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Deinterlacing with FPGA for HDTVs

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Rick M
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re: Deinterlacing with FPGA for HDTVs
Rick M   10/2/2009 1:48:50 PM
Brad, Interlace and De-interlace are common broadcast industry terminology for better or for worse. Analog TV (which no longer exists) broadcast content in interlaced mode - that is, two (2) fields, each at 1/30 sec, to form 1/60 full frames. They needed to do this due to restrictions with regard to RF channel bandwidth allocation. The other thing I think that you are missing is that there is a difference between fields and frames. Fields are only discussed with respected to "i" formats such as 1080i, 480i, etc. "i" or "interlaced" formats always require more than one "field" of data to complete a single "frame" or whole picture. "p" or "progressive" formats such as 1080p (current HD standard), or 720p, or 480p show "frames" at 1/60 sec. This was accomplished solely due to the fact that our new broadcast system (which is really 1080i not 1080p) can accommodate the required bandwidth because of digital compression and transmission techniques. Each "frame" is a whole picture. Therefore, when someone in broadcast or video talks about interlaced, they mean the old "i" format. To de-interlace, you are essentially changing it from the old "i" format to the newer "p" or "progressive" format. I hope that this helps.

K1200LT Rider
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re: Deinterlacing with FPGA for HDTVs
K1200LT Rider   7/23/2009 11:59:17 AM
For the following text from the 5th paragraph: > Deinterlacing Background > In interlaced video one frame of video > is broken into two fields ... I get confused on how the words "interlacing" and "deinterlacing" are used. When you say you take video data from 2 fields and put it together, you are calling that deinterlacing. I say it is just the opposite. The definition of interlace is "to put together" which is what is being done to the data. I believe that the problem comes in because there are 2 separate contexts in which the term (de)interlace is used. The term "interlaced" in the 1st sentence in the 5th paragraph is referring to the video format, but later in the same paragraph it says that "... the display must be deinterlaced." I think it should say that "... the video data must be interlaced together to create a non-interlaced/deinterlaced format." In other words, the format changes to "deinterlaced" after an "interlacing function" rearranges the video data by *putting it together*. Format vs. verb/action. Am I backwards in my thinking? If so, I have named some of my video manipulation functions exactly opposite of what they should be. Even if I am "wrong," I'm not going to rename them because it would only lead to confusion. - Brad

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