A NEW OPTIMIZED IMPLEMENTATION OF A FAST INTRA PREDICTION MODE DECISION ALGORITHM FOR HEVC STANDARD

New and stronger video compression standard was developed during the last years, called H.265/HEVC (High Efficiency Video Coding). This standard has undergone several improvements compared to H.264/AVC (Advanced Video Coding). In intra prediction block, 33 directional intra prediction modes were included in H.265 to have an efficient coding instead of 8 modes that were used in H.264 in addition to planar and DC modes, which has generated computational complexities in the new standard. Therefore one of the most issues for embedded implementation of HEVC is time reduction of the encoding process. In this paper, an embedded implementation of a fast intra prediction algorithm is performed on ARM processors under the embedded Linux Operating System. Experimental results included the comparison between the original HM16.7 and the proposed algorithm show that the encoding time was reduced by an average of 61.5% with an increase of 1.19 in the bit rate and a small degradation in the PSNR of 0.05%.

A Fast Intra Prediction Algorithm Based on WMSE for 360-Degree Video

With the increased demand for virtual reality, 360-degree video coding becomes challenging. A 360-degree video should be projected as a planar video before encoding, but this process causes distortion whose degree depends on the latitude. Traditional coding algorithms cannot effectively adapt to this feature. In this study, a fast intra prediction algorithm based on WMSE for 360-degree video is proposed. The similarity between the mother block and child blocks can reflect whether the mother block needs to be divided. Spherical weights are introduced in WMSE, and the similarity expressed by WMSE can distinguish the video of different latitude, which is consistent with the weight characteristics of ERP projection. Experimental results show that the proposed algorithm achieves 32% time reduction, with only 0.29% luma Bjontegaard delta rate (BD-rate) increase on average. The proposed algorithm provides a more effective solution to reduce the coding complexity of 360-degree video.