Did you know that many of the old videos you keep stored and encoded in outdated formats may refuse to play under macOS 10.15 Catalina without some third party help?

That’s because macOS Catalina dropped support for 32-bit apps and Apple’s never bothered to update software components for decoding older video formats to 64-bit compatibility.

Apple’s support document lists more than three dozen older media formats affected by the transition to 64-bit technology in macOS Catalina, like RealVideo, DivX, Sorenson 3 and FlashPix, in addition to other formats that were superseded by improved encoders:

Examples of media that will be affected by the transition to 64-bit technology include video files from early Flip Video cameras that use the 3ivx codec, early web videos encoded with the Sorenson codec and media converted from DVD to the DivX format.

As a result, apps like iMovie and QuickTime Player cannot play those old formats in Catalina. It may also mean more work for developers to ensure compatibility, Apple indicates:

Third-party developers may continue to offer compatibility with some formats by building support directly into their apps. Contact developers of third-party apps for more information about media formats supported in their apps.

MacWorld’s Glenn Fleischman has more details:

iMovie and Final Cut Pro were both updated in March 2019 so that when running under macOS 10.14 Mojave and some previous compatible releases, the apps alerted you when any project you opened contained clips that would be incompatible in Catalina and converted them to a newer format.

You could also open any file in QuickTime Player in Mojave or earlier releases and save a copy, which would automatically save it in a newer format that will work in Catalina.

What you cannot do, however, is convert old videos in iMovie, Final Cut Pro or QuickTime Player on Catalina-powered systems. Apple’s decision affects any apps that support video playback via standard system calls. Third-party video players using their own media decoding technology continue to work properly on Catalina and should be used to play old videos.

TUTORIAL: How to create Picture-in-Picture video in iMovie

VLC by VideoLAN is one such app. The free VLC software is available across different platforms and it includes rich, robust support for dozens upon dozens of video formats that are unsupported out of the box in macOS, including a plethora of obscure video formats.

VLC can both play and convert video formats.

IINA is a modern media player for macOS

If you dislike VLC for its unusual user interface that lacks some Mac-specific native options, you should give the free IINA app, pictured above, a try. IINA is a modern macOS media player that not only adopts Apple’s clean post-Yosemite design language, but also the company’s underlying platform technologies such as Force Touch, Touch Bar and Picture-in-Picture.

Have you noticed problems with Catalina’s support for old video formats?

I’ve long stopped encoding my videos in non-Apple formats so that’s not even an issue for me. On the other hand, I don’t do video for a living so that’s why I’m not concerned about this.

How about you?