Digital Preservation Q&A - Recent questions tagged metadata

How/where to store metadata about optical media sector layout in METS/PREMIS

Mon, 05 Feb 2018 16:09:33 +0000

I'm drafting a METS/PREMIS profile for images/rips of optical media images (ISOs for data sessions; WAV or FLAC files for audio). One of the pieces of metadata I'd like to include is the output of the cd-info tool, which contains information about the sector layout of the disc. Here's an example:

https://gist.github.com/bitsgalore/9a2838481574c040f7c4b7da4ed59926

However I'm unsure how (and where) to store this info in METS. My initial idea was something like this:

Create a METS techMD element which is associated with the structmap div element that encompasses all files that were extracted from the physical disc (typically one ISO image and/or multiple audio files).
Inside this techMD element, create a PREMIS OBJECT instance with xsi:type="premis:representation" (since it describes the disc as a whole, and not an individual ISO image or audio file!)
Then use PREMIS unit 1.5.7 objectCharacteristicsExtension as a container for wrapping the iso-info output.

The problem here is that the PREMIS 3.0 data dictionary says that the objectCharacteristicsExtension unit (and also its parent unit 1.5 objectCharacteristics) is "Not Applicable" for the intellectual Entity and Representation object types!

This makes me wonder how others are handling this. Is this an oversight of PREMIS, or is there some other (possibly
better) way to do this that I've overlooked?

Any suggestions appreciated!

Best method to record track playing order for ripped audio CDs

Tue, 20 Oct 2015 13:52:30 +0000

Although there’s quite a bit of info on the web on audio CD preservation, most of the resources I found tend to focus on the audio ripping process. However, when you rip a CD to a bunch of audio files, it’s important that the original playing order of the tracks is recorded somewhere. Of course you can (and should!) do this at the preservation metadata level, but for access you also want to have some mechanism that allows an end user to hear the individual tracks in their original playing order (e.g. in a multimedia player application). From the top of my head I can think of 2 general approaches to achieve this:

Record the playing order inside the audio files themselves, e.g. using “Track Number” tags that are embedded as RIFF Info or ID3 tags.
Use a separate play list file. For this several formats exist, such as M3U and XSPF.

The main problem I see is that all of the above methods are supported by some players (and not by others), but I have have some difficulty in judging which approach would ensure the most widespread support. This made me wonder if there are any recommended best practices for this? What are other people doing?

Tool(s) for extracting administrative metadata from WARC?

Thu, 29 Jan 2015 07:08:14 +0000

I'm researching best practices for administrative metadata--preservation metadata in particular--for web archives. So far I've found some very helpful rationales and schemas, all PREMIS-in-METS-based, but I haven't seen anything that directly explains how one gets from point A to point B. That is, I haven't seen any descriptions of the steps nor the tools used to actually extract this type of metadata (or as much as can reasonably be gleaned) from WARCs. Have you? Have you extracted administrative metadata from your WARCs and lived to tell the tale? I'd love to know what you used and what you thought of the process.

What is a good way to record information about the funding of a preservation project?

Fri, 07 Nov 2014 17:41:37 +0000

Many digital preservation projects are funded by grants or donation. Analogous to naming a reading room, marking a shelf with a brass plaque, or placing a sticker in the book, I think it's important to recognize these contributions with something. Metadata seems like a good place to record this. For example,

<agent><agentName>Digital forensics workstation</agentName><donor>Generous foundation</donor><agent>

or

<event><eventType>Digitization</eventType><funder>NHPRC</funder></event>

or

<collection><name>Famous writer's hard drive</name><creator>Famous writer</creator><donor>Person who purchased collection at auction</donor></collection>

I scanned through PREMIS, METS, and EAD, but couldn't find anything. Does anyone record this information in a structured way and can they share advice on how they do it?

What is "Preservation Metadata"?

Wed, 14 May 2014 12:10:13 +0000

I often see 'preservation metadata' used in sentences which suggest it is distinct from other types of metadata, e.g. distinct from 'descriptive', 'structural', 'rights' or 'technical' metadata. However, it would seem that these "other" forms of metadata also have a part to play in preserving digital material, for example technical metadata about an image's dimensions could be used within Quality Assurance processes.

So, is 'preservation metadata' a distinct class/set of metadata? And if so, what does that set constitute?

Or should 'preservation metadata' be used to cover all metadata useful for preserving material, irrespective of whether it is 'descriptive', 'techincal', etc.?