AV Foundation Capture is the default pref­er­ence for Capture. AV Foundation cap­ture is a cap­ture option which allows the user to achieve com­pres­sion on the fly but still free up the CPU for oth­er tasks.

You will recog­nise the AV Foundation cap­ture win­dow by the Floating tool­bar and the absence of a pan­el at the base of the win­dow con­tain­ing cap­ture set­tings. In AV Foundation cap­ture these set­tings are con­tained in the Inspector which is accessed by click­ing the but­ton in the
float­ing toolbar.