Consider having the ability to write metadata for a folder, not just single files

[icyveins7]

My colleagues and I have gotten used to writing our recording into 1-second duration files. There are several reasons for this, one being that is far easier to see at which time instant the recording fails (samples skipped, file not written etc.). The files are otherwise all identical in terms of recording frequency, sample rate, data type etc. Having metadata for a folder would be a welcome standard.

[jacobagilbert]

I've thought about this a bit on and off, and there is a way you can do this now that should be fairly straightforward, though not SigMF Compliant or canonically endorsed by SigMF.

In the SigMF Meta Global Object there exists a relatively new field core:metadata_only which essentially states that this .sigmf-meta file is not tied directly to a specific dataset. For example, at deepsig we use this to distribute only the metadata resulting from processing IQ data.

You could conceptually apply this directly to what you are talking about doing by using this flag to indicate that this metadata applies to an entire folder, or write an extension containing a similar field extension_name:folder_metadata indicating as much.

We try to avoid noncompliance as much as possible, but sometimes it is necessary, and there are a number of endorsed non-compliant methodologies in the core specification. I'll leave this open for any further discussion about adding this idea to core or other approaches, but I think this introduces a lot of edge cases and complexity to officially support/endorse.