You assume a media file will last long as a supported format? I have no more expectation that an MP3 or AVI will be supported by mainstream technologies in 20 years than being able to find a player then for the DVDs, CDs or BD discs I have today.
The major challenge that digital archivists are encountering is finding software that supports the files they have in their myriad formats and being able to convert them to newer formats fast enough to keep up with the increasing churn rate of formats. For historians this is a worrying trend. The deluge of data we think we have today, and that might otherwise enlighten our descendants about our times, is extraordinarily transient compared to the acetate, silver bromide, paper, velum, wood and ink, clay or stone that our forebears used. What remains of that can in some cases still be read thousands of years after it was laid down. All this is made worse by how frighteningly easy digital data is to delete.
The original 32 bit junkie now snorting pure 64. BT Yeehaw! 8 Mbit BT Homehub2, Wired, Wireless, VoIP, 2 Macs, 2.5 Hackintoshes, 3.5 PCs, OS X, Win XP, MCE, Vista, Ubuntu.
Rehab is for quitters