On iOS Safari browsers I've observed that on first page load, the video controls respond to mute/unmute regardless of the state of the silent toggle. When you navigate away from the page and later go back to the video, the video controls no longer respond to mute/unmute.
To recreate:
- On iOS device, open Html 5 Video Tryit
- Ensure iPhone silent toggle is ON. (muted)
- Play video, mute/unmute; Cool it works with the toggle on
- Click ad at top of page; Just to navigate somewhere else
- Use back button and attempt step 3; Video is always muted
I've tried debugging through both scenarios and validated video mute state changes were occurring as expected. Appears to be iOS Safari bug, but looking for work around.