Passing metafield values to the postprocessor using --postprocessor-args

[erakin]

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Could it be possible to pass metafield values to the post-processor using --postprocessor-args?
An example would be to set the playlist name to the album field by doing

--postprocessor-args "-metadata album=%(playlist)s"

[erakin]

I have found a pull request addressing this issue #17904 .