Apple’s simple slideshow feature is limited and cannot slow down or remove music fully. The correct way is:
On Mac:
- Use Create Slideshow (not Play Slideshow) → control speed, remove music, play full video sound
- Or use QuickTime to play all items with full video and audio
- Or export a custom video
On iPhone:
- Use Memories and set Music → None + Video Length → Long
- Or use iMovie for full control
- Built-in slideshow always shortens videos, so avoid it
This guarantees your video audio plays 100%, with no music, at the speed you want, on both Mac and iPhone.
