Streamlining WebRTC and DASH for near-real-time media delivery

WebRTC is a set of W3C and IETF standards that allows real-time media delivery to users, with an end-to-end latency of under half a second. Support for WebRTC is built into all modern browsers across desktop and mobile devices, allowing for video, audio, and data streaming. The original focus of WebRTC has been videoconferencing. However, it is increasingly being used today for real-time streaming of premium content because of its ultra-low latency features. These features enable new user experiences involving user interactivity that are not easy to deliver or even possible with the traditional broadcast or streaming delivery protocols. Due to this increasing usage for premium content, the integration of WebRTC with the de facto adaptive streaming protocols such as Dynamic Adaptive Streaming over HTTP (DASH) is desirable. — This paper describes some use cases that could benefit from an integrated approach to streaming with DASH and WebRTC. These include the insertion of pre-recorded advertising into real-time streams such as sporting events, cloud gaming events, or concerts; co-watching synchronized streams with audio/video/text chat; and interactive broadcast content consisting of both live and on-demand elements. Interactivity can range from simple text-based feedback to the audience's video participation with event commentators. This paper describes the key performance indicators (KPIs) relevant to each use case. These include various measures of latency, delay, and synchronization as well as quality and adaptability to changing network conditions. Example workflows between DASH and WebRTC clients are provided and discussed, as are proposed architectures for both servers and clients.