Experimental study of QoE improvements towards adaptive HD video streaming using flexible dual TCP-UDP streaming protocol

The Flexible Dual TCP-UDP Streaming Protocol (FDSP) combines the reliability of TCP with the low latency of UDP, thus providing transport layer improvements towards maintaining high QoE of multi-bitrate videos in adaptive streaming. FDSP delivers the more critical parts of the video data via TCP and the rest via UDP. FDSP also uses Bitstream Prioritization (BP), a sliding scale that determines the proportion of video data that is sent using TCP. BP can be adjusted according to the level of network congestion. FDSP-based streaming reduces total rebuffering time by over 90%, and rebuffering instances by 50% in many cases compared to TCP-based streaming. At the same time, packet loss reduces by over 75% for most BP levels compared to UDP-based streaming. In addition, FDSP-based streaming is potentially more suitable for adaptive streaming compared to the state-of-the-art TCP-based HTTP Adaptive Streaming (HAS), which is often plagued by high latency and high bandwidth requirements. In contrast, FDSP requires significantly less bandwidth than TCP in congested networks while exhibiting more stable client buffers.