Many videos in Chromium are not working. The entire browsing window becomes black when you play a video, but you can hear the sound. I have the most updated Raspbian Buster upgraded with dist-upgrade, and have rebooted. I use two monitors with Raspberry Pi 4 Model B 4GB RAM, and GL (Fake KMS) desktop driver. The videos in Chromium used to work with earlier versions of Buster except that they didn't always work on Twitter. Now the videos doesn't work in e.g. YouTube and IMDB.
Here is an example of a video that does work: https://www.youtube.com/watch?v=gDeAB31eNdk
Here is an example of a video that doesn't work (browser window becomes black): https://www.youtube.com/watch?v=2Wl0cCVSpyQ
Sometimes the video shows, but is one color and striped (and perhaps magnified).
I have tried with h264ify both enabled and disabled, but no difference.
On Raspberry Pi 4, do you need h264ify? or does it not improve anything on Pi 4?
Could someone please confirm if you also have this problem, or does this work for you?