Media source blob could not be decoded

Firefox (55.02) on macOS High Sierra failed to play an online video, the console log says Media source blob could not be decoded I also tried Firefox on macOS earlier version, there is no problem, and Safari or Chrome on macOS High Sierra, no problem neither. So I thought it may be a problem with Firefox. But, then I tried Firefox on macOS High Sierra plays many other websites like Twitch, Youtube, no problem. So I am confused! What make that website so special that Firefox could not play the video? What is the possible reason for "Media source blob could not be decoded"?