On the release notes page for the Second Life Project VLC Media Plugin/18.104.22.1686258 viewer there is an update on QuickTime which is very important. Recently Apple confirmed they will no longer be releasing any more security updates for the PC version going forward.
This latest Second Life project viewer now uses LibVLC replacing the original QuickTime media plugin for Windows versions of Second Life. This is a reasonable path forward and I think it will be interesting to see how LibVLC performs in the months ahead.
As many know already QuickTime in Second Life uses media types like MPEG-4, MP3 and MOV. In the near future the OS X viewer will be updated to LibVLC so stay tuned for that.
Apple recently announced that they are no longer supporting QuickTime for Windows and most importantly, will not be providing security updates going forwards. We use QuickTime in the viewer to play back media type likes MP3 MPEG-4 and of course MOV.
This viewer replaces the QuickTime media plugin for the Windows version of the viewer with one based on LibVLC (https://wiki.videolan.org/LibVLC/). The OS X viewer is unchanged since Apple will continue to support QuickTime there.
Eventually, as part of the update to 64 bit versions of the viewers, the OS X viewer will also be updated to use LibVLC (QuickTime APIs are Carbon and not available as 64bit).
More information can be found here.