The Live Caption feature is one of the most useful things Google has brought to Pixel devices (possibly other Android phones soon). It generates automatic captions in real time using machine learning. It was previously available for videos with audio, but now with the introduction of the new Pixel device, they’re expanding its reach and support. You will now be able to use Live Caption for your audio and video calls, starting with the Pixel 4a.
If you need a refresher on what Live Caption is, it was originally introduced with the Pixel 2 and eventually became one of the other Pixel devices introduced since then. Basically, it gives the videos you are watching real-time captions, similar to what you would see on YouTube or the video streaming service you are watching. But this time the closed captioning is done live (hence the time) and via machine learning on your device.
With the announcement of the Pixel 4a, Live Caption gets even better as it now adds support for your audio and video calls. This is especially useful when you can’t hear the actual sound or when your background is too loud. It still uses machine learning to bring you live captions and is similar to its previous features, but this time around you can use it for your calls instead of just the videos you watch.
You can also have some sort of control over the appearance of captions. You can reposition where the closed caption box will appear on your screen or whether or not you want to hide the captions during certain particular calls or videos. You also have the option to hide profanity or turn off sound tags for certain things like laughter.
the Live captioning for voice and video calls will initially be available for the Pixel 4a. It will of course also be available on the Pixel 2, 3, 3a and Pixel 4, but it will be rolled out later via a software update.
Source: Android Community