Ericsson SVP 2000, Reference Manual, Page: 17 / 196

Introduction
1.3 SVP 2000 Video Processor Basics
1.3.1 Key System Elements
The key elements of the DASH system are:

the Encoder
- the files created and stored
- the manifest file is compiled
- the file playout

the Decoder
- rebuild of the transport stream
- control of the rate of media transfer
The video comes into the Encoder, either via SDI or as a Transport Stream over a
GigE connector, it creates up to five profiles and a manifest file. Each video profile is
DASH segmented as a file.
The bit rates for each segmented file available for transmission are recorded in the
manifest file.
The Decoder monitors the receive data rate (measured time for known file size).
Depending on the request from the Decoder, the Encoder transmits appropriately
encoded file segments.
The stream of file chunks fetched by the Decoder consists of different sizes i.e. bit
rates. The incoming files are then collated by the decoder and re-encoded into a
video that is sent out either as a transport stream or over the SDI. The bit rate of the
encoded video can also be defined at the Decoder
1.3.2 Video Profiles
The video stream input is fed into the Encoder which creates a number of different
bit rate profiles of the same video. At the Decoder, the lowest bit rate profile is pulled
and the data transfer speed over the network is checked. If the data transfer is
quicker than the playout time of the video, the Decoder requests a higher bit rate for
the segment. If this gets through quicker than the playout time, the Decoder
requests an even higher rate profile. Eventually, a requested profile will fail to get
though in the playout time. At this point, the Decoder requests the lower rate.
EN/LZT 790 0046/1 R1A 1-9