While Microsoft publishes changelogs and release notes about the improvements and changes it announces in new builds and OS updates, sometimes there are a lot of unannounced changes put in there as well. And on rare occasions, these changes actually lower the quality of some things instead of enhancing them.
Last year in July, it was found that Microsoft had quietly reduced the quality of the startup sound on Windows 11 22H2. Depending on the compression algorithm used, be it Huffman or Arithmetic or something else, the difference may or may not have been perceptible even though it was sizable reduction in bitrate.
Likewise, right around the same time, Microsoft it seems, had also tweaked the Windows 11 Out of Box Experience (OOBE) animation and had reduced it. This time, unlike with the startup sound, the difference is likely perceptible as the framerate of this animation was halved from 60 fps down to just 30 fps.
As you can see in the image above, aside from the framerate, the data rate has also been reduced by around two and a half times from 1914 Kbps to 741 Kbps. The overall bitrate is down from 2235 Kbps to 1063 Kbps. There is no change in the audio fidelity though.
Source: Xeno (Twitter)