Download of Vidrio 1.23 for Mac was available from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. We recommend checking the downloaded files with any free antivirus. The actual developer of this free Mac application is James Fisher. The application lies within System Tools, more precisely Device Assistants.
From the developer:
Vidrio puts your webcam stream behind your windows. When you share or record your screen, your holographic screen floats between you and your audience. You gesture with your hand, and their heads follow. Vidrio makes screen sharing effortlessly engaging.
You may want to check out more Mac applications, such as ImTOO iPhone Transfer, Fire or DSLRRemotePro, which might be related to Vidrio.