Important terms & definitions you need to know in the streaming industry
Have you ever felt lost when reading about streaming technologies? Have you ever heard of HLS, DASH, VOD, and P2P, but are not quite sure what that means? Finding your way in the jungle of the streaming environment needs some practice. But from now on, you never need to feel lost again when it gets technical: StriveCast has created a detailed streaming dictionary where you can find every information you might need when talking or reading about modern streaming technology.
Bitrate, CDN, Cache, and co. Get to know the basics!
Streaming is a well-known term. Not everyone can give a definition off the cuff, but nearly everybody has an idea of what it is all about. However, it becomes more complicated when it comes to the technical requirements of streaming. But let’s start at the very beginning.
Streaming is the transmission of video or audio files from a server to a client. The transmitted content can be streamed live or on-demand. Streaming works by storing a file on a server and having clients requesting it from that origin. The requested data is then sent to the viewer (possibly via a distribution network of servers) and is displayed in a web mask.
Bitrate is the number of bits that are conveyed or processed per unit of time (f.i. the number of bits processed in one second = bit/s). You can often see the term “bit” in combination with “Mega,” “Giga,” “Tera”: Mbps (Megabits per second), Gbps (Gigabits per second), Tgps (Terabits per second). That depends on the amount of data that is conveyed. Bitrate information is often used when talking about the quality of a video or audio transmission.
CDN (Content Delivery Network)
A Content Delivery Network (CDN) is a distribution network of different servers located worldwide to deliver data fast and efficiently over the Internet. Streaming as we know it would not work without a CDN. If data is sent to a large number of viewers or the data volume is enormous, a single server cannot meet the users’ requests. If too many users access a single source server simultaneously, it is quickly overloaded. But even without overload, longer buffering times for data transfer can occur if the origin server is placed far away from the client. A content delivery network consists of many different distribution servers that can spread the requested data worldwide and cache it. Each user receives the data from the server closest to them, and the source is offloaded.
eCDN (Enterprise Content Delivery Network)
An eCDN serves the same purpose as a CDN: to distribute data better. However, it is designed for internal corporate networks such as those within a company building. A corporate network may contain many different end-devices but has only limited bandwidth available. The eCDN helps distribute data within the corporate network so that the firewall does not get congested so that all users can still access a large amount of data. ECDNs can work in different ways, and one proven method, which StriveCast also uses, is to distribute data using P2P technology.
DRM (Digital Rights Management)
When it comes to transmitting data over the Internet, the term DRM appears often. DRM is used to protect digital content such as video and audio files, software, or even documents. Digital Rights Management is a kind of umbrella term for every method to protect your digital data, not only on the Internet. A typical DRM case is every kind of copyright, f.i., such as CDs but also streamed media, eBooks, and so on. There are numerous methods of protecting your data, depending on what kind of property should be covered.
Latency describes the time between a video stream and the start of its transmission. When talking about streaming, latency, low-latency (LL), or ultra-low-latency (ULL) is often heard. Especially with live streaming, the latency should be as low as possible to avoid spoilers, f.i., during a big sports event. How low the latency can be, depends mainly on the used infrastructure. How large is the CDN? How powerful are the distribution sources? However, it is never possible to avoid latency completely when transmitting over the internet.
A buffer is a place where data that is loaded from the Internet is stored for a short time (generally in the computer’s memory = RAM). The content is not loaded in real-time from the Internet, but mostly from the buffer where it was stored before. A part of the video is stored in advance so that the viewer can retrieve the data from the buffer. Therefore the video does not stop immediately if there is a network failure. The typical buffering in the sense of a delay in streaming occurs when the downloaded segments have already been watched, but there is no new data in the buffer (f.i. due to network congestion). The well-known buffering symbol appears and tells us that the stream is just stopping because new segments have to be loaded first.
Over the Top Content means data delivered via the Internet, but without involving the Internet service provider (ISP). Although the ISP is responsible for transmitting the data, it does not act as its initiator. Over-the-top-content is not transmitted by a typical broadcast provider but via the internet connection. OTT Content can be consumed from different devices, like smartphones, TV, laptops, etc. Typical OTT providers are Netflix, Amazon, AppleTV, Hulu, and more, watched over SmartTVs, XBOX, Playstation, etc.
VOD (Video on Demand)
Video on Demand is the meta description for interactive video platforms like Netflix, Hulu, Amazon Video, Disney+, etc. A VOD platform is characterized by providing digital content exactly at the moment when it is required. The user can choose from a digital library of content and watch the video whenever ready. Some VOD systems are running with a Top-Set-Box, others via the Internet. The first VOD provider started his business in the 90s while today, VOD is on the rise to replace regular TV broadcasters.
EVP (Enterprise Video Platform)
An Enterprise Video Platform is used for (video)communication within an organization. Via an enterprise video platform, it is possible to chat, phone, keep up to date regarding company news, and watch videos such as eLearning programs or speeches, conferences, and meetings. Enterprise video platforms often cooperate with an eCDN to ensure a stable video transmission even in corporate networks. The range of enterprise video platforms is immense. If you want to know more about how to choose the right EVP, you can find more information here.
