Set movie and image formats for Keynote presentations on Mac
By default, Keynote converts HEVC videos to H.264 so they can be viewed on older Macs and older iOS devices. Images are kept in their original format regardless of whether or not the format can be viewed on iPhone and iPad. You can change these settings if you want to use movies that were formatted using High Efficiency Video Encoding (HEVC) or want to make sure images and movies can be viewed on any device.
Optimise video and image formats
The standard video compression, H.264, plays on most iOS devices, iPadOS devices and Mac computers. Video in HEVC format may not play on computers and devices with older versions of macOS and iOS.
Choose Keynote > Preferences (from the Keynote menu at the top of your screen), then click General at the top of the preferences window.
In the Adding Media section, choose a combination of options for the results you want:
Keep all movies and images in their original format: Deselect both the “Optimise movies and images for iPhone and iPad” tickbox and the “Optimise movies for older devices” tickbox. Movies and images may not display on all devices, or on all versions of macOS, iOS and iPadOS.
Convert HEVC movies and movies in unsupported formats to H.264 and images in unsupported formats to a compatible format: Select both the “Optimise movies and images for iPhone and iPad” tickbox and the “Optimise movies for older devices” tickbox. HEVC videos and videos in unsupported formats are converted to H.264 and images in unsupported formats are converted to a compatible format (for example, JPEG), and can be displayed on all devices and versions of macOS, iOS, and iPadOS.
Convert HEVC movies to H.264 but keep other movies and images in their original format: Deselect the “Optimise movies and images for iPhone and iPad” tickbox, then select the “Optimise movies for older devices” tickbox. Videos in H.264 format play on all devices and versions of macOS, iOS, and iPadOS, but videos and images in unsupported formats may not display on all devices.
Keep HEVC and H.264 movies in their original format but convert movies and images in unsupported formats: Select the “Optimise movies and images for iPhone and iPad” tickbox, then deselect the “Optimise movies for older devices” tickbox. Movies in unsupported formats are converted to H.264 unless your computer’s hardware supports HEVC encoding, in which case they’re converted to HEVC. Images in unsupported formats are converted to a compatible format (for example, JPEG).
These settings apply only to movies and images you add from now on and not to any existing movies and images in your presentations.
Note: macOS versions earlier than macOS Catalina 10.15 don’t support transparency in HEVC movies, so if your HEVC movie has transparency (for example, in the background), whatever is encoded in the movie (for example, black) is shown instead.