DPC video add-on (optional)
Without it the app still makes all listing pictures and a small GIF. With it, it also makes an MP4 slideshow
(1920x960 = 2:1, 12 seconds, no sound) that Etsy accepts as a listing video.

Installed app:  double-click INSTALL-ADDON.bat (copies bin\ffmpeg.exe to %APPDATA%\DigitalProductCommander\bin).
Portable app:   copy the "bin" folder into the "data" folder next to Start-Portable.bat.
No restart is needed. It survives app updates. To remove it, delete that bin folder.
