goes almost okay but the second time the player is fully un-responsive and broken

Link to jsFiddle, CodePen, Project

No response

Found in Version

1.2

Platform

iOS (WebView)

Environment

- **OS**: iOS 15/16, macOS 12/13 WKWebview
- **Browser**: Safari Version 16.0 (17614.1.19.1.5, 17614)

(We see issues as well on Android (Chrome) and other browsers like Firefox and so on.

Anything else?

On our implementation We face issues when rendering the 3rd and 4th bars of the whole file.

The duration of the first bar duration but the consequent ones are correct (we play in loop multiple repetitions).

The bar duration based on tempo is: At 60BPM: 4s At 72BPM: 3.33s (1.2x) At 48BPM: 5s (0.8x)

And the player has a different duration when setting the tempo to 72 or 48: At 72BPM the first bar plays at 2.13s and then at 3.33s At 48BPM the first bar plays at 7.16s and then at 5s

On the AlphaTab website We cannot select to render only the 3rd and 4th bars so we render the whole file but still but we see some issues when changing the playback speed.

The cursor gets stuck and the sound is silent.

⚠️We cannot reproduce this in any other exercise and we would love to understand what is the issue.⚠️

Unresponsive-or-unexpected-playing-behaviour.gp.zip