Plugin creation (metadata format)

I want to create a plugin that allows users to enter certain metadata for use on the air for a radio station. That will include certain things such as artist, title, whether the song fades or ends cold, an EOM (end of message) marker, a kill date (don’t play after this date/time), etc.

I know I can add fields in the metadata editor, but this metadata will need to be saved on a certain proprietary wav file format. It’s proprietary but the specific format is available for use. There are plugins available for several versions of Adobe Audition. I want to create one for Audacity.

Can this be done as a plugin or would I need to get the source and rewrite the wav format structure and metadata editor to accomplish this?

I don’t think it can be done with a plug-in, unless you write a plug-in that handles the encoding and file writing itself. (Nyquist plug-ins don’t support writing metadata).

On possible approach:
If you have a command-line encoder for your “certain proprietary wav file format”, then you could (manually) enter the appropriate command line arguments into Audacity’s “external encoder” export:

Are you 100% sure it’s a proprietary wav format and not just “normal” wav with a BWF chunk added?

What would the advantage/s be to adding this to Audacity?
Are the clips/music being edited, cleaned or otherwise manipulated in Audacity hence the reason to add the metadata when finished?
(Sorry, just curious).

If so, then it makes sense, else going by what Steve has written, it’s probably better to use a standalone metadata editor which may,
or may not be linked to Audacity.

…the specific format is available for use…

Depending on the complexity, maybe as easy as finding the offsets (beginning and end) in the file, which will probably be fixed,
and writing something to do as follows:

Open file in raw mode up to 1 byte before start of metadata.
Get metadata from user input (GUI, cmd line, whatever) do a sanity check and add to the file.
Get rest of file from 1 byte after end of metadata region, append and write out new file.

Are you 100% sure it’s a proprietary wav format and not just “normal” wav with a BWF chunk added?

What he said.

That sure sounds like Broadcast WAV to me.