RTSP example to read IP camera using Qt 5.15. Works with Android using ffmpeg_android_maker, Linux and Windows. May need to copy DLLs from Windows ffmpeg bin folder to app folder.
Works with Windows with ffmpeg from https://ffmpeg.zeranoe.com/builds/ and ffmpeg in Linux.
https://github.com/Javernaut/ffmpeg-android-maker
Edit QtRTSP.json file to add up to 6 RTSP streams. App likely crashes if stream not available. QtRTSP.json likely found in ~/.local/QtRTSP in Linux, c:\users{user}\Appdata\Local\QtRTSP in Windows and {root}/QtRTSP folder in Android. A default file is written if QtRTSP.json is not found.