Understanding the Basics of Video Compression and What it Does

If you are producing or managing videos, it is important that you understand the basics of video compression. The fact of the matter is that most videos are compressed for delivery, and you need to know what that means.

What is Video Compression?

To put it simply, video compression is a way of storing video data more efficiently so that it takes up less space. Uncompressed videos are notoriously large and may require several gigabytes of storage space per minute.

With video compression, the overall file size can be much lower than that – which makes the video more manageable and allows it to be distributed and stored more easily.


Types of Video Compression

In general there are two main types of video compression that you need to know about:

  • Lossless compression does not degrade the footage in any way and the original video data can be restored identically when it is decompressed and viewed. It is normally used as an intermediate format for professional video production that allows the video to be edited more effectively.
  • Lossy compression discards data that is considered redundant in order to reduce the file size by a more significant margin, but may affect the quality in the process. It is normally used for video delivery, and will produce videos that have more reasonable file sizes.

Most of the videos that you encounter online or from other sources are probably compressed using lossy compression, as lossless videos tend to have very large file sizes.

How Are Videos Compressed

The data in video files are compressed when they are stored using a video codec. The codec is responsible for encoding the video data using algorithms to compress it, and then decoding it again to allow it to be played.

Another factor that plays a part in the file size of the video is the video bitrate. It is the amount of data that is available for the video to use each second, and so the file size of the video is essentially its video bitrate multiplied by its duration.

Because different codecs use different compression, they may require different video bitrates. For example the H.265 (HEVC) codec generally requires about half the video bitrate of the H.264 codec for a video of the same quality.

If the video bitrate is not high enough however compression artifacts can start to appear in the video that will affect its quality.


Now that you understand video compression, you should be able to use it to your advantage if need be. For example you could compress video file using Movavi Video Converter by either converting it to a codec with better compression, or reducing its video bitrate.

At the end of the day it is up to you to determine the type of compression that you require for your video. Some videos may need to be compressed more than others to make streaming or distributing them more feasible, while you may only want to use lossless compression in other cases to avoid degrading the video quality.

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