I'm using Ocenaudio ver. 3.7.18 on a MacBook running Catalina 10.15.5. Ocenaudio opens both .mp3 and .m4a files just fine, as did ver. 3.7.9. I started using Ocenaudio when Audacity quit working in the move to 64 bit apps, and I will not go back when Audacity is fixed. Ocenaudio is much faster and I found the interface more flexible and elegant than Audacity after using it a while.

Not sure how this could be, but it would appear this app somehow does not support .mp3, nor .m4a files. Wasn't able to find a list of compatible file formats on the App Store page, or even on their website. Don;t know if this could be a temporary issue do to the upgrade to Catalina. Would be hard to believe this app cannot open these very common file formate. It seems that the previous version of this app was fairly recommended online, but I haven't been able to get it to work with any audio files I own.

This will not open or export to mp3 file format. That makes it useless for any kind of serious work. I didn't even bother checking other features when I confirmed the previous reviewer's assessment.