How many concurrent streams can the Raspberry Pi 4 support? The Channels Raspberry Pi page says "Fully supports hardware transcoding of up to 1 stream for remote viewing. Transcoding is not required when watching at home."
So how many streams will it handle when it is not having to transcode?
That is limited only by your disk and network speeds. With a USB3 drive I'd say atleast 4 and probably closer to 8.
I agree. The Pi chugs along even at 6+, but load numbers climb to where you would at least thinking about worrying about it.
Transcoding, on the other hand.... 
Great! I won't have more than 3 going at the same time. It is really cool that I have been running my DVR for a year on a Raspberry Pi. Thanks for creating the Pi image.