Video. Why can’t I hear sound on mobile devices?

Hi all!

Why can’t I hear sound on mobile devices?

Additional questions:

How to resize a video?
How to change the content of a video something like setTexture() on a sprite?
How to change position?
How do I know if a video has played to the end?

Video_1 = this.add.video(110, 310, ‘video_1’);
Video_1.realWidth = 1000;
Video_1.play(true);

Video_2 = this.add.video(510, 310, ‘video_2’);
Video_2.realWidth = 1000;
Video_2.play(true);

Thank you.

It remains to be seen why the video does not play sound on mobile devices.
What could be the reason?

Usually you have to tap first.

What did you use in load.video(…)?

Sorry for the long answer. The problem resolved itself.