The Beginner’s Guide to Video Encoding and Decoding

Are you new to the world of video streaming or broadcasting? Are you confused about the differences between video encoding and decoding? With so much terminology in this space, it’s easy for beginners to get confused and overwhelmed. That’s why we started the video encoding basics series of blog posts to explain in simple terms, the basic principles that underlie what we do here at Haivision.

What is Video Encoding?

There are two types of video encoding; live and file-based, and it’s important to make the distinction between them. When working with file-based video rather than live video, encoders are used to compress and reduce the size of video content so that it can take up less storage space and be easier to transfer from one part of a video production workflow to another.

Live video encoding is the process of compressing large, raw video and audio files in real-time so that they use less network bandwidth. When it comes to transporting uncompressed raw video, this can mean a colossal amount of data to send over any connection. Given the constant struggle for bandwidth efficiency, compression significantly reduces the bandwidth required, making it possible for real-time video streams or files to be easily transmitted across constrained networks such as the public internet.

Unlike file-based video, live video needs to be encoded with very low latency, well below 1 second, in order to prevent significant delays to the live broadcast. If you’re not already familiar with the term, latency is the time it takes for live video to travel from one destination to another. If you want to learn more about low latency and why it matters for video encoding, read our post What Is Low Latency.

To achieve the needed levels of compression , video encoders use video compression algorithms known as codecs such as H.264/AVC and H.265/HEVC which can reduce the raw content data by as much as 1,000 times. Many live broadcast workflows continue to rely on the older H.264/AVC codec while newer workfows, especially when broadcasting in 4K UHD formats, will use the newer more efficient H.264/HEVC codec.

What is a Video Encoder?

There are two types of video encoders – software and hardware-based.

Software encoders can be installed on standard off the shelf hardware or as virtual machines (VM) in data centers and cloud platforms. Although software can be a great option for encoding file-based video content, depending on the computer hardware they run on, they don’t offer ultra-low latency levels like dedicated hardware encoders and therefore are not always suitable for live broadcast contribution applications.

Hardware encoders are turnkey devices with dedicated processing power for low latency encoding of video streams. Whereas software encoders have to share CPU and other resources, hardware encoders can use purpose-designed microprocessing chips and can encode and stream live video with very little latency.

Hardware video encoders, like the Haivision Makito X4, are used by many of the top broadcasters in the world and by some of the most popular live sports events, including the BBC, the TCS New York City Marathon, Crossfit, MLB, and NASCAR. Haivision video encoders are also used in a wide range of industries for delivering high-quality, low latency video in many different applications including:

• Broadcast– Media and entertainment organizations use video encoding for the coverage of live sports, news, and events. Video encoders play an important role in broadcast workflows, including live video contribution, remote production (REMI), cloud production, and post production.
• Enterprise – Corporations, like technology and financial services companies use video encoders and video distribution systems to stream all-hands meetings, webcasts, company events, and other business-critical content.
• Energy and Utilities – Companies in the energy and utilities sector rely on video encoding technology to gain real-time insights into their remote assets. With secure live video feeds, control centers, field crews, and key stakeholders can monitor grid performance, check the condition of infrastructure, and coordinate recovery efforts following extreme weather events.
• Defense, Government, and Public Safety – for mission-critical Intelligence, Surveillance, and Reconnaissance (ISR) applications defense, government, and public safety teams can stream critical video captured from all types of platforms including helicopters, body cameras, and vehicles to support situational awareness and help these organizations make informed decisions and respond quickly to urgent situations.

For cases where IP network connectivity is unpredictable, mobile video encoders, also known as mobile video transmitters or field units, have cellular capabilities that enable broadcast video transmission over cellular networks like 3G, 4G, or 5G networks. Mobile video transmitters, like the Haivision Pro series, leverage cellular modems to encode and deliver broadcast-quality at low latency when internet access is limited or unavailable.

What is Video Decoding?

Essentially the opposite of live encoding, video decoding is the process of decoding or uncompressing encoded video. A video decoder converts an encoded video stream to HDMI for display on a screen or to SDI for broadcast production systems like video production switchers. Some video decoders can even support multiple incoming streams and include the ability to resync them prior to decoding to SDI. Video decoders can also decode embedded audio tracks for sound production as well as metadata for information on video formatting, time codes, subtitles, and closed captioning. For non-broadcast applications such as ISR video, metadata may also include vital KLV information.

There are numerous video streaming applications, each with their own set of criteria to consider for delivering an optimal viewing experience. The number of considerations can seem intimidating to beginners but with an understanding of the core concepts above, choosing and configuring a video encoder and decoder for live streaming doesn’t have to be a difficult process.