This blog post is co-authored by Carl Fleischhauer, Project Manager, Digital Initiatives, Library of Congress.
People who manage audio and video files over time, do create fixity data, aka hash values or checksums, to help monitor the condition of those files in storage and when moved from one system or media to another system or media. And they often do what others also do: create fixity data for a whole file and allow their data management system to retain and compare that historic data with a fresh calculation, to see if the file has changed and, if so, to take remedial action. The NDSA Infrastructure and Standards and Practices working groups’ Checking Your Digital Content: How, What and When to Check Fixity paper summarizes these concepts. But people who produce audio and video files, and those who manage them, often also create fixity data on parts of files and sometimes that data is embedded in the file. What gives?

An increasing practice within the audiovisual community is to generate fixity values at the intra-file or part level in addition to the whole file. Archivist and technologist Dave Rice