• Video Compression is the process of encoding a video file in such a way that it consumes less space than the original file and is easier to transmit over the network/Internet.
  • It is a type of compression technique that reduces the size of video file formats by eliminating redundant and non-functional data from the original video file.
Why do we need video compression?
  • Video is transmitted as electrical signals, as we’ve seen here. These signals usually move around via air (radio waves, microwaves, etc.) or via cables.
  • A cable has a limited diameter and limit of a broadcast system is called its bandwidth.
  • In the case of wireless transmission, where only a limited number of frequencies can travel in spectrum. The governments of each country limit the spectrum within their territory.
  • Video compression allows the efficient utilization of bandwidth by reducing file sizes.
     Two different kinds of compression: 
     - Lossy compression:
  • Lossy compression means that the compressed file has less data in it than the original file.
  • Images and sounds that repeat throughout the video might be removed to effectively cut out parts of the video that seen as unneeded.
  • In some cases, this translates to lower quality files because information has been "lost," hence the name.
  • Lossy compression methods don't make pixel-by-pixel copies of the source at all.
  • They work in several different ways, but the general result is the same.
  •  It makes up for the loss in quality by producing comparatively small files. 
  • Most video files uploaded to the internet uses lossy compression to keep the file size small while delivering a relatively high-quality product.
  • For example, DVDs are compressed using the MPEG-2 format, which can make files 15 to 30 times smaller, but viewers still tend to perceive DVDs as having high-quality pictures.
     
     - Lossless compression:
  • Lossless Compression is a class of data compression algorithms that allows the original data to be perfectly reconstructed from the compressed data.
  • The latest standard in video compressing is High Efficiency Video Coding(HEVC). This is said to double the amount of data compressed while retaining the same level of video quality.
  • Over all, lossless compression is best for every stage of the editing process from capture to edits, but lossy compression formats are currently the best way to deliver high-quality video to your portable media player or to YouTube.
Advantages:
  • Video file requires less storage space.
  • File transferring is faster.
  • Order of bytes is independent.
  • Reading and writing the video files is faster.
Disadvantages:
  • Complicated work process.
  • Errors can occur during compression, transfer and streaming.