What is the primary source of Hi-Res audio files?

On streaming services like Tidal an Qobuz, do they have access to the masters from which they convert to some Hi-Res bitrate? If not, what’s the point?

I mean, surely they’re not simply upconverting CD quality source audio to 24/96 and calling it “Hi-Res”. Are there any regulations to disallow this?

Roon upsamples music files based on user settings. Native, or assigned higher bit rates.

Tidal Masters (MQA) are re-released at higher bit rates…the exact engineering methods are beyond me, but this article might help explain.

No upsampling or MQA origami hocuspocus by Qobuz. They do the preliminary work with recording studios, in partnership with record labels and film studios, to obtain 24-Bit Hi-Res files with an identical sound to that of the engineer’s studio master.

Qobuz demands that the studio masters it receives from its partnering record labels are at a minimum resolution of 24-bit/88kHz, and the files it serves go as high as 24-bit/192kHz. Through Qobuz’s process of turning a studio master into a user-ready file, there’s no upsampling, and no interference with the integrity of the audio.

” Hi-Res (as in High-Resolution) represents the apex of digital audio. These files - obtained through lossless compression or uncompressed - deliver better sound quality than a CD. They are encoded in 24-Bit, at frequencies that can go up to 192 kHz - these are actually the same files that are used in recording studios.
They therefore offer a much more accurate, faithful and respectful reproduction of the work of artists and sound engineers than any other audio file format.”