A Compressed View of Video Compression

A Compressed View of Video Compression. Richard Wright. Preservation Guide. 22 June 2015.
   Digital audio and digitised film can also be compressed, but there are particular issues. The basic principle is that audio and video signals carry information, though the efficiency may vary. "The data rate of the sequence of number representing a signal can be much higher than the rate of information carried by the signal. Because high data rates are always a problem, technology seeks methods to carry the information in concise ways." The video signal has been altered in order to squeeze it into limited bandwidth. Redundant data  may be sent in the signal to improve the odds that the information will be transmitted. It is important to know what matters and what can be discarded. With preservation, "a key issue is management: knowing what you’re dealing with, having a strategy, monitoring the strategy, keeping on top of things so loss is prevented." Basic principles of preservation also apply to compression:

• Keep the original
• Keep the best
• Do no harm

 There are best practices in dealing with compressed materials, and in migrating compressed versions to new compressed versions. His estimate is that with storage costs decreasing "there will be no economic incentive for such a cascade of compressions." "The next migration will dispense with the issue by migrating away from compressed to lovely, stable uncompressed video."

Digital Preservation Matters.