Cannot play videos in in macOS Finder Upgraded on 2018/03/28

After restart macOS, Safari/Google Chrome cannot play embedded videos. 

But...

In macOS I opened Finder and located a mp4 file, press space to quick view the content. I got a blank window with a loading icon. (This video can be played in this way yesterday.)

I use ctrl+click and select Open with, use QuickTime to play it. But QuickTime responded an error said The document "xxxx" could not be opened. An unknown error occurred (-101).



Original question

Safari/Google Chrome cannot play embedded videos in website. I can see the 1st frame of the video and I can drag the progress bar to move the timeframe, it shows the frames. But when I clicked play button the video does not get played.

In Google Chrome I have tried:


Disabling the hardware acceleration.
Disabling the Ad Blocker.
Clearing the browser data.
Disabling the QUIC protocol.


In Safari I have tried:


Allowed auto play for videos with sounds


The websites in question are not using Flash, just HTML5 video.

I am running macOS High Sierra 10.13.3 with Google Chrome 66.0.3359.45 (beta-64bit) and Safari 11.0.3.
After contacted Apple Support I got this problem resolved, by using the following steps.


Shut down Mac
Unplug all external devices. To me they are bluetooth keyboard and trackpad
Start Mac and hold on Command + Option + P + R immediately
Mac tried to restart (the screen turned on and off)
Release Command + Option + P + R, let Mac restarted


"Command + Option + P + R" cleared PRAM and let Mac re-exam all hardwares and build correct info into PRAM.

For more information about it please refer https://discussions.apple.com/thread/1788029