- 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.
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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.
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- 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.
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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.