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Updated: 05/12/2008 Part II
World TelevisionStandards andHDTV
Although consumers were at first slow to make an investment in HDTV receivers, by 2006 the move was well underway. Sports programming was a major driving force. Just seeing the difference between SDTV and HDTV images in large measure propelled the move to high-definition.
When projected on a 16 x 9-foot screen and
observed from normal viewing distance, the picture detail in good HDTV systems
appears to equal that attained by projected 35mm motion
picture film. The enlarged illustrations on the left show the relative pixel detail of SDTV and HDTV. (The illustrations assume a 40-inch TV screen.) SDTV produces an image with about 200,000 pixel (picture) points. HDTV increases that by a factor of about 10 to two million pixels.
The difference, of course, centers in the number of (visible) scanning lines, which here ranges from SDTV's 480 lines to HDTV's 1,080 lines. The "pure" 1080p system (as opposed to the compromised hybrid system) delivers the maximum picture detail approved for broadcast. Although this approach is technically demanding, video recorded in this process is so sharp it can be converted to film and projected in a theater without most patrons realizing they're seeing video.
We discuss the relative
advantages of film and video and the differences between their quality
and costs in more detail Converting Wide-Screen Formats
Three approaches are used: First, when the conversion of 16:9 to the narrower 4:3 cuts off the sides of the picture. We refer to this as an edge crop or 4:3 center cut. If we shoot the original HDTV/DTV (or wide-screen film) with the narrower 4:3 cutoff area in mind, losing the information at the sides of the picture should not be an issue. (This is the area on each side of the red box in the photo below, which, as noted, is referred to as a center-cut of the full 16:9 raster.) We refer to the procedure of
keeping essential subject matter out of the cutoff areas as shoot-and-protect. Second, the entire production can go through a process called pan-and-scan. In this case a technician reviews every scene and programs a computer-controlled imaging device to electronically pan the 4:3 window back and forth over the larger, wide-screen format. The red arrows suggest this panning movement. In this picture, cutting off the sides would not be an issue; but what if you had the two parrots talking (??) to each other from the far sides of the screen?
In this case, a letterbox approach can be used, as shown here. But you can see the problem. The result is blank areas at the top and bottom of the frame. Often, we reserve the letterbox approach for the opening titles and closing credits of a production, while pan-and-scan is used for the remainder. Since some directors feel that pan-and-scan introduces pans that are artificial and not motivated by the action (nor the composition they originally intended). They may try to insist their work be displayed using letterbox conversion. Originally, producers feared that audiences would object to the black areas at the top and bottom of the letterbox frame. (More than one person who rented a film (video) in the letterbox format brought it back to the video store complaining that something was wrong with the tape.) Today, however, viewers accept this format.
The effect is especially noticeable when people are part of the scene -- people who, as a result, suddenly become rather thin. (Not that all actors would complain!) Compare the two images above. Note how the bird in the squeezed 4:3 ratio on the right seems to be thinner than the bird on the left. Another way of visualizing the major SDTV-to-HDTV
and HDTV-to-SDTV conversion approaches is illustrated SDTV to HDTV In-Set Conversion Approaches
Clearly, all these approaches leave something to be desired, so today savvy producers originate productions in the 16:9 wide-screen format using the "shoot-and-protect" approach we've discussed.
Digital Cinema
Satellite facilities distributed the video version to digitally equipped theaters, which used high-definition video projectors. The difference between the film and video versions was difficult for audiences to discern. Since 2000, there have been major improvements in the process. By 2007, the images from the best video projectors were sharper than those of 35mm film projectors. Film crews shot Star Wars: Attack of the Clones -- which more than 90 theatres around the world projected in its digital form -- entirely on 24p video (which we covered earlier). Whereas film and processing would have cost several million dollars, the cost of videotape for this production was only about $15,000.
Why don't theaters junk their 35mm projectors and switch to video projectors? It's a matter of cost. They already have film projectors, and for the most part see no need to invest thousands of dollars to convert to video -- especially when audiences probably won't notice the difference. A major step toward video projection in theaters was taken with the release of the 3-D motion picture, Beowulf . The "film" was also seen as representing a major step forward in digital animation. Despite the limited number of theaters equipped with 3-D video projectors and the fact that patrons had to wear special glasses, Beowulf toped the box office when it was released in late 2007.
Each year, the motion picture industry spends almost a billion dollars duplicating films and distributing them to theaters around the U.S. and the world. Films have limited life; they collect dirt and scratches and soon must be replaced. Video can cut the billion-dollar figure to a fraction of this amount by using a central satellite location to uplink theatrical releases to theaters as they're needed. Plus, pirating
(creating and selling illegal copies) is a constant problem,
costing the motion picture industry billions of dollars in lost
revenue.
Pirating feature films is far more difficult when they're encrypted
and either sent directly to theaters via satellite, or, more commonly, delivered to theaters on a high-capacity disk drive or a recording medium such as videotape. We discuss the issue of
pirating in more detail
We can immediately play back and evaluate a scene we shoot in video -- even while the actors and production personnel are still in position. With film the hours of delay involved in processing and preparing film "rushes" (rough prints for quick screening) make this impossible. Today, most film directors use video assist, or shooting on film and simultaneously viewing and recording scenes on video. This means they can play back and evaluate their work as they go along. Finally, not only are postproduction costs far less with video, but special effects are much more easily and inexpensively produced.
Digital theaters can operate with fewer employees, representing a considerable cost savings over time. Offsetting this savings, however, is the initial investment for digital projectors and the associated computer -- an estimated $60,000 to $120,000 per theater screen. It hasn't helped that with the introduction high-definition video disks for the home (primarily Blu-ray) theater attendance has taken a hit. Also hurting theater attendance are complaints related noisy patrons, cell phones ringing, the showing of commercials before films in some theaters -- not to mention the cost of gasoline to get to theaters. You can find information on film revenues, top
grossing films and the future of motion pictures For a more detailed look at the
various DTV and high-definition standards in the United States,
including those for digital cinema
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The 2004-2005 broadcast season was the
first one in which the major networks broadcast live programming
in high-definition television. 
progressive (p) approaches to
scanning result in a significant difference in apparent picture
sharpness (measured in terms of discerned pixel points of detail).
When we compare film and video
media in a broadcast application, the differences between video
and film are based more on differences in their traditional 
panning-and-scanning will not work.
