GZIP as a container trigger

[thorsted]

Our Rosetta Working group has identified a couple file formats which use GZIP instead of regular ZIP as a container of an existing format.

• Some institutions use GZIP to compress WARC files. They retain .gz extension, but needs a PUID as a GZIPPED Warc.
• Adobe Premiere Pro Project files also compress their XML project files with GZIP but uses ".prproj" for extension.

Could DROID add a "container" tigger and parser to identify files like this similar to ZIP/OLE?

CC2022-S01.prproj.zip

[ross-spencer]

@thorsted there's a bit of a discussion about GZIP here, I don't know exactly how close the gzip part of the discussion there is to what you're looking for here: https://github.com/digital-preservation/droid/issues/221

[thorsted]

@ross-spencer ohh, thank you. I have a vague memory of seeing this but only searched for open issues. Do you feel this is the right direction for identification or is there another way?

[ross-spencer]

@thorsted I haven't looked at it in a while. That piece was for a client (one of the statistical outputs of Dataverse) but I didn't have a massive amount of time to dig into it. I feel like we're both describing a clear two-step process - identify gzip -> identify the contents of the gzip which are known and together are their own discrete "thing" which looks a lot like container identification. Issue 221 had a broad scope which a few people strongly disagreed with, but I also feel that if technically it makes sense to treat gzip like a container, or it can be treated like a container, then there are benefits.

[thorsted]

Ran across another format based on gzip. The "Art of Illusion" AOI 3D format. Format is gzipped with a variable filename. Double problem. Art of Illusion