So, a while ago I wrote an FFmpeg progress script. It worked, but it wasn’t brilliant and it fell apart on occassion.
After getting so annoyed by trying to get it work, I gave up. However, having a need to encode some stuff with FFmpeg again, I decided to return to the script. In the interveening period, my post on the Ubuntu forums, apart from getting one of the best response ever (see the matrix comment) had also encouraged others to give their solutions.
I thus used a combination of these ideas to create my updated version, which is below. It seems to be slightly more robust and still give the same useful info. I will be using this version for now, so I hope it is of use for others
YAFF by Rupert Plumridge is licensed under a Creative Commons Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales License