Playing a game on your mobile phone might be just another way to pass a little time, but it's big business. Right now, however, one facet of mobile gaming still leaves a lot to be desired: the music.
"Music has been neglected on mobile games in the past," laments Stuart Dredge, a blogger for mobile gaming site, Pocket Gamer. "In part because mobile operators placed strict limits on the file sizes of mobile games, so there wasn't enough space for decent sound alongside the graphics, animation, level designs and so on."
Michael Elman agrees. Elman is the associate director of Wave Generation, a Canadian audio production company which has worked with gaming brands including EA and Ubisoft. "Audio tends to be one of the lower priorities in the development world," says Elman. "Yet we always say that the audio people should be brought on at the earliest possible stage, so they can make an argument for how much space they're going to need."
The music element in a mobile game usually comes in one of two forms. The distinction between them is similar to the division between "real music" and polyphonic ringtones. Either the soundtrack is a master audio file like an MP3 or it comes as a synthesised MIDI file like those used in polyphonic tones. A MIDI soundtrack takes up very little space compared to a full audio recording, but it limits composers to a standard 127 sounds. And most of these are a pretty poor facsimile of the instrument they're supposed to represent.
"The one positive thing about MIDI is that, because it's programmed music it's easy to create soundtracks that are interactive with the gameplay," notes Elman. "So that the music speeds up as the levels go up."
Either way, however, composer Jim Paterson - who has created soundtracks for Scottish mobile games house Tag Games among others - argues that there is another major constraint. And that's the sound quality of mobile devices.
"While speaker quality is improving, they are better with higher frequencies than the lower ones," he says. "Composers try to compensate to some degree by boosting the bass."
Of course, the very nature of gaming on the move is itself a limiting factor. "A great mobile game isn't going to have 11 levels and 20 hours," says Elman.
"Instead, you'll play it for five minutes an infinite number of times. So while a console game might have 60 minutes of music, a mobile game will have five to ten minutes at the most, or maybe just one minute of music that loops."
The received wisdom until recently has been that mobile games are played in public. And that means, "the first thing people do is turn the sound off," says Dredge. "But the rise of music phones like Sony Ericsson's Walkman series means that more people are carrying headphones with their handset."
And the arrival of Apple's iPhone on the scene could mean a boost for casual gaming as well as for music-playing phones in general. "We have been talking to Apple about games [for the iPhone]" says EA Mobile senior vice president Mitch Lasky. "We see a lot of the technology that we've utilized on the iPod side being incorporated into the iPhone."
All this should encourage more attention on audio and even licensed music as used in Gameloft's Midnight Pool, which in April of 2005 was the first game to feature licensed audio in the form of Lynyrd Skynyrd's Sweet Home Alabama. (Even RealNetworks's 2006 Gorillaz game didn't feature any music from the band.)
So enjoy the bleeping, retro, soundchip-generated music of today's mobile games, because their days are numbered.
"It is quite obvious where the market's headed," says Elman. "Not only did we see the same transition on console games but also on ringtones. Audio gives the composers more flexibility and it sounds a lot better."