Extending the number of object classes

[binarybehemoth]

I used Visual Studio to build darknet.exe. So how many object classes can be detected with the pre-trained models?

I wish to extend the number of recognizable object classes. Would you recommend me to train with Google Open Images? Will the detection process be too slow if I extend them to 1000 classes. Has someone already done that for us, ie. free YoloV4 models?

Also, why hasn't the yolov4.weights file been included here? I had to download it elsewhere.