[FFmpeg-user] Mystery container

[asdffdsa417 at yahoo.co.uk]

TL;DR: I want to extract an H.264 stream from a stream not recognised by FFprobe, and thought someone on here might have some experience doing this and be willing to suggest what to look into.

I have a DVTEL encoder which claims to use H.264/AVC. It comes with proprietary decoding software but I want to use FFmpeg. However, the UDP stream that it produces isn't recognised by ffprobe. (Unlike a test UDP stream from VLC, which works fine.)
I'm guessing it's some kind of proprietary container, but I'm hoping that there will be H.264 NAL units that I can parse out with my own code, given that it does use H.264.

Interestingly, parsing the data for the 0x000001 start code and recording the distance in bytes between occurrences shows that the gaps come in three kinds of sizes: large (c. 25kB), small (c. 7kB) and tiny.
However, parsing the nal_unit_type that follows this code yields fairly random looking results (assuming it's being parsed correctly).
Just wondered whether this seems feasible and what I might be doing wrong.

-------------------------------------------------------------------------Procedure for capturing the stream:
* start wireshark capture
* start VLC UDP stream -OR- DVTEL encoder stream (by going to a web page on the device which runs an ActiveX program...)* filter out the relevant UDP packets (one side of the conversation only)* save the data in binary format* ffprobe data.dat (or ffplay)
result: if VLC, then sensible output indicating mpegts, H.264. If DVTEL encoder, a warning about a format detection score of 1 followed by warnings and failure.