Mixed-Resolution HESP for More Efficient Fast Channel Switching and Packet-Loss Repair

Abstract

Low-delay live streaming applications desire fast channel switching and packet-loss repair capabilities. However, existing methods that provide these capabilities have a negative impact on the stream of steady-state users. To minimize this impact, techniques such as the High Efficiency Streaming Protocol (HESP) utilize keyframe injection. Such techniques combine compression-efficient normal streams with corresponding companion streams that are used in case of random access or packet loss. Unfortunately, because a companion stream is needed for every normal stream, the distribution cost and encoding complexity are considerable costs. Additionally, injecting a companion keyframe into a normal stream causes a bitrate spike. Therefore, this paper evaluates the impact of utilizing mixedresolution keyframe injection in the H.266/VVC standard. By providing a single companion stream for all normal streams of a bitrate ladder, the three mentioned downsides can be mitigated. We found that injecting a lower-resolution keyframe effectively reduces the bitrate spike, at the cost of only a modest quality loss. For dynamic video content, the quality impact reduces over time, and is less perceptible than traditional packet-loss repair using frame copy. In conclusion, mixed-resolution HESP can reduce the bitrate spike and computational/distribution overhead of HESP when enabling fast channel switching or packet-loss repair.

P-Frame Injection for Efficient Packet-Loss Repair in Ultra-Low-Latency Video Streaming

“…The proposed RRP-based method is different from earlier keyframe-injection methods [2], [3], [16], [17] since we inject P-frames rather than I-frames. As such, the bitrate of the injected P-frame of the proposed method can be lower than those of injected I-frames.…”

“…To reduce the bitrate spike of the I picture, mixed-resolution keyframe injection has been proposed [17]. In that approach, the resolution of the CS is reduced.…”

“…To evaluate the proposed method and compare it with the state of the art, we followed a similar approach as in related work [2], [3], [16], [17]. That is, we created a bitrate ladder of normal streams in four quality levels for a large and diverse set of 22 video sequences, using two coding standards.…”

“…Then, we evaluated the impact on the bitrate and quality when injecting RRPs from the CS into the NS. Additionally, we compare the performance with keyframe injection [2], [3], mixed-resolution keyframe injection [17], and traditional frame-copy packet-loss repair (in which the previous frame is simply copied when a frame is lost).…”

Catching the Moment With LoL$^+$ in Twitch-Like Low-Latency Live Streaming Platforms

“…4) High Efficiency Streaming Protocol (HESP): HESP has been designed to maintain sub-second latency, compared to legacy DASH and HLS [82], [158], [177]. HESP has been shown to achieve an E2E latency of as low as a few hundred milliseconds and short startup delays (i.e., fast channel changes and short seeking times).…”