Like many others you probably don’t know much about video compression – but are probably already using it or at least benefiting from its use. If you’ve watched any videos or handled any video files recently, it is more than likely that they are compressed.
Understanding a bit more about video compression can be useful however, and could even help you optimize your videos if you need to.
“What is Video Compression?”
Without getting technical, video compression is really just a way to structure the data in video files so that they take up less space. That is done through several different methods, and the process of structuring the data is known as encoding.
At a basic level video compression aims to reduce the amount of redundancy present in the video and reduce data that repeats itself. For example if the video has the same background throughout, the data can be stored so that the entire background doesn’t need to be repeated for every single frame in the video.
The video codec is the software that compresses the video and structures its data. It will encode the data in the video, and subsequently decode it for playback.
Types of Video Compression
Generally speaking there are two broad types of video compression that are very different from one another:
Lossless compression such as JPEG2000 involves compressing the video in a way that the original video can be restored completely without any loss of data. In short the video is preserved perfectly, and its data is just optimized so that it takes up less space.
Lossy compression on the other hand is aimed and reducing the file size further, and discards some data in order to do that. It retains as much of the video quality as possible, by focusing on discarding data that is deemed extraneous.
However once a video has been compressed using lossy compression the video cannot be restored to its original form.
“Is Lossless Compression ‘Better’?”
Although it may seem as though lossless compression is ‘better’, that isn’t exactly the case. While it is true that it will preserve the video quality better, it is unable to compress the video to the degree that lossy compression is able to.
In other words no amount of lossless compression will produce files of the size that lossy compression is able to produce. That is why almost all the video files you have ever encountered were probably compressed using lossy compression.
For example the most popular video format right now is MP4 with H.264. It uses the H.264 codec which is a type of lossy compression. Other formats do the same, and if you were to convert AVCHD to MP4 using Online Video Converter, you’d be converting between two formats with lossy compression.
Final Words
Simply put lossy compression is the option of choice for general everyday use due to the fact that it can create videos that have smaller file sizes. However for professional video production lossless compression (or uncompressed video) may be used to maintain its quality – and only the final video will be compressed using lossy compression.
