Best ways to stream live video to a webpage using Python/C++/Java
What kind of live video source that you mean? If you don't intend to do this code-wise, you can use the free VLC Player to act as a streaming service in between any kind of media stream source (file, network, capture device, disc) and your web video client.
But, if you intend to do this code-wise, you can you VLCJ library. Other options can be Xuggler or FMJ.
I want to read in a live video stream, like RTSP, run some basic processing on it, and display it on a website.  What are some good ways to do this?  I have used OpenCV for Python before but found it to be a hassle.  I am also familiar with Java and C++ if there are better libraries available.  I haven't done a lot of web development before either.