Syntax for never/always compress

I can’t find any documentation, how to specify the values for --add-never-compress: is it .mp4, mp4 or *.mp4 and is it case insensitive?

I looked at the relevant source code:

  • it is not a glob pattern, it is matched against the result of path/filePath.Ext(), which takes the extension from the current file. The string must include the dot: .mp4
  • the match is case sensitive.
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Is it comma or whitespace seperated?
A full example would be helpfull e.g. --add-never-compress=.mp4 .MP4 .7z .7Z or --add-never-compress=".mp4 .MP4 .7z .7Z"

A list of extension can be found here

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I was just testing this and the only thing I could make work was to add a separate flag for each instance eg.

--add-never-compress=.mp4 --add-never-compress=.7z

or to save some effort:
--add-never-compress=.[mM][pP]4 --add-never-compress=.7[zZ]

if you do --add-never-compress=.aac,.mp3 it’ll literally enter “.aac,.mp3”

Would love to learn of a better option! I have way too many for this dediousness so I use the UI to enter it for the time being.


According to:

If you don’t use really “heavy” compression methods, you don’t need “exclude” already compressed files.