Saving power in mobile devices.
Voice transmission and video playback are the biggest power hogs in mobile devices, but skipping some signal-processing tasks could greatly boost battery life without a huge sacrifice in quality. Media files must be decoded during playback, and if a device decoded only 80 percent of the information, it would use only 80 percent as much power. A new technique could cut power consumption even more, says Gang Qu, a computer scientist at the University of Maryland. Peculiarities in coding mean that the processing time–and power–required to decode a block of information varies. Qu and colleagues wrote an algorithm that imposes strict time limits on the decoding process; the decoder skips only the jobs that take too long. In simulations, this approach yielded an 81 percent completion rate but used only 37 percent as much power as decoding everything. Qu says blocks of information requiring longer decoding time may not always be more critical than the rest.