Towards QoE assessment of encrypted YouTube adaptive video streaming in mobile networks

Abstract

Video streaming has become one of the most prevalent mobile applications, and takes a huge portion of the traffic on mobile networks today. YouTube is one of the most popular and volume-dominant video content providers. Understanding the user perception on the quality (i.e., Quality of Experience or QoE) of YouTube video streaming services is thus paramount for the content provider as well as its content delivery network (CDN) providers. Although various video QoE assessment approaches proposed to use different Key Performance Indicators (KPIs), they are all essentially related to a common parameter: Bitrate. However, after YouTube adopted HTTPS as its adaptive video streaming method to better protect user privacy and network security, bitrate cannot be obtained anymore from encrypted video traffic via typical deep packet inspection (DPI) method. In this paper, we tackle this challenge by proposing a machine learning based bitrate estimation (MBE) approach to parse bitrate information from IP packet level measurement. For evaluating the effectiveness of MBE, we have chosen video Mean Opinion Score (vMOS) proposed by a leading telecom vendor, as the QoE assessment framework, and have conducted comprehensive experiments to study the impact of bitrate estimation accuracy on its KPIs for HTTPS YouTube video streaming service. Experimental results show that MBE is a feasible and highly effective approach to obtain in real time the bitrate information from encrypted video streaming traffic.