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johnmeyer · 21st September 2015, 16:31

There is absolutely nothing evil or wrong about interlacing. It works great, and has been in use for longer than most people on this planet have been alive. It is still used today, and you watch interlaced TV all the time, and it looks wonderful.

That said, it does require more skill and knowledge to work with in the digital realm. In particular, any resizing or change in cadence does require deinterlacing, a step that always degrades the video. But, since re-sizing and frame rate changes ALSO degrade the video, deinterlacing, when used for those operations, isn't necessarily an "evil" thing. (I would advise never to deinterlace for any other reason.)

However, I will agree that interlacing appears to be a bad thing since so many people screw up their video because they don't understand how to handle it properly. This forum is filled with hundreds of posts that perfectly illustrate this point.

As for your request, the answer will depend on what you are trying to do. If you are trying to put it on a DVD, there are some pretty nifty solutions that have been posted in this forum which involve creating some unique pulldown flags. I didn't even know such a thing existed until I "went to school" in this long thread:

How to de-interlace 25i coming from 8 mm film transfer

Despite the heading, this person wanted to do something very similar to what you are doing. I linked to the post in that thread where I learned something I didn't know, namely that you can use something called DGPulldown to accomplish this feat, without any re-encoding. The result will play on an NTSC DVD player. Some people don't like the solution because it is interlaced (see my comments above) and also because they don't like the effect of pulldown (repeated fields). However, having tried all the other alternatives to pulldown, and since I deal with film transfers every day of my life, it is my opinion that this gives you the best-looking, sharpest results, and without any problems that you get doing speed changes or de-interlacing using motion estimation, bobbing, etc.

21st September 2015, 16:31	#4 \| Link
johnmeyer Registered User Join Date: Feb 2002 Location: California Posts: 2,695	There is absolutely nothing evil or wrong about interlacing. It works great, and has been in use for longer than most people on this planet have been alive. It is still used today, and you watch interlaced TV all the time, and it looks wonderful. That said, it does require more skill and knowledge to work with in the digital realm. In particular, any resizing or change in cadence does require deinterlacing, a step that always degrades the video. But, since re-sizing and frame rate changes ALSO degrade the video, deinterlacing, when used for those operations, isn't necessarily an "evil" thing. (I would advise never to deinterlace for any other reason.) However, I will agree that interlacing appears to be a bad thing since so many people screw up their video because they don't understand how to handle it properly. This forum is filled with hundreds of posts that perfectly illustrate this point. As for your request, the answer will depend on what you are trying to do. If you are trying to put it on a DVD, there are some pretty nifty solutions that have been posted in this forum which involve creating some unique pulldown flags. I didn't even know such a thing existed until I "went to school" in this long thread: How to de-interlace 25i coming from 8 mm film transfer Despite the heading, this person wanted to do something very similar to what you are doing. I linked to the post in that thread where I learned something I didn't know, namely that you can use something called DGPulldown to accomplish this feat, without any re-encoding. The result will play on an NTSC DVD player. Some people don't like the solution because it is interlaced (see my comments above) and also because they don't like the effect of pulldown (repeated fields). However, having tried all the other alternatives to pulldown, and since I deal with film transfers every day of my life, it is my opinion that this gives you the best-looking, sharpest results, and without any problems that you get doing speed changes or de-interlacing using motion estimation, bobbing, etc.