HEVC transforms with reduced elements bit depth

Abstract

High-efficiency video coding (HEVC) is based on integer discrete cosine transforms (DCTs) of size 4 × 4, 8 × 8, 16 × 16 and 32 × 32 whose elements are coded on 8 bits. However, the algorithm requires that the output length at each processing stage should never exceed 16 bits. The conventional solution is the truncation of the least significant bits which leads to erroneous results and a waste of resources. In this Letter, different DCT kernels with reduced elements length are proposed. They are evaluated for compression efficiency and hardware implementation competence. An implementation on the Xilinx FPGA virtex-6 circuit has given a maximal operating frequency increase of 4.81 and 93.41% for the DCT-II 4 × 4 and the discrete sine transform, while reducing the energy consumption by 10.64 and 30.77% at 100 MHz, respectively. Using the HM 16.3 HEVC model and video sequences of different resolutions, the results show a quality degradation of 0.01 dB for a bit rate increase of 0.19% compared to the reference cores.

An Efficient Low Complexity Region-of-Interest Detection for Video Coding in Wireless Visual Surveillance

“…From Figure (7) we can deduce that the algorithm is efficient in saving a substantial amount of processing and transmission power. The saving achieves more than 90% of the energy most of the time.…”

“…Figure (7) illustrates the per-frame energy consumption of the proposed method compared to ROI-based compression methods, namely, [30] referred to as EMP '22, [16] referred to as SSD'22 and the forward baseline compression (MJPEG). Since the algorithm is applied to each frame, constant energy is spent for each frame, while the total energy curves oscillate based on the number of blocks to compress.…”

“…This paradigm has been put forth as a substitute for the conventional compress-then-analyze (CTA) paradigm, which compresses the entire captured video before transmitting it to be processed further when it is received. The CTA paradigm typically employs highly complex video coding standards [4], such as MJPEG [5], H264 [6], and HEVC [7]. As a result, the ATC can streamline this process and enable video coding within limited resources devices [2].…”