Zero-Quantized Inter DCT Coefficient Prediction for Real-Time Video Coding

Several algorithms were proposed to predict the zero-quantized DCT coefficients and reduce the computational complexity of transform and quantization. It is observed that these prediction algorithms achieve good performance for all-zero-quantized DCT blocks. However, the efficiency is much lower for non-all-zero-quantized DCT blocks. This paper proposes an algorithm to improve the prediction efficiency for non-all-zero-quantized DCT blocks. The proposed method extends the prediction to 1-D transforms by developing new Gaussian distribution based thresholds for 1-D transformation. Moreover, the proposed algorithm can perform the prediction on 1-D transforms in both the pixel domain and the transform domain. The prediction for the first stage of 1-D transforms is performed in the pixel domain. However, the second stage of 1-D transforms is performed in the 1-D DCT domain. Because after the first stage of 1-D transforms most energy is concentrated to a few low frequency 1-D DCT coefficients, many transforms in the second stage are skipped. Furthermore, the method fits well the traditional row and column transform structure, and it is more implementation friendly. Simulation results show that the proposed model reduces the complexity of transform and quantization more efficiently than competing techniques. In addition, it is shown that the overall video quality achieved by the proposed algorithm is comparable to the references.