Method for detecting all-zero DCT coefficients ahead of discrete cosine transformation and quantisation

The authors present a new algorithm for detecting all-zero DCT coefficient blocks before discrete cosine transformation and quantisation in very low bit rate video coding. The proposed algorithm uses the sum of absolute difference (SAD) of each motion compensation block as the criteria. Because the SAD can be obtained after motion estimation, no additional computation is required. Results show that the proposed algorithm can be used to reduce the amount of computation significantly without sacrificing video coding quality