Mess With the Clock

The duration picker shows up in the autoscroll menu (y'know, that menu nobody asked for) as the default tab when you first tap the autoscroll button in the live bar, OR when you're tap-hold-interrogating the button to tweak a song that already has autoscroll set up. You can also dig it up from the Metadata Editor hiding inside the Song Editor. ZOMG, so many places to find the same thing!

Autoscroll Stuff (Because We Love Options)

Tap that wrench icon & boom — a screen pops up lettin' you mess with autoscroll settings. Tap Done to lock in your changes & bounce, or tap Cancel to chicken out & lose everythin' you just did. Your choice, chief.

Actually Pickin' a Duration (The Fun Part)

Drag your finger left & right to set the time. Totes quick & easy. Wanna get all precious & fine-tune it? Tap the left/bottom or right/top sides to add or subtract one bleepin' second at a time. Living dangerously, amirite?

When you're done playin' around, just close the menu & your song duration gets updated automatically. If autoscroll is already runnin' when you change stuff, it'll speed up or slow down on its own to match your new duration. Fancy, right?

The duration picker lets you set literally ANY duration. Zero it out or go negative & the duration setting just… vanishes. Poof. Gone. (Probably not the intended use case, but hey, we're not stoppin' ya.)