Set a subtitle language using ffmpeg

Question

I tried googling a way to set the language of a subtitle stream with ffmpeg and found the -slang option. So I tried the following command but immediately receive an error:

Answer 1

After some research, found the reason why -slang didn't work. In fact you use a recent version of ffmpeg and it's a good thing but if the documentation still describe the option, you can find in the ChangeLog:

version 0.9:
...
 * -metadata can now be used to set metadata on streams and chapters, e.g.
      -metadata:s:1 language=eng sets the language of the first stream to 'eng'.
      This made -vlang/-alang/-slang options redundant, so they were removed.

When you find a command line example, check if the option used are in Your version of ffmpeg.

 ffmpeg --help >> ffmpeg-doc.txt

The -slang option isn't in.

But it also proof that the on-line documentation about ffmpeg is sometime incorrect regarding the code change.