Frames & Fields (Pt.2)

When TV was introduced into the home, it was (and still is) mostly paid for by advertisers. Ads started simply on the stage, read by one of the performers. The very first produced television ad appeared on July 1, 1941 during a baseball game on a local New York channel. The 10-second ad advertised Bulova watches and cost a mere four dollars! Ads are sprinkled throughout shows at pre-determined breakpoints. There is usually a “stay tuned for” or “don’t go away” outro reminding us to stay on that channel after the advert. In order to keep shows falling into the correct time slots the 30fps standard would require a slight teak. The introduction of drop frame timecode (DFTC) was used to correct this time-of-day drift over a 24 hour period. Drop frame does not removed any frames from the video. It only adjusts the frame rate in the timecode counter. It’s like leap year for timecode. Instead of the counter reading 30fps it reads 29.97fps which is .03fps slower than the nearest whole number frame rate of 30fps. Remember that the timecode reader is not meant to keep time but rather represent a unique identifier for each frame of video for editing purposes. By the time a video has been transcoded for the Web, it looses it’s timecode and most video players only present a counter representing hours : minutes : seconds. Because of this, it is only an approximation to read the time on an embedded Web player and try to match it up with the original video clip’s time code. If you need to create a Web clip to share with producers for editing purposes, it’s common practice to burn-in time code on the video. However, burned-in TC should never be used in a final version.


Now I’m going to talk about conversions. There are times when video will need to be converted to a different frame rate by a post house. This could be needed if the piece originated in a different resolution or needs to be converted to a different country standard. Though it is possible to use software based editors and convertors to make a conversion, the resulting output will be subpar compared to using hardware solutions from Black Magic Design’s Teranex or Snell & Wilcox Alchemist Ph.C. They allow for very high quality de-interlace, up conversion, down conversion, SD and HD cross conversion, SD and HD standards conversion, automatic cadence detection and removal even with edited content, noise reduction, adjustable scaling, aspect ratio conversion and smart aspect ratio 4:3 to 16:9 conversion. Trying to accomplish these conversions in software can result in dropped frames (producing jumpy motion), duplicated frames and motion blurring to compensate these shortcomings. Please explore the following video examples to see how conversions can go wrong…


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