ETPS: Efficient Two-Pass Encoding Scheme for Adaptive Live Streaming

In two-pass encoding, also known as multi-pass encoding, the input video content is analyzed in the first-pass to help the second-pass encoding utilize better encoding decisions and improve overall compression efficiency. In live streaming applications, a single-pass encoding scheme is mainly used to avoid the additional first-pass encoding run-time to analyze the complexity of every video content. This paper introduces an Efficient low-latency Two-Pass encoding Scheme (ETPS) for live video streaming applications. In this scheme, Discrete Cosine Transform (DCT)-energy-based low-complexity spatial and temporal features for every video segment are extracted in the first-pass to predict each target bitrate’s optimal constant rate factor (CRF) for the second-pass constrained variable bitrate (cVBR) encoding. Experimental results show that, on average, ETPS compared to a traditional two-pass average bitrate encoding scheme yields encoding time savings of 43.78% without any noticeable drop in compression efficiency. Additionally, compared to a single-pass constant bitrate (CBR) encoding, it yields bitrate savings of 10.89% and 8.60% to maintain the same PSNR and VMAF, respectively.