Your simplest solution would be to upload your video to youtube, maybe run your webpage in a window with a live link to the youtube address then follow my previously suggested workaround for displaying Youtube videos:
After hours of seeking solutions to play YOUTUBE videos, I have found the solution in the Epiphany Browser. Installs with the following 3 commands:
sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install epiphany-browser
BUT THEN:
You must reboot, then (AGAIN!):
sudo apt-get update
Then navigate to www.youtube.com/html5 check off use HTML5 player. In the RPi's operating system's sound icon, right click and check "Analog" then plug in headphones or speakers into the Pi jack (HDMI setting here, did not provide adequate quality)
I have experienced most youtube videos to play well with these steps, the exceptions I've found are some music videos. All videos seem to retain the white on red Youtube play button throughout the video, smack in the center of the screen throughout... If the video will play, the play button will stop blinking within 30 seconds, right clicking, then reload will work, after another video selection has been made. Pause will not work; & any mouse movements after the video has started affects the sound...if you can put up with these inconveniences, welcome to Youtube on a slice of Pi !