To reduce data transmission bandwidth and storage space, the compression of original video is a prerequisite for social multimedia content uploading and distribution. The paper proposes an efficient early detection algorithm of all-zero blocks to eliminate redundant computations in H.264/AVC video encoding. First, for DCT-like integer transforms, a general sufficient condition of early detection of all-zero blocks is given based on the sum of absolute differences of the prediction error block, which is a direct derivation of Sousa’s method. Then, by analyzing the dynamic ranges of different frequency components, we further refine the sufficient condition of early detection of all-zero blocks for DCT-like integer transforms and apply it to 4 × 4 and 8 × 8 DCT-like integer transforms in H.264/AVC. Experimental results show that the proposed algorithm for early detection of all-zero blocks outperforms Sousa’s method in complexity reduction, where computations in transform, quantization, inverse quantization and inverse transform are significantly reduced. In addition, the proposed general sufficient condition of early detection of all-zero blocks for H.264/AVC can also be easily extended to other forms of DCT-like integer transforms. As a result, better audience experience and more efficient analysis can be provided for social multimedia applications.
Bibliographical noteThe project was supported by the National Science Foundation for Distinguished Young Scholars of China (Grant No. 61325003).
- All-zero blocks
- DCT-like integer transform
- Early detection
- Video coding