I have a bunch of pictures and videos imported from my iPhone to my M4 MacBook air. When I replay the videos, they run at normal speed for a few seconds and then the replay speed goes to maybe 50% and the audio drops out. These are only located on my MacBook and haven't been uploaded to iCloud.
I cant see any settings or a way to view these normally. Is there an issue with Photos app (ver 10.0)
MacBook Air 13″, macOS 15.5
Obviously you have shot such movie with high frame rate.
iOS/iPadOS 18 introduced QuickTime FullFrameRatePlaybackIntent tag:
"key that represents whether this movie should play at full frame rate
Some apps play movies recorded at frame rates of 120fps or higher in slow motion. If your app records high-frame-rate movies, you can add this movie-level metadata to indicate whether the movie intends to play at the full frame rate (1) or at a slow motion rate (0). Apps that play movies may use this metadata, when present, to guide their behavior."
quickTimeMetadataKeyFullFrameRatePlaybackIntent | Apple Developer Documentation
macOS 15 Sequoia QuickTime Player plays middle part of high frame rate movies (seems to be ≈85 fps or more) in slow-motion without that tag (earlier macOS like Ventura seem to behave the same).
For example, the whole movie plays at 250 fps in Sequoia after adding or editing:
exiftool -m -P -overwrite_original -api LargeFileSupport=1 -ext mov -Keys:FullFrameRatePlaybackIntent=1 output.mov
Back to the default slow-motion behavior:
exiftool -m -P -overwrite_original -api LargeFileSupport=1 -ext mov -Keys:FullFrameRatePlaybackIntent=0 output.mov
Or just delete FullFrameRatePlaybackIntent tag:
exiftool -m -P -overwrite_original -api LargeFileSupport=1 -ext mov -Keys:FullFrameRatePlaybackIntent= output.mov
Literally a few seconds, or is it just a second or less? Videos taken in "Slo-mo" (intentionally or not) can behave as you describe, but the normal motion is usually just a fraction of a second at the start and end of the video.
If they are Slo-mo videos, you should be able to change the playback rate in Edit mode in several steps by % of full speed and fps (frames per second).
Thanks Matti, looks like you've found the reason. My videos are recorded on an iPhone 16 Pro at 120fps.
Does the above command make it so the videos will play normally or are they changed to have a lower frame rate. Additionally I'm not sure if I am required to do this for each file or how often to run the command.
Sequoia QuickTime Player plays middle part of high frame rate movies (seems to be ≈85 fps or more) in slow-motion.
That can be prevented by adding or editing FullFrameRatePlaybackIntent tag to value 1 with:
exiftool -m -P -overwrite_original -ext mov -Keys:FullFrameRatePlaybackIntent=1 movie.mov
Or by playing such movie with Sequoia QuickLook or some app like IINA that does not honor that tag. Then the whole high frame rate movie is played in normal speed (if the device can handle that).
That tag can be set back to the "middle part slow-motion" option with:
exiftool -m -P -overwrite_original -ext mov -Keys:FullFrameRatePlaybackIntent=0 movie.mov
Or by deleting that tag with:
exiftool -m -P -overwrite_original -ext mov -Keys:FullFrameRatePlaybackIntent= movie.mov
On the other hand, Sequoia Photos.app seems to play the middle part of high frame rate movies in slow motion no matter what.
Photo app videos play normal speed for few second and then slow down