Many video production company setup many studio and webstudio to produce various content for the purpose of TV production or internet TV. In order to do they green screen technology that we see many from the blockbuster movie to news and daily weather predictions over the TVs.
With these green screen technologies it allows a scene to happen inside of a completely different location from a news table setup to outdoor scene. They can make any kind of effects and have been use to create really popular TV series.
Basically the video shooting is done with a large green screen background. A second image which usually a surrounding scene is then takes over the green environment during the editing process. The green background is changed to the images so that the readers will see another setting.
Studio lighting is important here to get rid of the shadows. Compact Fluorescent lighting and tungsten Fresnel spotlight is usually implement in the studio for key light and back light effectively.
Spacing between the object and the green screen is also important. The closer the subject to the background green the heavier the potential for the green spill. Good software and video effects system like Tricaster is also important in keying the process.