Compression of audio, images, and video

Digital audio, image, and video files contain several important characteristics that affect their quality, which often results in very large files. If you work with audio, images, and video, you may need to decide whether to compress the file format or not before sharing and long-term preserving the files.

File formats used for multimedia, such as Matroska, MP4, and AVI, are container formats (also called wrappers). Simply put, container formats make it easier for the user by packaging many types of data (audio, image, video, metadata, etc.) into one file, rather than having separate files for each type of data. The ZIP archive format is another example of a container format, as is the PDF.

To open container formats, programs need to use algorithms called codecs. A codec is a program that compresses and decompresses data, allowing files to be stored and transferred in smaller sizes. Some codecs preserve the file in its original state, either without compression or with lossless compression. There are also codecs that use destructive (lossy) compression. Destructive compression means that part of the information is lost when the file size is reduced.  

This means that destructive compression can degrade the quality of audio and image materials, but the degradation may not be directly noticeable to those viewing the image or listening to the recording. From a long-term perspective, however, it is recommended to create and preserve audio, image, and video files with the highest quality possible in an uncompressed format to avoid losing information that may be important. Additionally, you can always create compressed copies from an uncompressed original, but the reverse is not possible.

A factor that may limit the ability to preserve all files in an uncompressed format is the amount of available storage space. Therefore, you may need to decide which files are essential to share and preserve in an uncompressed format.