Computer software is constantly evolving. There's no guarantee that a particular file format currently in use will remain accessible in 10 years. Archivists assess several factors to select formats that seem most likely to remain sustainable over time, including whether the format is open source or proprietary, compression, and user support. See Important Digital Archiving Concepts on the main page for more information.
This section includes file format recommendations based on current expectations for long-term accessibility. Use stable file formats that are best suited to how you use your digital files. Of course, the best time to do this is as you create new files.
The preferred preservation formats for high quality audio are wav (uncompressed) or flac (compressed but without loss in quality).
For everyday use and lower (compressed) file size, aac is considered better quality than mp3, which is widely used for streaming and mobile devices.
To hear what audio data gets eliminated by mp3 compression, check out Ghost in the MP3.
The Preserve This Podcast team presents illustrated guidance on organizing, backing up, and creating metadata for your podcast files (and audio content in general), with links to interactive exercises.
Preservation container formats for digital video (which also contains audio files) include avi and mov (Quicktime).
For lower file sizes, mp4 is a popular and widely supported container format for the H.264 video compression codec and aac audio codec.
This DC Punk Archive/Memory Lab zine covers the preservation of analog (physical) home video and film formats, with tips for digitizing and preserving digital video.