ISO 23009-6:2017 pdf free

ISO 23009-6:2017 pdf free.Information technology一Dynamic adaptive streaming over HTTP (DASH)
The basic mechanisms of MPEG-DASH over HTTP/1.1 can be augmented by utilizing the new features and capabilities that are provided by the more recent Internet protocols such as HTTP/2 and WebSocket; see Annex A for several illustrative use cases. While HTTP/2 and WebSocket are quite different in details, they both allow server-initiated and client-initiated transactions, data request cancelation and multiplexing of multiple data responses.
While in the case of HTTP/2 it is possible to carry DASH presentations without additional support, these new capabilities can be used to reduce the transmission delay (latency). Also, both HTTP/2 and WebSocket are designed to interoperate with existing HTTP/1.1 infrastructure, allowing for graceful fallback to HTTP/1.1 when the more recent protocol is not available.
The overall workflow of MPEG-DASH over these protocols is shown in Figure 1. The client and server first initiate a media channel, where the server can actively push data to the other (enabled by HTTP/2 server push or WebSocket messaging). The media channel may be established via the HTTP/1.1 protocol upgrade mechanism or by some other means. After the connection is established, the DASH client requests the media or the MPD from the server, with a URI and a push strategy. This strategy informs the server about how the client would like media delivery to occur (initiated by the server or initiated by the client). Once the server receives the request, it responds with the requested data and initializes the push cycle as defined in the push strategy. Annex B shows a typical end-to-end video streaming system over HTTP/2 that can benefit from signalling and messages defined in this document.
Figure 1 shows an example DASH session wherein the client requests the MPD first and then the media segments with a push strategy. Initialization data are pushed in response to a push strategy associated to the MPD request. After receiving the requested MPD, the client starts requesting video segments from the server with the respective DASH segment URL and a segment push strategy. Then, the server responds with the requested video segment, followed by the push cycles as indicated by the segment push strategy. Typically, the client starts playing back the video after a minimum amount of data is received and then the aforementioned process repeats until the end of the media streaming session.ISO 23009-6 pdf download.