LOT codec for Hi-Vision Digital VTRs has been developed. The codec compresses the Hi-Vision signals by the intrafield 2-dimensional LOT (Lapped Orthogonal Transform) and the mutilple pairs of the scaler quantizer and the VLC generator. The data rate per field is kept constant by the new data rate control algorithm minimizing the objective function considering the picure quality and the constraints on the target data rate. The results of the experiments by the computer simulations and the subjective assessment tests are described by comparing with the DCT codec using the proposed data rate control.
