I have some videos (H.264) cannot be played on mobile browsers but can be played on desktop browsers. I use the same browsers (Chrome, Safari) on both desktop and mobiles. However the video control on mobile browser is blank and seems like the video is not loaded correctly.

I am really confused about this issue, and the code I use is really simple:

<video controls style="width:100%"><source src="" type="video/mp4"></video>