Relaunching this topic, is Poweramp supposed to read the "non-standard" REPLAYGAIN_ tags in Opus files (.opus, not in an Ogg container) instead of the R128_ ones specified in the RFC? "Info/Tags" doesn't mention anything about ReplayGain, here. By the way, is the "Audio Info" pane supposed to show something about ReplayGain when it's found and applied?
Here are the tags found in an example file:
$ ffprobe -hide_banner 06.\ Jomfrulysets\ fall.opus
Input #0, ogg, from '06. Jomfrulysets fall.opus':
Duration: 00:06:45.77, start: 0.000000, bitrate: 148 kb/s
Stream #0:0: Audio: opus, 48000 Hz, stereo, fltp
Metadata:
encoder : Lavc60.3.100 libopus
REPLAYGAIN_ALGORITHM: BS.1770
REPLAYGAIN_REFERENCE_LOUDNESS: -18.0 dBFS
REPLAYGAIN_TRACK_GAIN: -2.6 dB
REPLAYGAIN_TRACK_PEAK: 1.003636
REPLAYGAIN_ALBUM_GAIN: -2.7 dB
REPLAYGAIN_ALBUM_PEAK: 1.040768
TITLE : Jomfrulysets fall
track : 06
TRACKTOTAL : 8
ARTIST : Joyless
album_artist : Joyless
ALBUM : Unlimited Hate
DATE : 1996