Quality of Experience of WebRTC based video communication

2016

Online video applications are growing in popularity and using an

increasing share of the consumer Internet traffic. Web Real-Time Communication (WebRTC) is a new technology which allows browser-to-browser

communications without any software downloads or user registration.

The focus of this report is the Quality of Experience (QoE) in the context

of WebRTC.

We have created a fully controllable testing environment, a testbed,

where we can manipulate a network to perform under various conditions

by altering the parameters packet loss rates, Mean Loss Burst Size

(MLBS), delay, jitter, Central Processing Unit (CPU), and bandwidth. A

testbed is of importance for testing of QoE services in general, and also

for application developers because they can analyze their application s

behavior in altered networks which can simulate real-world use.

We have used the WebRTC application appear.in for several different

experiments where we altered the network conditions. We have col-

lected both connection statistics and the subjective feedback from each

participant.

Firstly, we conducted a pilot study consisting of two-party conversa-

tions of 12 participants, where our main focus was on packet loss and

MLBS. After that, we conducted three-party conversations where we

tested packet loss, MLBS, delay, jitter, and CPU.

We found in our experiments that the perceived quality of a specific

packet loss rate depends also on the MLBS. Higher MLBS seems to result

in an overall worse user experience, especially impacting the audio quality

of the conversation. We also found that delay (<1 second) does not

necessarily leads to a worse user experience, while jitter quickly impacts

both audio and video quality. Finally, it seems that the CPU limitations

seem to affect only the user with the reduced CPU-usage.

The experiments show that the testbed is working as specified, and

can be used for more extensive research in the future.

Keywords - WebRTC, Quality of Experience, appear.in, testbed, pilot

study, Mean Loss Burst Size.

NTNU