ReadyDLNA/MiniDLNA/UPNPAV/ReadyMedia Problems

Thanks again, StephenB, you're advice is always much appreciated, in this thread as in many others I only read. I understand that these problems are fairly common, but I'm pretty familiar with media file formats, which is why this thing which has puzzled me for years is so frustrating.

One clarification to my earlier post, is that the video files which in the DLNA clients show up as audio-only appear to be the same ones for which minidlna spits out that error message. That may be a hint, but it hasn't helped me yet.

As for your suggestions:
(a) MediaInfo on all the files doesn't show me any hint of why they don't work.
(b) I'm using Plex on some devices and that--while it has problems of its own--is fine for those devices.
(c) In the past, I've tried remuxing them as mp4s again with mp4box, without success. I could try mkv, but a bunch of my players only do mp4s.
(d) Will do. My hope is that somebody at ReadyNAS who is working on the updated minidlna will have some insight, based on the source filename and line number in the minidlna error message.

Thanks again!