The camera app on the Galaxy S7 and Galaxy S7 edge comes with Pro mode, a feature that is already available on the Galaxy S6 and Galaxy S6 edge. However, the advantage on the new devices is that the feature works even when video recording is active. Yes, you can change certain settings manually while recording a video.
Once you activate the Pro Mode in the camera app (Galaxy S7 or Galaxy S7 edge), you can change the focus point and white balance on the fly as the video is recording. As for ISO, aperture and exposure values, those still need to be set before you start video recording. Moreover, there's a provision to apply live filters to a video. Keep in mind though that you won't be able to change the exposure value after setting a custom aperture value.
Neither the Galaxy S6 nor the Galaxy Note 5 have this feature despite getting the Android 6.0 update. However, the Pro Mode for video on the Galaxy S7 still isn't as advanced as the one found on the LG V10, which even lets you change the direction for audio recording. Have you tried the Pro Mode for recording videos on your Galaxy S7 or S7 edge?