Although the current state-of-the-art H.264 codec has become very mature with efficient compression and low latency, the codec needs to be further customized for video chat. The parameters of a codec — frame rate, group of picture, size, quantization parameter, and resolution — need to be suited to the end system capabilities. For example, two mobile devices with resolutions x ¥ y (camera) and x1 ¥ y1 (display) in a group video chat may decide on a common shared resolution x2 ¥ y2 based on camera resolution of mobile devices rather than using the H.264 spatial scalability feature, which may involve high latency.