Using efficient video coding formats, a 2 gigabyte memory card can hold around five hours of video content with audio. Compression techniques and settings can increase the amount, but at the cost of video quality.
These formats are created by codecs, or software that codes and decodes a particular type of video or audio as the file is being accessed. Digital cameras, camcorders and cellphones that record raw video use less compressed formats, as higher levels of compression take more time to process. This makes it difficult for small, portable devices to handle both coding into efficient formats quickly and keeping up with the live recording, so less efficient formats are used. Software that converts an .avi video file to an .mkv video file can cut the size in half.