There is disclosed a video encoder comprising a base layer encoder and an enhancement layer encoder. The base layer encoder receives an input stream of video frames and generates compressed base layer video data suitable for transmission to a streaming video receiver. The enhancement layer encoder receives the input stream of video frames and a decoded version of the compressed base layer video data and generates enhancement layer video data associated with the compressed base layer video data and suitable for transmission to the streaming video receiver. The video encoder also comprises a controller associated with the enhancement layer circuitry for receiving a quantization parameter associated with the base layer video data and determining therefrom at least one all-zero bit plane associated with at least one block of the enhancement layer video data. The controller is capable of causing the enhancement layer circuitry not to transmit the at least one all-zero bit plane to the streaming video receiver.