Video transmission system video transmission unit and methods of encoding decoding video data

摘要

A video transmission system 400 includes a plurality of video transmitters 420, 430, 440 (cameras) and a video receiver 410. The receiver includes a plurality of frame stores 412, 414, 416 for storing video images from the respective plurality of video transmitters 420, 430, 440. The transmitted images may include a camera reference indication which is checked by the receiver which will then switch to the appropriate frame store for the camera. Preferably each frame store holds the last received intra coded frame received from its corresponding camera so that, if transmission is interrupted, when that camera begins transmitting again the intra frame does not have to be re-transmitted, and only update information is sent. The receiver may be arranged to signal to a camera to start or stop transmitting, the camera may send an end marker to indicate when it has finished transmitting update information, or a camera may be set to only transmit if a significant change in the image sequence is detected. The system may be a surveillance system with a plurality of cameras transmitting back to a central control receiver.