Currently, in Roblox, there is no way to create seamlessly looping game soundtracks with custom loop points without uploading multiple files. The only way to do so is if the very end of your track matches the very beginning. Other game engines like Unity allow you to create labels in programs like Audacity that let you define where you want looping to take place. Once the song reaches the “Loop End” label, it wraps back around to the “Loop Start” label. Here is a screenshot of how this would look in a soundtrack I’m using for a game I’m working on:
The only way I would be able to use this file right now is if I had a constantly connected TimePosition listener on the Sound object. This would still not work seamlessly because the rate at which it detects the TimePosition would be up to how many other tasks are being done on the user’s computer. Native support would be the far better option.