MPEG-SAND, specified in ISO/IEC 23009-5, defines standardized message formats for communication between server, client and network elements involved in the streaming process of MPEG-DASH. SAND-capable components are able to exchange real-time information of network and server components, as well as player behavior and performance data.
Fraunhofer FOKUS has implemented two libraries covering important parts of the SAND specification: The “SANDLibrary” provides tools for SAND metric reporting and the transport of status and PER messages. The library is implemented in JavaScript and integrates well with existing DASH players like dash.js, Shaka and hasplayer.js. The “SANDServer” is a Node.js-based SAND server to store metric reporting information in a database and handle the SAND shared resource allocation use case.
SAND metric reporting is an important tool for content providers as it enables players to provide streaming performance information like average throughput, buffer level, representation switch events and initial playout delay (QoE metrics defined in ISO/IEC 23009-1). SAND shared resource allocation allows network components to control how much bandwidth a client should use. This is useful in scenarios in which multiple DASH clients share the same network and compete for the available bandwidth (e.g. in a stadium, train or airplane).
Fraunhofer Institute for Open Communication Systems