Back in the spring, Google demonstrated an awesome Live Caption feature that was supposed to be arriving with Android 10, but the fine print said only for "select phones." Unlike Live Transcribe, we are yet to see Live Caption materialize on any handset, select or not, but with the arrival of Pixel 4, all that will change, it seems.
XDA-Devs tested it with YouTube, Google Podcasts, Google Photos, Amazon Prime Video and Netflix, and it worked everywhere.
As you can see in the video demo above, the overlay positioning is often not ideal, and the captioning is hit or miss, especially when a new phrase is introduced - it captions the fresh OnePlus 7T as 17, for instance - but, overall, this feature would be a godsend for all mumble rappers out there.
As you can see in the screenshot here, Live Caption can be turned on and off from the pulled-down status bar, so it's made really easy to take advantage of, if you don't get what someone is saying in a video, or are not a native speaker and captions help follow the plotline better.
The Live Caption feature will only be available on high-end phones, of course, as it needs significant resources to function but we should be able to test it out fully as soon as Pixel 4 rolls in in two weeks or so.