Video Streaming Glossary

Video Streaming Glossary

We know that between encoders and RTMP’s, the lingo of streaming can get a little confusing. Luckily we’ve broken down all the streaming terms you need to know from A to Z (or W for workflow, as the case may be). Glossary courtesy of Livestream.

 

Akamai: The world’s largest CDN (Content Delivery Network) with 90,000+ servers all over the world.

Anti-Lag: A tool in Livestream Producer and Livestream Studio that can be triggered when the encoder’s local Internet connection becomes slow. When enabled, it will build a cache of frames until it reaches a certain amount, and then clear that cache. This is in attempt to keep viewers at the most up-to-date live content. Having this feature disabled while Internet connection slows down will cause buffering and an endless cache of frames growing. While this will prevent choppy VODs, live viewers will be significantly behind the live content.

Aspect Ratio: The proportional relationship between an image’s or player’s width and its height. The standards for broadcast are 4:3 and 16:9. HD video is natively 16:9, which is what we recommend. 4:3 is typical for SD video.

Audio Mixer: A controller that takes in and combines various audio sources and allows the user to route each audio signal to a proper output and adjust each source’s levels. Can also be referred to as a sound mixer, mixing desk, or simply a mixer.

Bandwidth: Typically measured in bitrates, bandwidth refers to the amount of data that can be transferred from one location to another in a given amount of time.

Bitrate: The speed at which data is transferred over the Internet. The data is measured in bits, not to be confused with bytes.

Kilo-bit per second (Kbps): A unit of data transfer rate equal to 1,000 bits per second.

Mega-bit per second (Mbps): A unit of data transfer rate equal to 1,000,000 bits per seconds or 1,000 Kbps.

Blackmagic Design: Blackmagic Design is a company that creates several recording and encoding products that are compatible with Livestream’s technology including several capture cards and devices.

Bonding: Bonding allows you to combine multiple internet sources (ethernet, wifi, and/or 4G cellular data) to establish a redundant connection for your stream. It is a feature of the Livestream Studio software.

Broadcaster Pro: An ideal solution for single-camera streams, the Broadcaster Pro can stream any HDMI camera directly without the need for a computer. All you need is an event page to stream to and an Internet connection via Ethernet, WiFi, or 4G.

Buffering: Before a video can play, a certain amount of pre-loading data must be downloaded to stream.

Capture Cards/Devices: Hardware devices that convert the analog video signal coming from a camera into a digital format that a computer can read and understand. Different models connect to a computer through different means (PCIe, USB, Thunderbolt) and support different video signals (SDI, HDMI, Component, etc.).

Central Processing Unit (CPU): The brains of the computer that carries out instructions given by a computer program by performing calculations and operations.

Chroma Key: A special effects technique where a block of color (often blue or green) in a video frame is replaced by another color or image. The most common use is during the weather forecast segment of a news program. Chroma keying allows the forecaster to stand in front of a computer-generated map, when they are actually standing in front of a large green wall.

Content Delivery Network (CDN): A distribution system on the Internet that accelerates the delivery of Web pages, audio, video, and other Internet-based content to users around the world.

Dedicated Bandwidth: Bandwidth that is reserved to a single purpose on a network. With a dedicated connection, it is possible to guarantee a certain amount of bandwidth for the duration of a stream. For example: A Network Administrator at a trade show, for a fee, is able to allocate a specific amount of bandwidth on a network to an exhibitor for the duration of a show. Dedicated bandwidth is always recommended for livestreaming and is required for events produced by the Livestream Production team.

Download Speed: The rate that data can be transferred from the Internet to a user’s computer or device. This is key for users looking to watch a stream.

Embedded Audio: The audio signal is sent to the output source through the video signal. This workflow is recommended to avoid audio/video sync issues. For example, a microphone is plugged into a camera, then a single HDMI cable connected to the camera carries both the video and the microphone’s audio to an encoder simultaneously. The opposite would be the microphone being plugged into the encoder directly, separate from the camera.

Embedded Video: A video player that can be seen on one website but is hosted on another website through HTML embed code.

Encoding (video): Encoding is the process of converting from a video source to a format that can be streamed over the Internet. Example: Procaster/Producer will convert a video source to H.264/AAC to be displayed on a Livestream player or mobile device.

Firewall: A security system that is designed to block unauthorized access while permitting authorized communications. This can cause issues when streaming if not configured properly. Livestream Studio, Producer, and Procaster use ports TCP 1935, 80, and 443.

Flash Player: A legacy software made by Adobe for viewing multimedia, Rich Internet Applications, and streaming video and audio, on a computer web browser. Capable of playing video in a variety of supported formats (most commonly H.264, H.263, VP6, VP7).

Geo-Blocking: The ability to restrict access based on the location of the individual attempting to see the content. This is typically determined by IP address.

Graphics: Logos, lower thirds, and text featured on screen during a stream or on-demand video.

HDMI (High Definition Multimedia Interface): An audio/video interface for transferring video and audio data to and from HDMI-compliant source devices (cameras, receivers, etc.). A common standard for connecting HD devices at the consumer level.

HD Resolutions: High Definition video resolution, which contains more pixels than Standard Definition.

HD SDI: High Definition Serial Digital Interface. It’s a video interface standard that allows for the transmission of high definition video over coaxial cable at faster speeds than other HD options, thus is recommended when longer cable runs are required.

Internet Solutions:

4G and LTE: A Mobile internet connection uses a 3G or 4G modem to transmit data and is part of a shared network. Since connection speed plays a large part in the success of a livestream, a mobile internet connection is not recommended. Networks with faster upload speeds than 3G as a result of limited user activity, improved technology, and reliability.

