Understanding Video Compression in Simple Terms

When recording a video, there are several choices, one of those being what codec or compression you want to use. There are a couple of reasons for why these are important but from a quick look you can view it as how small or how large you want the file to be. The larger it is the more detail it can have but it comes at the tradeoff of either requiring special equipment to play or faster and larger memory to create and play it. 

So let’s go ahead and take a dive into what video compression is on a more detailed level so that we can understand how it affects your workflow. 

What Is Video Compression?

To put it simply, compression is just reducing the amount of data that is needed to have a video signal. The reason why we utilize compression is because raw uncompressed files can be extremely large depending on the codec they were recorded in. The goal when utilizing compression is to remove data that is seen as redundant or not necessary so that you can minimize the amount of visual quality loss while maximizing the reduction in size of the data. This is a very important part of creating video that can be streamed over a network or streamed to the web!

Why Compression Is Necessary

Put simply, most setups are not well equipped enough to handle uncompressed video. Uncompressed video can take up tons of bandwidth because the file sizes can be enormous.

If we take for example Apple’s 4K ProRes, you can be looking at as much as 6GB per minute of video footage. That is a ton of data to be sending over a network. As such, compression can make it possible to:

• Stream video over the internet
• Use AV-over-IP systems on 1G networks
• Store hours of footage without excessive storage costs
• Send video to multiple destinations at once

Without compression, most live streaming and networked video systems would require specialized infrastructure.

How Compression Works (Simple Explanation)

So how does it actually work? Essentially, compression will analyze changes between frames. If there are parts of an image that stay the same frame to frame it will just re-use the data instead of resending it. Of course there are tons of other ways that certain types of compression might handle it but in general this means that you’re reducing the amount of data while generally keeping a nice looking image. 

Common Compression Formats

Different compression standards have their own ideas on how to best balance quality and bandwidth. Here are some of the most common formats:

H.264
One of the most common formats for streaming and recording. It offers good quality at manageable bitrates and is widely supported.

H.265 (HEVC)
More efficient than H.264, allowing similar quality at lower bitrates. However, it may require more processing power.

MJPEG
Compresses each frame individually. Simpler but less bandwidth-efficient than modern formats.

Compression and Bitrate

You can look at different compression formats through bitrates. Bitrate is just a word to explain how much data is transmitted per second. 

So how does this apply to you? Well since bitrate tells you how much data is being used per second, you can extrapolate from that information that the higher the number is the more data is being sent and therefore a more detailed image. And that means it works the opposite way as well, the less data sent the easier it is to work with and the less bandwidth needed but you might have a lower quality image. 

What Are Compression Artifacts?

You can go too low when it comes to compression. Choosing something that has an aggressively low bitrate can cause weird artifacts to show up in your images.

Common artifacts include:

• Blocky or pixelated areas
• Blurred motion
• Loss of fine detail
• Smearing during fast movement

Final Notes

Understanding video compression is important in the modern AV landscape. These techniques allow for AVoIP to function the way it does as well as enable most video recording, editing, processing and streaming. 

So don’t be afraid to play around a little bit and find what codec or compression works best for your setup! If you need additional help we’re always here to answer questions.