Let's get more technical! Player Technology, Streaming Protocols, and more.
When it comes to delivering video data via the Internet, a lot is happening in the background. Decisive for streaming and any other activity that we map over the Internet, are protocols. They can be called the “language on the Internet.” There are many different web protocols, and only if two end devices can read the same, they can communicate with each other. So let’s now take a look at what is happening in the background.
HTTP = Hypertext Transfer Protocol
HTTP is virtually everybody’s darling among the Internet protocols. It is used throughout the internet, for example, when opening a web page. It mainly regulates the client’s request and the responses of the server. Since the beginning of the World Wide Web, HTTP has existed and is the foundation of the internet as we know it.
HLS = Hypertext Transfer Protocol Live Streaming
HLS is a streaming protocol developed by Apple that is based on HTTP. A streaming protocol is a standardized format for delivering multimedia content. Streaming protocols define how content is sent from one device to another and how they are reassembled into playable content. The main innovation of HLS was to provide the videos in adaptive bitrate.
Instead of using a single video file, HLS separates a video into many small parts. The video quality can be automatically adjusted if the available bandwidth is too low. In detail, if the upcoming parts have not been downloaded in high quality yet, the video quality is automatically lowered to avoid buffering times.
DASH (Dynamic Adaptive Streaming over HTTP)
DASH – short for “Dynamic Adaptive Streaming over HTTP” – is a streaming protocol that uses adaptive bitrate streaming for distributing high-quality media content via the Internet. Similar to HLS, DASH splits a large video file into many small sections. These usually are slightly shorter than the HLS standard of 10 seconds, namely only 2-4 seconds. So a fast change is possible when the internet connection gets lower or better. Dash is more modern than HLS but is not compatible with iOS devices. As DASH is entirely based on HTTP, any conventional server can be set up to serve DASH-streams.
ABR (Adaptive Bitrate)
Adaptive Bitrate Streaming focuses on delivering content to the user as efficiently as possible. This is done by producing multiple versions of the same content at different quality levels. Depending on the user’s internet connection, it is decided whether the user receives the lower quality (lower loading time) or the better quality (longer loading time). Every version gets its playlist of video chunks. They consist of many short segments of the video, which are stored as .ts. If the user’s internet connection improves or declines, the next segment can be loaded at a different quality level. This is an efficient way to avoid loading times.
WebRTC = Web Real-Time Communication
WebRTC, or Web Real-Time Communication, is a unicast streaming protocol, similar to RTMP, that has a feedback channel to adapt the video/audio stream to the network that’s carrying it. In practice, this means that the quality of the connection can be taken into account when selecting the most appropriate stream quality, i.e., it supports adjustable bit rate streaming. It is an open-source project that provides web browsers and mobile applications with real-time communication (RTC) via simple application programming interfaces (APIs). It allows audio and video communication to work inside web pages by allowing direct peer-to-peer communication, eliminating the need to install plugins or download native apps.
Peer-to-peer describes a technology that can establish computer-to-computer connections in real-time. In streaming, it is used to regulate data flows and provide relief for stressed servers and bandwidth. P2P networks enable viewers and their devices to share data with each other so that not everyone needs a connection to the origin server anymore. Instead, only a few do, and the risk of network congestion, problems with the streaming quality, or buffering times can be highly reduced.
P2P solutions can be used whenever a stream has enough viewers worldwide or at least enough viewers in a close geographic localization. A P2P software generates clusters of viewers, who can share the data with each other. Therefore, they need to use the same ISP, browser, etc. The more people are joining a stream, the higher is the probability that some of them fit the conditions for sharing. Many eCDNs use P2P solutions to create a stable, high-quality stream inside of corporate networks. If you like to learn more about how P2P CDN technology, you can get your free datasheet here.
RTMP is a protocol developed by Adobe that is able to transfer audio, video, and other files over the internet to a Flash Player. The protocol is also used for other Adobe applications. Since Flash Player is no longer the undisputed standard, RTMP areas are also slowly getting limited.
SRT (SubRip Subtitle file)
An SRT file is a text file that contains essential information about the video you want to stream. The SRT file is responsible for the subtitle, which is becoming increasingly important nowadays: Often, videos that are often played without sound when scrolling through social networks are provided with a subtitle so that the viewer can quickly recognize what the video is about, even without sound. Subtitles also play an important role in internationality, as they can be translated into countless languages. The SRT file contains the subtitle and important information about which part of the text belongs to which place in the video.
Flash vs. HTML5
In most cases, the video players we see in our everyday life on the Internet are based either on Flash or on HTML5. Which system is more suitable is a matter of taste. In the past, Flash players were often criticized for security gaps. HTML5 has been on the rise ever since and has proven itself, especially on mobile devices.
Get your free streaming term summary!
There are many foreign words in the field of live streaming. But to calm you down: There are many different technologies and innovations too, so it’s tough to keep up to date all the time. The way we can stream content over the Internet is continuously optimized and advanced. Sometimes it isn’t easy to keep the overview. That’s why we have created a short and concise summary of all the terms whose definitions you should not forget.