Energy-aware QoS adaptation for streaming video based on MPEG-7

We propose a QoS adaptation method for streaming video playback for portable computing devices where the playback quality of each video fragment is automatically adjusted from the remaining battery amount, desirable playback duration and the user's preference for each fragment. In our method, we assume that video segments (or shots) are classified into some predefined categories. Each user specifies the relative importance among categories and preferred video properties, such as proportion between motion speed and vividness for each category. From this information, playback quality and the properties of each category are determined so that the video playback can last for the specified duration within the battery amount. We have implemented a video streaming system consisting of a transcoder for PCs and a video player for PDAs.