PVI VECASTER PRO Series, Manual

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VECASTER SERIES MANUAL Pro Video instruments
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4. HLS — HTTP Live Streaming
● HTTP-based adaptive bitrate streaming communications protocol.
● Works by breaking the overall stream into a sequence of small HTTP-based file downloads, each download loading
one short chunk of an overall potentially unbounded transport stream. A list of available streams, encoded at
different bit rates, is sent to the client using an extended M3U playlist.
● Based on standard HTTP transactions, HTTP Live Streaming can traverse any firewall or proxy server that lets
through standard HTTP traffic, unlike UDP-based protocols
● HTTP Live Streaming uses a conventional web server to distribute audiovisual content and requires specific
software to fit into the proper format transmission in real time.
● HTTP Live Streaming provides mechanisms for players to adapt to unreliable network conditions without causing
user-visible playback stalling. For example, on an unreliable wireless network, HLS allows the player to use a lower
quality video, thus reducing bandwidth usage. HLS videos can be made highly available by providing multiple
servers for the same video, allowing the player to swap seamlessly if one of the servers fails.
5. UDP — User Datagram Protocol
● With UDP, computer applications can send messages, in this case referred to as datagrams, to other hosts on an
Internet Protocol (IP) network. Prior communications are not required in order to set up communication channels
or data paths.
● UDP is suitable for purposes where error checking and correction are either not necessary or are performed in the
application. UDP avoids the overhead of such processing in the protocol stack. Time-sensitive applications often
use UDP because dropping packets is preferable to waiting for packets delayed due to retransmission, which may
not be an option in a real-time system.
● Suitable for very large numbers of clients, such as in streaming media applications such as IPTV.
● Because it supports multicast it is suitable for broadcast information such as in many kinds of service discovery and
shared information.
6. RTSP — Real Time Streaming Protocol