Portal may refer to:

A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects. The process of filmmaking has developed into an art form and industry.

Films are cultural artifacts created by specific cultures, which reflect those cultures, and, in turn, affect them. Film is considered to be an important art form, a source of popular entertainment and a powerful method for educating – or indoctrinating – citizens. The visual elements of cinema give motion pictures a universal power of communication. Some films have become popular worldwide attractions by using dubbing or subtitles that translate the dialogue into the language of the viewer.

Films are made up of a series of individual images called frames. When these images are shown rapidly in succession, a viewer has the illusion that motion is occurring. The viewer cannot see the flickering between frames due to an effect known as persistence of vision, whereby the eye retains a visual image for a fraction of a second after the source has been removed. Viewers perceive motion due to a psychological effect called beta movement.

Dan Trachtenberg is a filmmaker and video podcast host from the Philadelphia suburbs who currently resides in the Los Angeles metro area. He is one of the three hosts of The Totally Rad Show and a former co-host of Geekdrome. Both programs are hosted at Revision3. In addition to working on Internet shows, Trachtenberg is the writer/director of the 2003 short film Kickin' and the director of various television commercials and public service announcements.

Trachtenberg has directed commercials for Lexus, Nike, and Coca Cola. In April, 2008, he joined Tight Films, for which he collaborated with Matt Wolf on an alternate reality game for Hellboy II: The Golden Army."

He directed the internet show, "Ctrl+Alt+Chicken."

On August 23, 2011, Trachtenberg released the short film, Portal: No Escape. Based on the video game, Portal, the film drew more than one million views within its first day on YouTube.^{[citation needed]} Within two months, the number of viewers surpassed six million.^{[citation needed]}