Lossless analog capture on macOS
 

It turns out that the software (VideoGlide) that was bundled with the Diamond VC500 mac dongles we have can use installed quicktime codecs, which includes the UT Video lossless codec. (I'm not aware of huffyuv, lagarith or FFV1 for macOS outside of ffmpeg.)

The software does include proc amp settings and a histogram (and vectorscope view), though I couldn't see any frame drop count.

While using virtualdub on windows is the preferred method, this is at least an option for someone stuck with macOS without resorting to DV over firewire with it's drawbacks.

The VC500 mac version does not use the same conexant chip as the "normal" VC500. One of the two we got has a Trident SAA7113 video encoder, combined with the standard empia 28xx usb bridge and sound chip. I believe the SAA7113 is decent-ish, it's found on a bunch of older USB cards and some Nvidia VIVO graphics cards, and I believe it's related to the SAA7114 that's found in the Cypress/AVT/TVOne TBC among other things but less advanced. The other one has a single empia 2980 chip, which I can find almost no info about on the net. Though, I found that the magix usb dongle we had had the exact same chip. Don't know what video decoder is built into it. The VideoGlide website claims that it works with a number of empia based dongles, so there may be other dongles out there that can be used, though as they are empia based, aka what EZCap and clones use, the quality may vary.