Just a quick update on the above - apparently the VP09 format (also known as VP9) is more highly compressed than e.g. normal .mp4 (it still presents as .mp4 but the latter is basically a container so can have different things inside), and the latest VLC media player version does support it - I downloaded that and can confirm (previous versions were also *supposed* to support it but perhaps not every wrinkle of it, who knows...).

As an alternative I also successfully used a free video trancoder (VSDC free video editor) to produce a version in a different format ("normal" .mp4 is one option, but I used .avi which normally gives a more compact result) which VLC media player was happier with - I tried that and it worked as well, only proviso being that the result was a larger file, 1 GB (.avi) instead of 250 MB or so (.mp4/VP9) i.e. a 4x size increase.

In any case, 2 methods to produce a VLC-playable file, both worked.

- Tony