QoE matters more than QoS: Why people stop watching cat videos

With the proliferation of online video, measuring quality of experience (QoE) has become a pivotal aspect for the analysis of today's over-the-top (OTT) video streaming. To monitor video QoE, we introduce YouSlow that can detect various playback events (e.g., start-up latency, rebufferings and bitrate changes) from video players while a video is being played. Using YouSlow, we have collected more than 400,000 YouTube views from more than 100 countries. We measured the impact of these playback events on video abandonment and found that rebufferings incur abandonment rates six times higher than start-up latency, mostly caused by pre-roll ads. A single rebuffering event has three times the impact of a bitrate change. Even increasing the bitrate can raise abandonment rates by a factor of four compared to keeping the bitrate constant.