The programs in the full Klipspringer platform as well as the codec library decode Ogg Opus audio by invoking the official opusfile API, and need the opusfile library to be installed before the Klipspringer platform can be built with Ogg Opus support. If you aren’t interested in playing Ogg Opus (.opus) files, just ignore warnings about it from configure, and install without Opus support.
Klipspringer currently supports decoding only for Opus, not encoding to create files or stream in Ogg Opus format.
On many systems, the opusfile library is simple to install using the package manager. For instance, on Debian-based Linuxes (such as Ubuntu and Raspberry Pi OS, you can just enter
sudo apt-get install libopusfile-dev
in the terminal. On macOS it’s almost as easy if you use Homebrew: use the command
brew install opusfile
If none of these installation methods works on your system, you might find useful suggestions on the official Opus page.