I am also having similar issues - not entirely consistent, however, and sharing audio does not seem to work at all. It seems to be related to codecs and how different browsers utilize them.
2026-06-28T20:28:18.119Z INFO livekit.pub rtc/participant.go:2964 falling back to alternative video codec {"room": "guild_1516566176715505664_channel_1516566176715505714", "roomID": "RM_MTUkFSzzFNaj", "participant": "user_1516880839143587840_dropbear-acoustic", "participantID": "PA_PgWhnEvhSP68", "remote": false, "codec": "video/h264", "altCodec": "video/rtx", "enabledPublishCodecs": [{"mime": "video/rtx"}, {"mime": "audio/opus"}], "trackID": "TR_VSHpeTf7sU4mm8"}
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Comment by @zixhaa
2026-06-28T20:28:18.119Z INFO livekit.pub rtc/participant.go:2964 falling back to alternative video codec {"room": "guild_1516566176715505664_channel_1516566176715505714", "roomID": "RM_MTUkFSzzFNaj", "participant": "user_1516880839143587840_dropbear-acoustic", "participantID": "PA_PgWhnEvhSP68", "remote": false, "codec": "video/h264", "altCodec": "video/rtx", "enabledPublishCodecs": [{"mime": "video/rtx"}, {"mime": "audio/opus"}], "trackID": "TR_VSHpeTf7sU4mm8"}