Virtual Studio is quite common among Television production studios. For common man, daily TV News bulletins or discussion looks highly attractive with the decorative and colorful studio setup. Most of the people are not aware that the building or other creative structure looking behind the Anchor is all virtual. These are just created graphically. It is possible to show a News reader sitting at Taj Mahal and reading the daily bulletin. A discussion can look like as recorded in front of Eiffel tower. Nowadays, most of the News channels are using Virtual Studio for daily News bulletin and current affair discussions.
Why Virtual Studio is required?
Normally physical sets are created for recording television programmes. If some discussion program related to health need a background, then some of the pictures of related matter are printed on cloth or flex material and erected on wooden or iron structure. This is placed at the backside. It creates a background for recording video.
Disadvantage with physical sets – Several programmes are recorded in a single studio so creating a physical structure for each program is not economical as well as not feasible to erect in short interval of time.
Advantage with physical sets – If studio area can be spared for maintaining or creating a physical set for longer duration, mean it need to be disturbed daily, then physical sets may be created. Physical sets are real in nature hence they have higher depth of field. They don’t need much technology for creating background so cheap in short term. Video recordings where large recording area is used, it is a costly affair to create a Virtual Studio for sizeable area.
So Virtual Studios are normally part of News studio where multiple bulletins are there and different discussion programmes are recorded. So a small studio can also be used in different looks for each program and each look or background can be changed in minutes.
Technology involved in Virtual Studio.
Here comes the concept of video background and foreground. In general, normal studio sets are for creating background and other accessories like table, chair, Anchor are foreground of a video.
So here comes the two part of any video. First is foreground and another is the background.
Final recorded video = Foreground video + Background video.
Look at the picture shown below.
Above picture clearly shows how the foreground is superimposed on a background. Now apply same thing for video production. In a still picture, this looks quite simple but video makes it little complicated.
Here look at the foreground picture. It has a blue background that is replaced by background image for creating the final image.
When video is recorded with some single-color background like blue and background is replaced by a still image, the process is called Chroma Keying in Video production. Chroma keying is an old process where a still picture replaces the background of video.
Video is a sequence of images. It changes with time, and changes can be through different aspects of video. If there is zoom-in, then object comes closer, if there is zoom out, then object goes further in the video frame. Therefore, due to camera zoom operations, foreground object looks closer or further in the video frame. Similarly, camera position also changes the video frame so overall two parameters change the video frame. First is the zoom operation and other is the position of the camera in three-dimensional space.
In the old Chroma keying process, in spite of changes in the foreground video due to change in camera position or zoom, background images remain same and still. It clearly gives some impression like a still image pasted on a blue background.
With the development of technology, this Chroma keying process is advanced and now background image also changes in the same fashion as foreground video changes. For example, when camera zooms-in then as foreground video zooms in similarly background image (Graphics) also zooms in the same ratio. So all changes which take place for foreground video, the same changes are applied to background video ( graphics generated through computer) and then foreground and background video are mixed as Chroma keying. This creates a normal studio into Virtual studio.
Foreground video is the final output of multi camera studio setup. Background video is generated by a high end graphics machine in real time. This graphics machine receives space coordinate and zoom position of the camera continuously. The graphics video output changes in the same manner as the coordinates of camera position and zoom changes. So the correlation between foreground video and background video is maintained by a tracking mechanism. Once virtual background is superimposed on foreground video, resultant video makes a Virtual Studio a reality.