On the current version of the Unity Recorder 4.0.0-pre.1 it is not possible to record audio or video outside of the Unity Editor (i.e., builds/standalone player).
I noticed that this was asked back in 2017 , which was replied to with a mention that it was a feature that would come someday, but no ETA was given at the time.
No there is no estimate for this yet. There are many obstacles to making it work, including the licensing of codecs, cross-platform support, and disk space management.
So I may better understand, when Unity releases a package/feature, does it always have to be cross-platform from the beginning or can it be limited to only a select number of platforms and then extended to others with future updates?
I ask because I imagine getting this to work on the standard computer platforms (Windows, Mac OS, Linux) shouldn’t be much of a problem as it would be closer to what is done in the Unity Editor on those platforms, but it would be difficult on other platforms, like mobile devices, due to disk space management and codec compatibility.
It doesn’t have to be cross-platform, and often we focus on supporting the most essential platforms first.
Playmode recording is something that a few people have asked so we are aware of this need. Lately, we’ve been focusing on reducing the number of bugs in Recorder. There are already a lot of new things in the pipeline in terms of features and improvements, and we will address this request when possible. Cheers