encode video

Can someone explain what the differences are for the Hardware encode (under camera options/video) and the Hardware acceleration (under camera options/record/encoder options)? I have kept my video compression set to direct-to-disk but was wondering now that I'm using a dedicated NVIDIA card for...

How can I change the stream level from main profile that is the default output profile from h264 codec in psdatacall demo to baseline that is the profile I needed for transmit between c++ and python in my application