DUAL-C: Building a "soft error efficient"on-the-fly compression mechanism for raw video data at edge devices

Nowadays, various edge applications play an increasingly important role in our life, in which video data accounts for a dominant portion of the data traffic. Although standard compression methods, such as H.264 and MPEG4, can considerably reduce the wireless bandwidth for transmission energy savings of edge devices, the large volume of raw video streaming data is still buffered in edge device video buffer, constituting non-negligible energy consumption. Beyond energy issues, edge video data has been increasingly applied in safety-critical scenarios, where reliability has also become a critical concern. Unlike the controlled accuracy sacrifice of the lossy compression mechanism, the high information content per bit may render compressed data more sensitive to random transient faults attacking (i.e., soft errors), thereby inducing severe safety hazards in some video processing tasks (e.g., autonomous vehicle collision). Thus, in this paper, we propose a "soft error efficient'' on-the-fly compression mechanism named DUAL-C to achieve energy savings in edge device video buffer while maintaining data reliability. Firstly, observing the duplicate feature of upper bits and approximable characteristic of lower bits within the camera sensors generated streaming raw pixel blocks, we design two compressing techniques: DU-C extracts the common duplicate upper-bits while AL-C merely stores one representative approximate lower-bits for all pixels within a block. By combining DU-C and AL-C with the Sampling-based Approximation paradigm (SA), DUAL-C achieves the overall energy consumption reduction of the video buffer by 71.31%. Secondly, to avoid the reliability "dark side"introduced by compression, we conduct a comprehensive error resilience analysis of compressed data and merely harden the error-critical control bits and common upper bits with ECC. Evaluation results show that DUAL-C compressed data exhibits even better error robustness than its uncompressed counterpart with negligible protection overhead.