Pretty significant artifacting even at 320kbps and 384kbps

So...

Opus doesn't seem to like a lot of electronic music... on this sample in particular it's having issues...

Here's the lossless

https://drive.google.com/file/d/1ERvzuTO86OcSTBcI7uOLlrY5dGaTE8Px/view?usp=sharing

Especially near the beginning and middle... near the end the music changes and I don't think it's as audible (but then again, I didn't test the end of the sample much... as I was hearing a lot of artifacting in the beginning and middle)

At 48kbps it has pretty much the same artifacting but MUCH more audible... it's mainly in the 0-1khz range... same with 320kbps

This is the sample encoded with Opus at 48kbps

https://drive.google.com/file/d/1DQrGaXP82Wx1H20nlPKtGY7Fts91i6nh/view?usp=sharing

It's whirling/thumping sounds that I'm hearing... mostly artifacts in the 0-1khz range... at 48kbps it's understandable... but at 320.... not so much

Oh, and here's the ABX test of 320kbps Opus versus lossless

https://i.imgur.com/FIsTWC4.png

It seems to be issues with mostly electronic music... at least, I think...

I used 1.2.1 Opus and VBR

As a comparison to AAC at 48kbps... you can tell it is a lot better because it doesn't have those whirling effects... or at least, drastically reduced

https://drive.google.com/file/d/1R36tsP0NrSxFvekfyeWXSzFMTK_YzkbV/view?usp=sharing

Now, AAC did use about 7% more bitrate overall... but even then... it's a LOT better

Start by downloading the linked lossless sample and reproducing the report with Opus 1.2.1 in VBR at 48, 320, and 384 kbps. Compare the results with the linked ABX evidence and AAC sample; the issue is complete when the artifacting has been investigated and a reproducible cause or resolution is documented.