The "B-roll" video is a supplementary shot that is added to the end of the original shot, then it will be cut into the final video product, which usually includes voice over. After the completion of the video production most B-roll lens will be abandoned, but sometimes the director that captures the interesting things may as a complete video footage publicly. Today on the ninth channel, Microsoft announced a number of interesting things encountered in the process of shooting HoloLens video, and revealed the potential use of this augmented reality devices in the future.
Wrote in the video description: "this section of video footage uploaded to media enthusiasts, this has spread quality footage on the display of HoloLens. Microsoft's HoloLens is the world's first completely unrestricted holographic computer, driven by the Windows 10 system, to be able to project in real life with a high clear holographic objects."