Extron electronics SMP 111, Руководство пользователя

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SMP 111 • Reference Information 113
Multicast — A network technology for the delivery of information to a group of destinations
simultaneously. A single stream is sent from the source to a group of devices at the same
time in one transmission. Delivery is managed by network switches using the most efficient
strategy to deliver the messages over each link of the network only once, and creating
copies only when the links to the group of destinations split.
Network Address Translation (NAT) — A network protocol that allows multiple devices to
have their own, individual, private addresses, but they share one public IP address (IPv4) for
connection to the internet or other networks.
Network Time Protocol (NTP) — A protocol used for synchronizing the clocks of
computer systems over networks.
Opencast Server
—
An Opencast server is an open‑source platform to support the
management of audio and video content in the education market. Institutions can use an
Opencast server to produce, manage, and distribute lecture recordings.
Overscan — An applied "zoom" on SMPTE inputs (NTSC, PAL, 480p, 576p, 720p,1080i,
1080p) to hide closed caption/ancillary data, edge effects, or other video artifacts.
Parity (or Parity checking) — An error detection technique that tests the integrity of the
digital data being sent. Parity can be set to None, Even, or Odd.
Predictive frame (P-frame) — In video compression schemes, predictive frames follow
I ‑frames and contain data that has changed from the preceding I-frame (see page 112).
Presenter
—
A person who makes recordings using the SMP, regardless of their login role
(user or administrator).
When the
Record button is pressed in the AV Controls panel, the Start an Adhoc
Recording pop‑up window opens, where you can enter the name of the presenter in the
Presenter field. The name of the presenter is stored with the metadata for the recording,
and it appears in the Creator column of the Scheduled Events > Recording
Calendar > List View table. If recordings are uploaded from the SMP to an SCM,
Opencast, or Kaltura system, and if that presenter is a user of that publishing system, the
presenter or creator name is used to sort or tag that recording. An SCM system also uses
that name to route the recording to the appropriate person.
Pull streaming — Streaming method that allows users to search for content. Users specify
a content source and initiate a download or view the stream. The content streaming is
initiated by the end user (at the decoder rather than at the encoder).
Push streaming — A streaming method where the encoder sends content out to one
(unicast) or more (multicast) decoders using one of the transport protocols. Content
streaming is initiated at the encoder.
Quality of Service (QoS)
—
The grade of performance, such as transmission rates and
error rates, of a communications channel or system. QoS provides a level of predictability
and control beyond the best‑effort delivery that the router provides by default (best‑
effort service provides packet transmission with no assurance of reliability, delay, jitter, or
throughput).
Real-time Messaging Protocol (RTMP) — An application level protocol, owned by
Adobe, designed for transmission of audio, video, and data over TCP.
Real-time Streaming Protocol (RTSP) — A network control protocol designed for use in
audio visual and communications systems to control streaming media.
Real-time Transport Protocol (RTP) — An Internet Engineering Task Force (IETF)
standard for streaming real‑time multimedia over IP in packets.
Recording stream or streams
—
The primary encoding streams are used to create
recordings, and they can also be used for streaming. Recording streams are typically higher
resolution than Streaming streams.