Back when I had a morning commute, I would often pop in some earbuds before hopping on the bus and rock out to one of the many tunes on my iPhone as we rode through Chinatown. The problem, of course, came when I reached my desk mid-song: Did I pause and try and find the song on my Mac's iTunes library? Or did I continue to listen through my iPhone, only to look up hours later and realize I'd drained my phone's battery when I should have switched to my desktop?
Seamless allows you to easily transition a song, podcast, or audiobook mid-play from your Mac to an iOS device, and vice versa. The Mac and iOS apps even coordinate fades on each device, bringing the volume of "Don't Stop Believin'" down on your Mac as it cranks up the volume on your iPhone. Both devices need to be on the same Wi-Fi network at the time of the transition, and, of course, each must have access to the same audio file to pull this off, but fulfill those two criteria and you've got yourself a magic trick.
It's actually surprising how well this works in practice. Seamless even recognizes iTunes Match tracks, and will start downloading a cloud-hosted song to your iPhone on its transition from your Mac. (I've used this trick on more than one occasion to add a few tracks to my iPhone's offline library for a flight or a road trip.) To see Seamless in action, you can check out the developer's demo video.
Though the Seamless apps perform the Mac-to-iOS-to-Mac transitions, they query and play tracks through iTunes on your Mac and the Music app on iOS. This means that once your transitioned song finishes playing, the respective music app will automatically shuffle or play the next song. If you're playing a song within a playlist on your Mac, and you also have that playlist on your iOS device, Seamless will even drop you off inside that playlist, ready to play the next song in the lineup. (Sadly, this doesn't work when transitioning from an iOS device to a Mac, but it's still pretty nifty.)
Even though my morning commute has now been shortened one bus ride, Seamless is still a fantastic little gem, and one I'm glad exists. I do wish there was a way to transition music from one iOS device to another--say, iPhone to iPad--but that's about as far as my complaints go. Now, if you'll excuse me, I'm going to transition Cake's "I Feel Free" over to my iPhone and go out for some lunch.
[Serenity Caldwell is an associate editor for Macworld.]