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I want my scrollwheel back!


Two steps forward, one step back. That’s how I feel about the crappy media scrubbing interface built into the iPhone, iPod touch, and I guess pretty much all touch screen-based media devices. Ever since I “upgraded,” I’ve missed my scroll-wheel.

The playhead/timeline widget is frustrating to use and doesn’t facilitate navigation of media with any real precision.

What’s worse, the level of navigational precision decreases in proportion to the length of the audio or video file. That’s because more time gets mashed into the same 1.8” of scrubbable timeline space. This is really apparent for things like podcasts, audiobooks, movies, etc.

There are 2 problems here:
• the UI requires me to use a course-grain input method (my finger on a small display) to control a fine-grain input mechanism (timeline/playhead).
• There’s a fixed, linear mapping between input and output. In fact, they’re one and the same: input = output.

The scrollwheel doesn’t have these problems because a) the input method and interface mechanism are both course-grain, and b) input and output are only loosely coupled.

Let me explain b) a little better. The scroll-wheel is an example of an indirect, or mediated interface. I manipulate the wheel, which in turn affects the playhead’s position along the timeline. At the end of the day, this means that revolutions on the scrollwheel can translate into an increment of time that’s absolute vs. proportional to the duration of the media file.

Apple designers even inserted some really smart code into this mediation layer that let me use other cues on the scrollwheel—like velocity and acceleration—to control how fast or slow playhead moved along (like shifting gears). It works really well, and in my opinion was key to the success of the iPod early on. (Do you remember the first time you used the scollwheel on an iPod? I do.)

It’s worth pointing out that Apple could essentially make a touch-screen version of the scroll-wheel interface for iPod Touch and iPhone.

I’m not holding my breath…

David Gillis More posts by David Gillis