Installing openh264 on ubuntu 18.04 for opencv python

I want to write the frames to video file with .mp4 extension. I am able to create the video using avc1 codec after manipulating the frames. But the size of the video increases. So, I tried to install openh264 on Ubuntu using the following commands

  1. sudo add-apt-repository ppa:djcj/hybrid (But I get the message as ppa discontinued)

2.sudo apt-get update

  1. sudo apt-get install openh264 ( I get the message as E: Unable to locate package openh264)
    How to install openh264 for opencv python on ubuntu 18.04?