Scalable ! be it audio/video, they have to fit into the foot print of the device. OS dependency and features can be made use of. Compatibility with the rendering hardware and memory/cache for parallelism. For example: if a low-end processors are used , purely integer operations can be done. In terms of video formats (YCbCr representations)

Stretching the idea of responsive web design, we need such an approach for mobile devices, given the wide range of capabilities of mobile devices. Below a certain spec, multimedia (except audio) makes no sense. Then there are issues of scaling the media to the screen size, the resolution, the bandwidth, and so on. How much does the current formats support such transformations? What will be needed further?