STHVC: Spatial-Temporal Hybrid Video Compression for UAV-Assisted IoV Systems

Recent rapid advancements in intelligent vehicular systems and deep learning techniques have led to the emergence of diverse applications utilizing high-quality automotive videos in the Internet-of-Vehicles (IoV), often assisted by uncrewed aerial vehicles (UAVs). These applications aim to provide convenience and security for users. However, transmitting automotive videos with high-quality and low-bit-rate poses a challenge due to the inherent lossiness of traditional compression codecs in current UAV-assisted IoV systems, thereby affecting the performance of subsequent tasks. To address this, we propose a spatial-temporal hybrid video compression framework (STHVC), which integrates Space-Time Super-Resolution (STSR) with conventional codecs to enhance the compression efficiency on automotive videos. In our hybrid design, the encoder generates a low-frame-rate and low-resolution version of the source video, which is then compressed using a traditional codec. During the decoding stage, an effective STSR network is developed to increase both the resolution and the frame rate, and mitigate compression artifacts for automotive videos simultaneously. Additionally, we introduce a rectified intermediate flow estimation technique (RecIFE) within the proposed STSR network to address the challenge of noisy and inaccurate motions during the compression pipeline. Extensive experiments on various benchmark datasets demonstrate that our approach achieves bit-rate reductions of 29.97% compared to H.265 (slow) and 31.27% compared to H.266, while also exhibiting superior restoration performance compared to other state-of-the-art learning-based approaches.