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Transitional TV Growing PainsThe transition from analog to digital, SD to HD, 4:3 to 16:9 is going to be a bumpy one
Anyone in the broadcast industry knows that we are in the middle of a transition. More precisely, we are in the middle of multiple transitions from analog broadcasts to digital, from standard definition to high definition, and from standard 4:3 aspect ratios to 16:9 widescreen aspect ratios. Sales of up/down/cross converters are at an all-time high as post houses and broadcasters attempt to get the most out of their HD equipment investments. You can hardly blame them. No one wants to cut the same material twice once for HD and a second time for SD. Its just easier to do everything in HD and then downconvert to SD (or upconvert SD to HD).
The film industry is facing similar transitions as DI (digital intermediate) facilities and emerging digital cinema installations grow in popularity. A typical post house may have to deal with multiple resolutions from SD for DVDs, HD for TV, 2K for digital cinema, 4K for archiving, and finally there is good old film. But they are also facing another trend in filmmaking, the transition to digital video cameras that mimic traditional film cameras. These new cameras can provide filmmakers with features such as under- and over-cranking, 24 or 30 frame per second recording, and even digitally simulating widescreen lenses. Now a filmmaker can shoot with a digital video camera, send it to a post house and have film prints made that are ready for theaters. And its not uncommon for filmmakers to mix video, film, and computer graphics in the same production.
Broadcasters, cable, and satellite companies are also having to upconvert a lot of legacy SD content for their HD feeds. What all this means is that there is a lot of squishing and stretching going on. And every time that happens we lose a little image quality.
I can imagine a scenario where a car company wants to make a commercial. It is originally shot on film in 4:3. After the film portions are shot they are printed, scanned at 2K, color corrected, text and graphics added and then, for visual effect, the finished commercial is letterboxed. After theyve gone through all that they generate an analog SD version to be put on tape and mailed to various TV stations for broadcast.
Meanwhile an independent filmmaker shoots a documentary using a digital video camera using the cameras built-in widescreen mode. The tape gets sent to a post house where it is upconverted to film resolutions for a theatrical release and also converted to a 2K version for a digital cinema release. It has a popular run in the theaters and so it is downconverted from the 2K file to a letterboxed SD video format for DVD release and then a pan-and-scan version for SD television and also a 1080i HD version (not to mention a cross-conversion for European television formats). When it comes time for the HD television premier the broadcaster, who has decided on 720p as their HD format of choice, has to digitize the commercial and up-res it to 720p before inserting it into the HD stream. They also have to convert the film from 1080i to 720p. The show is picked up by satellite and cable companies (who compress the signal before transmission). But the cable and satellite companies transmit their HD signals in 1080i so they also have to convert the broadcast feed again. And not only do they send the compressed HD stream to their HD subscribers they also have to downconvert the signal to SD for all their SD subscribers.
These days, even if you shoot in HD, post in HD, and broadcast in HD the odds are that there are one or two conversions and compressions coming down the line that you have no control over.
Another issue with all these conversions is the overall reduction of quality for the HD cable/satellite subscriber (and even SD subscribers). Since the conversion to all digital, all HD, all 16:9 hasnt happened yet, HD broadcasts are comprised of multiple resolution sources some original HD (that may or may not have been up or down converted), other HD material (from commercials, bumpers, network graphics, etc.), and up-converted SD materials (commercials, and other legacy content). But even if the bulk of the programming was shot in HD to begin with, HD cameras have gone through a number of evolutions even in their short history with noticeable variations in quality. The home viewer has no way of knowing if the HD content they are watching was upconverted, downconverted, or compressed to oblivion. The end result is a viewer experience that fluctuates from mediocre to good to great to so-so and back again from one moment to the next.
All of these up-/down-/cross-conversions and extra layers of compression also contribute to the ever growing problem of loss of audio/video synchronization. Manufacturers of converters and compression devices are fond of touting their devices as operating in ?real-time when in fact they dont (think about it folks, a process such as converting a signal from one resolution to another must take some time it cant be done instantaneously no matter how fast the hardware is!) This slight delay might be negligible in a lab test but even if the process introduces a tenth of a second audio/video time delay those delays will accumulate as broadcasters, local affiliates, cable and satellite companies all perform multiple conversions.
The final bump in the transition road is the move toward widescreen, 16:9 formatted content. For nearly 50 years Hollywood produced movies in a standard 4:3 aspect ratio. It wasnt until 20 years after television was introduced (using the same 4:3 aspect ratio) that moviemakers invented widescreen formats specifically to make their content incompatible with television broadcasts (and thus, hopefully forcing audiences back to the theaters). Over the next 50 years audiences came to associate widescreen images with big-budget theatrical films a perception that HD broadcasters and HDTV set manufacturers wish to capitalize on. But transmitting an HD broadcast in a 16:9 format introduces a whole new set of conversion issues. How do you reformat a 4:3 source so that it fits a 16:9 screen? Do you simply stretch the image horizontally or do you put black bars on either side of the image? Neither solution is very pretty.
On top of that, the television advertising industry has also snatched up the idea that widescreen (specifically letterboxed) images imply ?film-quality production values and by letterboxing a commercial it will impart some of that ?high-quality to their clients products. So even though television commercials were never intended for theatrical release and there is no legitimate reason for them to letterbox a commercial other than pure aesthetics or to try and capitalize on any psychological boosts they might get, the majority of commercials broadcast these days are presented in letterboxed formats. Of course, no self-respecting ad agency creative team could let all that prime screen real estate to go to waste and that has led to a proliferation of letterboxing gimmicks. Spend a few minutes watching a standard television broadcast and pay attention to how different commercials play with letterboxing. Some start out letterboxed then switch to 4:3 and back again. Some put text in the black bars. Some use different colored black bars. Some push the letterbox to the top or bottom of the screen. And on and on. During one evening I counted over 18 different types of letterboxing and Im sure that some ad agency is working on new variations at this very moment.
So now broadcasters have to deal with multiple problems. They have to convert analog to digital. They have to convert between different HD resolutions. Some of the HD content is better or worse depending on the equipment used to capture it in the first place. Some of that content has already gone through multiple conversions before they even get it. They have to convert SD material to HD. Some of the SD content is letterboxed (in no consistent manner) and some isnt. And even if they use state-of-the-art equipment and have done everything perfectly, with as little image degradation as possible, the cable and satellite companies are simply going to convert it again to a different HD resolution or down to SD and compress the hell out of it before sending it out to subscribers.
And we wonder why the transition to HD has been a rocky one.
No doubt things will improve in the coming years. Analog will be replaced by digital. Equipment will get better at converting resolutions. Source materials will improve in both quality and consistency. Advertisers will eventually offer their commercials in appropriate resolutions (and broadcasters will accommodate those resolutions). Sooner or later everyone will have an HDTV widescreen set and ad agencies will have to figure out a different visual gimmick other than letterboxing.
Guy Wright has been kicking around computers and video for more years than he cares to admit and written too many articles to count. He has been a director, editor, producer, video operator, and announcer for a score of radio and TV stations. His credits include hundreds of insipid local-origination programs and commercials, dozens of cheesy radio spots, and even a book or two. Mainly he writes and edits articles for Digital Media Online.
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