What Are Your Opinions on Interlaced Scan?

[Deleted User 39627]

This is just a general inquiry asking about how everyone feels about Interlaced Scan as a display signal technique.

The following is my personal opinion on how I feel about Interlaced Scan as a signal display type format.

I'm very thankful that HandBrake does allow you to de-interlace and de-telecine all those artifacts as best as the algorithms can, but in general speaking terms, in my opinion, I personally think Interlaced Scan has far outlived its usefulness as a signal scanning technique because it's an old type of analog signal that really only works well with CRT Television monitors which natively supported Interlaced Scan to begin with since it was integrated into the hardware.

Modern hardware and devices nowadays like Computers, HDTV's, Mobile Devices and Tablets now natively use Progressive Scan as the default signal scanning technique used to render a picture clearly and the problem with that when it comes to working with Interlaced Scanned footage is Interlaced Scan isn't compatible with Native Progressive Scan displays, so displaying an Interlaced Scan video on a Progressive Scan Display will cause combing artifacts and/or 3:2 pulldown (telecine artifacts) to appear, which is very distracting, annoying, and frustrate me to no end.

Which I why I personally have a strong deep hatred for Interlaced Scan because let's be honest here, as a perfectionist wanting to become a Post-Production Engineer, De-Interlacing and De-Telecining those artifacts is a real pain in the ass to remove them perfectly because some "residue" will still be left over as it is mathematically computation intensive, processor intensive, very algorithmically complex and can be very difficult to completely remove these artifacts since no de-interlace and de-telecine filter is perfect (at least not until we ever reach that level if it's even possible).

I'm personally looking forward to the death of Interlaced Scan as a Signal Scanning Technique since I'm still waiting for the majority of Multimedia Industries to abandon support for using Interlaced Scan and completely switch over to only using Progressive Scan since it pretty much has all advantages compared to Interlaced Scan and really the only disadvantage that I can think of for Progressive Scan is that is uses twice the data rate of Interlaced Scan. It's pretty simple, Interlaced Scan is an outdated Analog Signal Type, Progressive Scan is pretty much a Digital Signal Type that is much more integrated with modern devices and technology currently being used around the world.

Interlaced Scan in my opinion should only still be supported on Transcoding software just like HandBrake where you can de-interlace and/or de-telecine those artifacts, but as far as real world applications are considered like video cameras, video game consoles, computers, and HDTV's, it really should be abandoned.

However, on a positive note I will say this, Interlaced Scan definitely was a very useful format back when Analog CRT TV's were still around when it natively supported Interlaced Scan most likely from the 30's to the early 2000's, but now since the Analog CRT Television has been completely phased out in favor of Digital Television especially when we transitioned from SD to HD and so forth, it pretty much has rendered Interlaced Scan a useless format that really has no practical use anymore (except for TV broadcasting studios trying to save bandwidth and money, and of course for using transcoder applications in order to try to remove those artifacts).

I really don't understand why it continues to be used since 2020 is right around the corner. To me, it's really such a problematic format to use since you programmers have to go through all this much trouble, hassle, and effort just to write some solid code or add third party libraries to have a decent de-interlacing / de-telecine filter algorithm just to remove those distracting artifacts, which really can take a very long time to do so. Not to mention that at the hardware level, specialized de-interlacing circuits have to be integrated into all Modern HDTV's or DVR boxes that I assume are very fine tuned for precise signal control.

Interlaced Scan really needs to be abandoned because with the exception of supporting Interlaced Scan for transcoding software, I really don't see any reason why these Industries should continue to support this signal scanning format except for removing these artifacts.

Does anyone agree with my argument on this? I did a ton of research on Interlaced scan, Progressive Scan, and different types of technologies and I personally would like to know your opinions on this.

[Deleted User 13735]

Non-broadcast producers haven't used interlaced since tape acquisition days (early 2000s). It wasn't a choice before then.

Interlaced scan was invented before WWII to save bandwidth.
It still is. I assume that you are in the US, because Japan has had UHD progressive broadcast for years.

You can expect 1080p broadcasting when ATSC 3 goes into effect, "when" is anybody's guess. I understand there are a few test markets planned. We already have 720p broadcasts on ATSC 1.

Your advocacy would be better focused on fewer channels with >6MhZ.

