There are a few protocols or types of video online, the main ones are HTML5
and Flash; for several reasons iOS Devices generally do not use Flash. The
sites you visit may have a secondary mobile-OS based element for video.
The android OS has one of the other non-Flash software... (unity, html5, etc)
A history (from seven years ago) about HTML5 and Flash:
Rather than use Flash, Apple has adopted HTML5, CSS and JavaScript -
all open standards. Apple's mobile devices all ship with high performance, ...
https://www.apple.com/hotnews/thoughts-on-flash/
HTML5 vs Native: The Mobile App Debate - HTML5 Rocks
HTML5 vs Native: The Mobile App Debate HTML5 Rocks. Table ...
Mobile apps and HTML5 are two of the hottest ... And the latest iOS
browser supports WebSocket ...
https://www.html5rocks.com/en/mobile/nativedebate/
iOS vs. Android vs. HTML5 - Making the Decision
It's been said that in regards to the question of which mobile platform is the
best target for development, the answer... develop for the mobile web. HTML5
business2community.com/mobile-apps/ios-vs-android-
Some additional perspectives and reading can be found among
resulting search finds online, such as this one from duck-duck-go:
https://duckduckgo.com/?q=flash+for+iOS+vs+HTML5&t=ffsb&ia=web
In any event...
Good luck & happy trails! 🙂