TL;DR: Apple has updated the mute key on the MacBook Air M4 to feature a speaker symbol with a strikethrough line, replacing the previous design used since 1999. The latter had no strikethrough ...

7. Tap the audio button. You should see it change to a mute symbol, and the audio slider should move all the way to the left. 8. When you're done editing the video, tap "Done" at the upper left ...

Before, the mute button merely showed a speaker symbol without any sign that it was meant to silence sound. The macOS interface, on the other hand, has always indicated a speaker with a strikeout ...