Apple is teasing a major Apple Music announcement. “Get ready,” a post in the service’s Browse tab reads, “music is about to change forever.” Tapping the image reveals an animated video, though it just consists of the music streaming service’s logo spinning in place. The teaser, first reported by MacRumors, is believed to refer to Apple Music’s rumored lossless and hi-res music streaming features.

A launch of the new higher quality streaming is believed to be imminent after code referencing “Lossless” and “Hi Res Lossless” streaming tiers appeared in the service’s Android and web apps. According to code in the Android app, the lossless tier will support music streaming at 24-bit/48Hz (a small step up from regular CD-quality 16-bit/44.1kHz), while the hi-res lossless tier will stream at 24-bit/192 kHz.

Code in the Android app warns that these higher quality tiers will required more storage space and data to stream compared to existing quality. Apple Music’s current high quality tier consumes 6 MB of data for a 3-minute song, but this could rise to 36 MB with lossless, and 145 MB with hi-res lossless.

The benefit, of course, should be better sounding audio, similar to what’s already offered by the likes of Tidal, Amazon Music HD, and Deezer. Spotify has also announced its own lossless HiFi tier which is due to launch later this year.

As well as lossless and hi-res streaming, code snippets also include mentions of “Dolby Audio” and “Dolby Atmos,” 9to5Mac reports. The speculation is that the AirPods’ Spatial Audio features could be used in conjunction with Dolby’s surround sound technology.

Apple’s teaser doesn’t say when we should expect an official announcement, but some rumors suggest an announcement as early as Tuesday.