Your next "ton" of research can focus on the standards (the only reason interlaced exists), not the technology, which has been with us for decades.
https://www.atsc.org/newsletter/atsc-3- ... -we-stand/

[Deleted User 39627]

Your points are very well written @musicvid, and yes I am in the U.S. I apologize for being too narrow-minded on my viewpoint. I was venting my frustrations on how difficult Interlaced Scan has been to work at least in the Video Production market (in terms of dealing with interlaced artifacts interfering with the video quality). However, I do completely understand and acknowledge your main points.

I'm just saying that I just hope all these industries finally abandon Interlaced Scan and transition to Progressive Scan at least here in the U.S. because I'm just one of those perfectionists who wants the overall video quality itself to look as clean, detailed, and display high resolution as much as possible without having any video artifacts (excluding compression artifacts) interfering (in order to avoid making it difficult during post-production to "clean" up the overall image so that it doesn't look distracting) for the overall quality to look clean, professional, and clear for everyone when it comes to HD.

That's why I have very strong arguments against industries continuing to use it now in the modern days and why I strongly favor Progressive Scan for all the benefits it really has given us despite it requiring twice the data rate to transmit.

I'll be sure to eventually do more research on ATSC 3, 6 mHz, and of course on the standards so I can further educate myself why we have come so far with these formats. I'm hoping that this new decade will allow us to see further evolutions of these standards so that will be able to better process and encode HD video quality so that post-production can hopefully become much easier to remove artifacts while allowing the video quality to not be harmed too much since that's where my passion lies.

I appreciate you clearing this up, Thanks!

[Deleted User 13735]

Just like REC 709, the interlaced format is grandfathered, and will always be present in some form. We are moving away from it on the internet, and I assume it will stop being broadcast my the major networks at some point after ATSC 3 takes effect. True progressive takes almost twice as much channel bandwidth as interlaced.

[Deleted User 39627]

You don't have to tell me that. I'm quite fully aware that Progressive Scan does require twice the bit rate as well as almost twice the channel bandwidth to transmit, which unfortunately is still the exact reason why major HD broadcasting stations still aren't able to transmit at 1080p at 60 frames per second because that would be very computer processing intensive and would eat up lots of storage. That's why they still stick with 1080i to save money, bandwidth, and processing power since I can't imagine how much of an upgrade overhaul the network departments would have to do to get it set up for high transmit bandwidth requirements.

But to be honest, to me, unless I'm missing something, double data rate and channel bandwidth requirements seems to be the only major disadvantage that Progressive Scan has, whereas picture quality-wise it scans the whole frame for the motion to appear smoother and more realistic, there an absence of visual artifacts associated from Interlaced Scan (such as Interline Twitter, Combing Artifacts, and Telecine) and the only artifacts that Progressive Scan deals with normally would be something more tolerable like Compression Artifacts, which is largely controllable based on your export settings and what post-processing filters you use.

Progressive Scan definitely has way more advantages then disadvantages from what I understand, and once these networks overcomes these challenges of upgrading their storage hardware for it to be 1080p60 compatible, when that eventually happens, things will look much better since we'll finally be moving away from an analog signal to a digital signal transmission.

[Deleted User 39627]

I still don't really understand for stations that aren't able to use 1080p at 60 frames per second, instead of using 1080i, they refuse to just downscale the resolution down to 720p at 60 frames per second so that, despite having a lower resolution, the picture quality and motion will look sharper, smoother and better without requiring any extra processing power to de-interlace the signal. But unfortunately that's up to the stations.

[Deleted User 13735]

I still don't really understand for stations that aren't able to use 1080p at 60 frames per second, instead of using 1080i,

Sir it's just math. 60i is 30 frames. We cannot currently broadcast coherent 108OP at any frame rate in a 6 MhZ channel bandwidth. You cannot fit 10 gallons of water in a 5 gallon bucket.

and once these networks overcomes these challenges of upgrading their storage hardware for it to be 1080p60 compatible

There is no such limitation. 1080 p60 is streamed 24/7/365 all over our world. When the law allows, we will have instant 1080p OTA Broadcast! Circular thinking or scapegoating the stations will not change that.

Until the legal broadcast channel bandwidth of 6MhZ (ATSC1) is changed, that will likely remain the case. I regretably do not know how to explain it any other way.