Error Concealment Capacity Analysis of Standard Video Encoders for Real-Time Immersive Video Streaming from UAVs

In this work, we analyze the error concealment capacity of various video codecs, for real-time streaming of 360° videos from a unmanned aerial vehicle (UAV) to ground based user. For this study, we evaluate the performance of various recent encoders in ISO/IEC and ITU-T standards: high-efficiency video coding (HEVC)/H.265 and advanced video coding (AVC)/H.264, including both their software and hardware implementations. We also consider the AOMedia video 1 (AV1) encoder from alliance for open media (AOM) formats. We benchmark the codecs by examining the video freezing time for each codec, i.e., the number of dropped frames, for transmission of 360° videos over an air-to-ground (A2G) wireless channel without any forward error correction. Interestingly, our results show that while AV1 achieves the best quality in terms of peak signal-to-noise ratio (PSNR), it exhibits worst error concealment capacity, resulting in the longest video freezing time among all the encoders. Further, we observe that the AVC yields the most robust performance against the impairments induced by the wireless channel. To present a complete picture, we also benchmark the codecs with respect to coding efficiency, and encoding/decoding latency at multiple bit-rates. In this study, we find that the AVC yields lowest latency for both software and hardware implementations. However, considering video quality, the hardware-based implementation of HEVC provides the best trade-off among all the parameters. Overall, our results provide novel and interesting insights on the choice of encoders for real-time 360° video transmission from a UAV to ground user.