Register custom URI scheme handler in Windows 10
you set the "Default Icon" as key, but it should only be a string. This is the only difference i see. Attached a working version of my configuration (do connect rtsp with vlc).
kr stefan
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\rtsp]
"URL Protocol"=""
@="URL:Rtsp Streaming Protocol"
"DefaultIcon"="\"C:\\Program Files (x86)\\VideoLAN\\VLC\\vlc.exe\",1"
[HKEY_CLASSES_ROOT\rtsp\shell]
[HKEY_CLASSES_ROOT\rtsp\shell\open]
[HKEY_CLASSES_ROOT\rtsp\shell\open\command]
@="\"C:\\Program Files (x86)\\VideoLAN\\VLC\\vlc.exe\" \"%1\""