The latest update 10.4.6 for Final Cut Pro X as well as iMovie 10.1.11 brings bugfixes and a foretaste of the changes due to the big OS upgrade to macOS 10.15, which is expected in autumn 2019. Video editing will be particularly affected: as Apple had already announced with the FCPX update 10.4.4, the OS conversion to 64-bit will herald the end of the QuickTime 7 framework.
The end of the QT framework also means the end of support for third-party codecs at the operating system level. This is because codecs from other manufacturers are only integrated at the macOS operating system level using the 32-bit QuickTime API. Apple's current codec framework AV Foundation does not support dynamic integration of third-party codecs. The result is a problem for all manufacturers of video apps for macOS who will not use codecs supported by the OS in the future - they will then have to integrate their own codec parsers into their programs (e.g. based on the open source ffmpeg) in order to be able to continue working with these codecs.
Not applicable will support old codecs ("legacy media") like Sony's HDCAM-SR, GoPro's Cineform, Avid's DNxHD/DNxHR and among others 3ivx MPEG-4, AV1/VP9, Sorenson Video / Video 3 / YUV9, AVC0/AVA0-Media, Cinepak, CineForm, DivX, Flash Video and JPEG 2000.
The good news: Apple had previously warned users to convert these formats manually, but now Apple is helping FCPX and iMovie users with this step. With the latest update for both applications, Apple is automatically converting old video formats into new compatible formats, so that old content is not inaccessible after the big macOS update 10.15. After the update to Compressor 4.4.4 or Motion 5.4.3, users of Compressor and Motion will be notified of media that will not be compatible in the future, but the USer will then have to convert manually using FCPX or iMovie.
Here is the complete list of bugfixes and new features of the 10.4.6 FCPX update: -Detects media files that Mojave says are not compatible with future versions of macOS and converts them to a compatible format. -Fixes a problem where the share targets could disappear from the Share menu after exiting Final Cut Pro. -Fixes an issue where the Workflow Extension button could disappear when you resize the user interface. -Fixes an issue where the Select Clip command could incorrectly select the clip under the playhead. -Fixes an issue where a successful share notification appears after the process is canceled. -Fixes an issue where frames saved in the frame browser of the Compare Viewer may look different from frames saved in the Viewer. -Fixes an issue where frequency information for Hum removal might not be visible in the audio inspector. -Fixes an issue where linked media can be displayed with black thumbnails in the browser and timeline. Fixes an issue where the Sharing menu might be hidden behind the viewer when you use Final Cut Pro in full-screen mode. -Improves reliability when sharing videos on YouTube.