With release 0.4.6 of GSVideo (download here) users on Mac and Windows don’t need to do any extra install, since the gstreamer binaries are included inside the library package itself (Mac version uses the gstreamer binaries that are bundled with the current nightly build of songbird 1.1) . Version 0.4.5 on Windows already had this advantage, but it also presented a number of bugs that probably made it somewhat useless (most notably, gsvideo wouldn’t not be work when installed in a path containing spaces), and the included version of gstreamer had some library dependency issues. GSVideo 0.4.6 solved these two problems.
So, this version should greatly simplify the use of gsvideo on both platforms. However, there is one caveat on OSX: it requires to set the DYLD_LIBRARY_PATH environmental variable in order to work properly. Because of this, Processing needs to be started from the terminal using the following series of commands:
> cd /Applications/Processing.app/Contents/MacOS
> export DYLD_LIBRARY_PATH=/Users/username/Documents/Processing/libraries/gsvideo/library/
This assumes that GSVideo was installed in /Users/username/Documents/Processing/libraries. Clearly, this is not optimal and I’m currently looking for a workaround. I wanted to release the library anyways so people can start testing it on Mac.
Update (thanks to Chandler McWilliams): DYLD_LIBRARY_PATH can also be set permanently by editing the
~/.MacOSX/environment.plist file (more info here). The other big advantage of this approach is that Processing can be run normally from the GUI. The file gstreamerOSX-readme.rtf included with the release in sourceforge contains an example of environment.plist. But please be careful when following this method, since you can break other applications (and even the whole system) when modifying the environment.plist file (specially if typos are introduced in it). Create a backup of your environment.plist file if it already exists before making any changes, and don’t replace its entire contents with the sample I posted on sourceforge example, just add the DYLD_LIBRARY_PATH variable. Hopefully, this hack won’t be needed in the future as we find a better way to install gsvideo on OSX.