I'm in the middle of a similar project but using a mirrorless camera with a macro lens and a repro stand.
I second most of this, but would like to offer a different opinion about triage. In my experience, doing the triage often takes as much time as digitizing the slides. "Mindless" mass digitization where I just optimize for throughput has been a good strategy for the collections I've worked on.
Instead I'm more careful of what I choose to post process after I digitization. I haven't been throwing much away yet, I usually just don't process the stuff I don't find interesting. Storage is cheap these days.
Our wowza streaming servers are hosted in-house, and are integrated with our authentication software. I don't know the nitty gritty details about the solution though, access is outside of my domain
This is correct. The mp3 is a an access file sitting on our streaming servers (wowza), outside of the preservation environment. The old access files were of very low quality, so new m4a/aac files were created.
In the cases where we only had mp3 files, the mp3 file was preserved as our master in the preservation environment, with a copy sent to the streaming servers.
The re-archiving process was mainly a data migration. However, there is an initiative to use the in-house developed NB-whisper model [1] (based on OpenAIs Whisper) to do speech recognition/transcription.