Sadly my old "64 MB" (not really, it's 128 MB IIRC) player doesn't support OPUS. It's there where I have to fallback to AAC or MP3. But it luckily supports FLAC

Sadly my old "64 MB" (not really, it's 128 MB IIRC) player doesn't support OPUS. It's there where I have to fallback to AAC or MP3. But it luckily supports FLAC and Vorbis (which weren't listed in the specs) so I have some FLACs and OGGs on it as well. It also lacks speed adjustment so I had to pree-upspeed books with Audacity during the days when first Android devices were a luxury thing. If only it had support for OPUS, pitch-preserving speed adjustment and position persistance it could indeed make a great audiobook/podcast listening device.