There is a major hardware limitation in many NVIDIA graphics cards. There is a maximum limit of simultaneous video encoders. Usually the limit is 3 encoders but it can vary between 1 and 5 depending on the gpu model. Now that MB STUDIO has many new releases and video encoders, be careful not to exceed the limit of video encoders at the same time. The count also includes any external applications: for example if OBS Broadcast is in use and the GPU supports 3 simultaneous encoders, there are only 2 video encoders left that can be used by MB STUDIO (for example 2 video recordings or 2 simultaneous RTMP encoders).
When the maximum limit of video encoders is exceeded, the encoder may not start or it may start but using the cpu for encoding, thus with a significant increase in CPU load and power consumption.
More advanced users can remove this limit thanks to a patch available here: https://github.com/keylase/nvidia-patch/blob/master/win/README.md
So let's see how to apply the patch that will allow us to have unlimited video encoders:
1) close any video application (MB STUDIO, OBS, VMIX, etc etc)
2) if you haven't already, install the video driver listed here: NVIDIA HANDLES LEAK this procedure will fail if the installed nvidia driver is not exactly 522.30 studio driver
3) download this file https://www.mbradio.it/service/NvidiaPatch.zip and unzip it wherever you want (it's fine on the desktop too, it's a disposable folder)
4) run Win_1337_Apply_Patch.exe
5) at line 1337 file select the file nvencodeapi.1337
and at the next request select the dll c:\windows\syswow64\nvencodeapi.dll
5) click on PATCH
6) now click again on the 1337 file button and select nvencodeapi64.1337
and then c:\windows\system32\nvencodeapi64.dll
and then click PATCH
If both procedures gave success message you can now restart Windows and use unlimited video encoders. Naturally the maximum number of simultaneous video encoders will now depend on the power of your Nvidia GPU which you can monitor from "Task Manager".
In MB STUDIO \ Configuration \ Webcast \ More ... you have to set the gpu to Nvidia
If instead you have had errors it is probable that the nvidia driver is not 522.30 studio driver or there is a video application left open (OBS, VMIX, MB STUDIO, etc, etc). Restart Windows and try again