Okay ... thanks!
1. first I ran the home brew install via terminal ... and wound up with this ...
==> Installation successful!
==> Homebrew has enabled anonymous aggregate user behaviour analytics.
Read the analytics documentation (and how to opt-out) here:
https://git.io/brew-analytics
==> Next steps:
- Run `brew help` to get started
- Further documentation:
https://git.io/brew-docs
2. and then I ran this, as per you instructions:
Wills-Mac-Pro:Wiki.app willfriedwald$ brew install libdvdcss
==> Downloading
https://homebrew.bintray.com/bottles/libdvdcss-1.4.0.el_capitan.bottle.1.tar.gz
######################################################################## 100.0%
==> Pouring libdvdcss-1.4.0.el_capitan.bottle.1.tar.gz
3. but I got this:
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
Could not symlink lib/libdvdcss.2.dylib
Target /usr/local/lib/libdvdcss.2.dylib
already exists. You may want to remove it:
rm '/usr/local/lib/libdvdcss.2.dylib'
To force the link and overwrite all conflicting files:
brew link --overwrite libdvdcss
To list all files that would be deleted:
brew link --overwrite --dry-run libdvdcss
Possible conflicting files are:
/usr/local/lib/libdvdcss.2.dylib
==> Summary
/usr/local/Cellar/libdvdcss/1.4.0: 17 files, 355.4K
4. so I did this:
Wills-Mac-Pro:Wiki.app willfriedwald$ brew link --overwrite libdvdcss
Linking /usr/local/Cellar/libdvdcss/1.4.0... 6 symlinks created
Wills-Mac-Pro:Wiki.app willfriedwald$
that seems to have worked, right? Now let me try HB one more time ....
Rats! Still, "No valid source found" - I could re-starting a second time ???