Thanks for your kind words and welcome to the Doom9 forums, fszecsei.
__ENCODE_3D_LAUNCHER.cmd and blocksleep.exe have been added when I have received complains of some users about encoding problems. Blockssleep has been written by Slavanap and officially released
here. As you can see, it is open source.
As its name suggests, blocksleep.exe is used to prevent Windows from going to sleep mode during an encoding. It is used by __ENCODE_3D_LAUNCHER.cmd to launch __ENCODE_3D.cmd. It doesn't do anything by itself. It just sets a flag telling the system to not go to sleep mode while __ENCODE_3D.cmd is running. Without that, most laptops and some desktop PCs go normally to sleep mode after some time, and of course the encoding stops. It has also been reported several times that x264 has often some trouble to continue the encoding when the laptop wakes up, and that can result in a damaged or incomplete video stream.
I don't know why Norton considers blocksleep as dangerous. Perhaps it's because it is designed to launch other exes or batch files? Anyway, it's a false positive. You can even delete it if you wish, and launch __ENCODE_3D.cmd directly, if your PC uses a power plan with sleep mode disabled, or if you accept to take the risk of a bad encoding. (Note that __ENCODE_3D_LAUNCHER changes also the priority of the _ENCODE_3D process to low, so that you can still use your PC to do other things with a reasonable speed when the encoding is in progress, but it's not absolutely necessary.)
Finally, as an evidence that blocksleep is harmless, have a look at its
VirusTotal report. It has a score of 1/63, and only Cylance (an obscure antivirus) flags it as unsafe (and unsafe doesn't mean infected).