Wi-Fi: A wireless connection that allows multiple devices to communicate on a shared network without cables. Should be used for streaming only in extreme cases when no other option is available.

Wired: A hard-wired connection that is established using an Ethernet cable. The cable is connected by the Ethernet port on a computer into an Ethernet outlet on a switcher/router or modem. A wired connection does not always mean the connection is dedicated. Other devices can pull bandwidth from a router that the Ethernet cable is connected to. For streaming, a wired connection is considered to be more reliable and is always recommended.

Non-Dedicated Bandwidth: Bandwidth that is shared over multiple devices on a single network can be wireless or wired; with no restrictions on what devices are in use and how much bandwidth they are using causing a sometimes-unstable connection. For example: A WiFi network located in an airport terminal that is open to the public with multiple devices sharing bandwidth on the same network.

ISO Recording: Abbreviation of ‘Isolated Recording.’ A recording of a single a camera source during a multi-camera production. Typically, multiple ISO recordings are done simultaneously and are edited together in post-production.

Key Frame Interval: A keyframe is a full frame of an image that provides a reference point within a video. They are typically used to detect changes in the video, such as movement of a talking head. The interval is how often keyframes are set within the video, which is configured in the encoder. If you are expecting lots of movement in your video, it’s best to have a shorter key frame interval, which can be data intensive and thus create a larger sized video.

Latency: The amount of time it takes for data to reach one point to another (e.g. the video from the event to be seen by the viewer). Synonymous with ‘lag’ and ‘delay.’ In livestreaming, lower latency is ideal. Livestream streams have about a 20-30 second latency to allow and facilitate DVR.

Live Video Output: A physical output coming from your camera or switcher that allows your video source(s) to be seen in another source like a projector or monitor.

Lower Thirds: A lower third is a graphic overlay placed in the lower area of the screen, but not taking up the entire area. Lower thirds are used to identify speakers, places, or events on screen not previously identified in the context of the video.

Media Bins: A module in video software where a producer or editor can import and organize their pre-recorded video files

Open Broadcasting Software: Open Broadcaster Software is free and open source software for video recording and live streaming.

Password Protection: Restricting access to streaming content via a password that is given out only to those who should see it.

Picture in Picture (PiP): The ability to see multiple video sources simultaneously.

Ping: Tests the reachability of an IP network or a server. It measures the round-trip time for messages sent from the originating host to a destination computer and then back to the source, typically in milliseconds.

RTMP (Realtime Messaging Protocol): A protocol used for streaming audio, video and data over the Internet between a Flash player and a server. Commonly used by Adobe Flash Media Encoder, NewTek Tricaster, and Telestream Wirecast.

RTP (Realtime Transport Protocol): A network protocol for delivering audio and video over IP networks. Commonly used with video teleconference systems and web-based push-to-talk features.

RTSP (Realtime Streaming Protocol): A commonly used streaming protocol designed for entertainment and communications systems to control streaming media servers. Clients of media servers issue VCR-style commands, such as play, record and pause to facilitate real-time control of the media streaming from the server to a client (Video On Demand) or from a client to the server (Voice Recording).

Satellite Uplink/Downlink: When you do not have access to a dedicated 4G or Ethernet network, for example in a broadcast truck, a broadcaster can beam the livestream signal to a satellite and route it back to an office or dedicated line for encoding.

SD (Standard Definition) Resolutions: Any video resolution below 1280×720 is considered SD. Common SD resolutions include 1024×576 pixels and 720×480 pixels.

Switcher: Traditionally a large device that is used to select and switch between several different video sources, control graphics overlays, and perform keying operations and general color signals. In recent years, switchers have become available as software installed on PC’s like Livestream Studio, Newtek Tricaster, etc.

Transcoding: The process of converting data from one form of coded representation to another. The process by which video files are converted to a reduced bit rate while still maintaining the original video format. This enables users to fit specific media into a much smaller storage space or deliver video files more efficiently using reduced bandwidth.

Transmission Control Protocol (TCP): TCP is a communications protocol which enables two hosts to establish a connection and exchange streams of data. Guarantees not only the delivery of data but also that packets will be delivered in the same order in which they were sent.

Upload Speed: The rate that data can be transferred from a user’s computer or device to the Internet. This is key for users looking to broadcast an event.

User Datagram Protocol (UDP): A communications protocol used primarily for establishing low latency and lost-tolerating connections between applications on the Internet. Ideal protocol for network applications in which perceived latency is critical such as streaming or gaming.

Video/Audio Compression:

H.264: Is a standard for video compression, and is currently one of the most commonly used formats for the recording, compression, and distribution of high definition video.

AAC: Advanced Audio Coding is the default or standard audio format across all media platforms, including YouTube, iPhone, iPod, and iPad.

Video on Demand (VOD): The ability for viewers to watch or listen to content when they choose to rather than having to watch at a specific time.

WebRTC: WebRTC enables voice and video calling directly inside a web browser without a plugin or installation via a JavaScript code run from your HTML page.

White Labeling: The practice of a product or service being provided by one company but rebranded by another to make it appear as if the latter made it.

Workflow: A sequence of equipment or processes through which a piece of work passes from initiation to completion. In video production, it typically refers to the process in which your video and audio reach your audience: what camera, cables, capture device, encoding software/hardware, Internet connection, etc. is being used.

Glossary courtesy of Livestream.

 

 

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AVFX is an audiovisual staging company located in Boston, MA, offering audio, video and lighting services to meeting planners, exhibit builders and special event producers in New England and across the US.