Doc1997

The uploader for that channel do have access to a cabin that has an external device to capture direct game footage (usually labeled as 録画台 - there are a few arcade venues in Japan that has them). Furthermore, if you scroll down, you can see a few videos that has 暫定版 at the beginning of the title. Those are the temporary versions because there were no cabins at the time that can capture game footage directly, so they have to resort to record the actual screen. So no, I don't think this is captured directly from a PC.

Yeah, most likely they do now have access to a cabin that actually has an external video capture device. Previously, there aren't any, so only choice was to capture the actual screen instead.