Watching Digital TV on a CRT TV without interlacing

[bigbadben]

I have a Conia CRT TV and an HD digital set top box. As soon as I connect the set top box there is enormous interlacing, especially when you set it to 576i in the settings. 1080i not as much. The box simply downscales the video rather than just setting the resolution. I have tried using a DVD recorder as a pass through to deinterlace it but there is still interlacing, and on top of that there is noise on screen from the DVD recorder in the form of fine grey horizontal lines on screen. I tried connecting a Chromecast with Google TV using an HDMI to AV converter, and there is still interlacing, and there wouldn't be any if you could set the resolution to 576p like before, except since the last update, Google now demands that you set it to at least 720p because 576p and 480p are not supported anymore since the last update, but before the update it was working just fine: https://www.googlenestcommunity.com/t5/Chromecast/Google-TV-does-not-support-720x480-d...on/td-p/286007 Is it possible to watch TV on a CRT TV without interlacing in 2023?

[Skiller]

If you film your screen and upload the video to YouTube we might be able to find the cause.

[dellsam34]

That's the nature of CRT TV, It flickers. If you don't like the flickering get a modern TV, They are obsolete for very good reasons.

[Skiller]

That's too generic.

The flickering does have benefits in some ways, compared to a steady background light, as I'm sure you know.

(Besides we don't know yet if the OP is complaining about flickering or something else.)

[Bwaak]

As soon as I connect the set top box there is enormous interlacing

Interlacing cannot be enormous. It is a scanning technique, so it is either being employed or not. You probably wanted to say "combing". Normally, you should not see combing if you watch interlaced feed on an interlaced TV because this is what interlaced TVs are made for. You can see some flicker, but not noticeable combing. If you see combing, it may be that the original video has been deinterlaced incorrectly, and then it has been re-interlaced and sent on your TV set, or maybe it is being sent as progressive.

In any case, unless you have a 100Hz/120Hz CRT TV, it will flicker and the picture will be more murky.

[bigbadben]

As soon as I connect the set top box there is enormous interlacing

Interlacing cannot be enormous. It is a scanning technique, so it is either being employed or not. You probably wanted to say "combing". Normally, you should not see combing if you watch interlaced feed on an interlaced TV because this is what interlaced TVs are made for. You can see some flicker, but not noticeable combing. If you see combing, it may be that the original video has been deinterlaced incorrectly, and then it has been re-interlaced and sent on your TV set, or maybe it is being sent as progressive.

In any case, unless you have a 100Hz/120Hz CRT TV, it will flicker and the picture will be more murky.

I use the term interlacing maybe incorrectly as I'm not familiar with video terminology. The best way to describe the problem is vibrating on screen. For example if you're watching tennis, the lines on the court vibrate very noticeably. Like instead of the lines being static like they should be they are sort of pulsing on screen. I would post a video but it can only be seen in person.

[bigbadben]

If you film your screen and upload the video to YouTube we might be able to find the cause.

The last time I tried to film it looks normal to a camera. But in person you can definitely notice a problem. I'll see if I can somehow film it. It shows up in some areas and in others not. It especially shows up when there are like lines close together and they start vibrating on screen which is very distracting.

[dellsam34]

Yes that's how CRT TVs are, They never had a stand still background like computer CRT monitors, Yes they are bright, good for interlaced contents but they are not perfect.

[usually_quiet]

As soon as I connect the set top box there is enormous interlacing

Interlacing cannot be enormous. It is a scanning technique, so it is either being employed or not. You probably wanted to say "combing". Normally, you should not see combing if you watch interlaced feed on an interlaced TV because this is what interlaced TVs are made for. You can see some flicker, but not noticeable combing. If you see combing, it may be that the original video has been deinterlaced incorrectly, and then it has been re-interlaced and sent on your TV set, or maybe it is being sent as progressive.

In any case, unless you have a 100Hz/120Hz CRT TV, it will flicker and the picture will be more murky.

I use the term interlacing maybe incorrectly as I'm not familiar with video terminology. The best way to describe the problem is vibrating on screen. For example if you're watching tennis, the lines on the court vibrate very noticeably. Like instead of the lines being static like they should be they are sort of pulsing on screen. I would post a video but it can only be seen in person.

If your CRT TV only has an RF connection (for connecting an antenna) and analog composite video connections (yellow RCA ports) for video input, then trying to create a progressive video signal to feed to your TV is a waste of time. CRT TVs that only have an analog tuner and composite video connections only support standard-definition interlaced video input.

The artifacts you are seeing are common if a set-top box is downscaling from HD to SD for an analog CRT TV. I had the same problems with my analog CRT TVs when the USA shut off SD analog broadcasting, switched entirely to digital broadcasting, and I had to use a converter box to watch TV. I had to endure the annoying artifacts you described until I replaced my CRT TVs with HDTVs. Fortunately, I don't watch a lot of sports.

[Bwaak]

The artifacts you are seeing are common if a set-top box is downscaling from HD to SD for an analog CRT TV. I had the same problems with my analog CRT TVs when the USA shut off SD analog broadcasting, switched entirely to digital broadcasting, and I had to use a converter box to watch TV. I had to endure the annoying artifacts you described until I replaced my CRT TVs with HDTVs. Fortunately, I don't watch a lot of sports.

Insufficient vertical low-pass filtering?

[Skiller]

Insufficient vertical low-pass filtering?

Yes, most likely that's it!
These boxes just downscale the HD frame to SD without applying a vertical low-pass, which is absolutely mandatory for interlaced video to look acceptable on any display device, especially CRTs.

The artifact which arises from insufficient vertical low-pass is called Interline Twitter.