Hi everyone,
Our digitization vendor currently provides “preservation” and “access” WAV files that DROID and Siegfried recognize as PRONOM
fmt/704. By default, Archivematica does not recognize fmt/704 as a preservation format, and it does not have a normalize for preservation rule. I was curious how Archivematica and ffmpeg would handle these files if I decided to normalize them for preservation, so I set up a local rule for fmt/704 in our test environment.
ffmpeg appears to take the "preservation" WAV files and normalize them into
fmt/143 files. And it normalized the "access" WAV files into
fmt/141 files. fmt/143 is not recognized as a preservation format, so I don't want that to be the result of any effort to normalize fmt/704 files for preservation. fmt/141 *is* considered a preservation format, but I see in PRONOM that it has been superseded by fmt/141 and fmt/142.
This all leads me to a few questions I am hoping list members can help answer:
- Why does ffmpeg produce two different WAV formats from our fmt/704 files? The only difference between the "preservation" and "access" formats that I can see is bitrate and, therefore, file size.
- Is it possible to configure ffmpeg to produce a fmt/2 file from a fmt/704 file(or other digital audio files)? What would that command look like?
- Why does Archivematica recognize fmt/141 as a preservation format but not fmt/704?
For preservation planning purposes, I'm interested in continuing to test audio normalization for preservation and access and would love to know if we can tell Archivematica to produce fmt/2 or fmt/6 files when we normalize digital audio for preservation.
But the last question is maybe the most important. I have no reason to believe that our fmt/704 "preservation" WAV files will somehow become inaccessible or unreadable in the future but fmt/141 or other iterations of WAV will persist. In other words, normalizing preservation files received from our vendor into other preservation formats just doesn't seem to make sense. So I do just tell Archivematica that fmt/704 *is* a preservation format?
Curious to hear what others think, and I welcome any general thoughts or comments on digital audio preservation.
Thank you!
Creighton