Understanding Lossy and Lossless Video Compression

File compression can provide numerous advantages to conserve storage space, bandwidth, and ultimately costs. That is especially the case when it comes to video, which is why most videos that are encoded for delivery are compressed in some form or other.

 

Just like all data compression, there are two types of compression that can be used in videos: Lossless and lossy. However before you jump the gun and assume that lossless is ‘better’, you should know that both have their part to play:

 

• Lossless video compression

If a video is losslessly compressed it will be encoded using algorithms that compress the data so that it takes up less storage space. However no data is discarded, and the original video data can be reconstructed exactly the way that it was from the compressed file.

In short lossless video compression preserves the video data perfectly while at the same time allowing it to take up less storage space. Some common

 

• Lossy video compression

Unlike lossless compression, lossy video compression will not only encode and compress the video data using algorithms – but it will also discard data that it considers redundant. Once a video has been compressed using lossy video compression, it cannot be restored to its original form.

The benefit of lossy video compression is that it can reduce the file size of videos far more significantly than lossless compression ever could.

 

In short although lossless videos may technically preserve the video quality far better, lossy videos have much smaller file sizes. That is why all videos that are encoded for delivery actually use lossy compression.

 

Most of the videos that you encounter on a day to day basis such as online streaming videos, video downloads, and even DVD or Blu-ray videos all use lossy compression. The only time that lossless compression tends to be used is for professional video production, as it enables the video to be edited more effectively and without intermediate loss of data.

 

It should be noted that repeatedly encoding videos using lossy compression is not a good idea however. Every time the video is encoded some data will be discarded, and over time it may start to visibly affect the quality. For example if you were to compress MP4 using another lossy compression over and over using Movavi Video Converter, you would see the difference.

 

All in all you should be able to see by now that neither lossless nor lossy are ‘better’ or ‘worse’. Instead they are just different types of compression that play different roles.

 

In a practical sense you will probably only ever deal with videos that use lossy compression – unless you are involved in professional video production that requires the use of lossless compression.