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How do you deal with blurry Hazy graphics in an old CRT TV purchased in the last 15 years? (discuss.tchncs.de)

submitted 1 year ago by [email protected] to c/[email protected]

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About TV

Company: Daewoo DC

Purchase date: Last 15 years, and the most modern of its time

Size: 24 inch

Interface: Has Audio-Video port

[Other than that, its just a radioactive box, weird signal goes in, video comes out]

About Raspberry pi

Model: Raspberry Pi 4B (4GB RAM)

OS: Raspberrypi OS

Situation

Its not cabling thats the issue. The TV shows visual but the graphics is very hazy and blurry. I suppose it has something to do with either the frame rate made for digital monitors being too high for the TV or the video resolution being too unbarable.

I have used CRT computer monitors but they used VGA. In those monitors, I used to set resolution to 800x600px and it would show the clearest. CRT monitors dont have this concept of pixels, yet setting pixels to 800x600 does the job in VGA CRT monitors. It did not work in case of my TV.

I should mention that the device I purchased to convert HDMI to Audio Video has a toggleable switch that can be changed to NTSC or PAL. I dont know what that is, both works but setting to PAL seems to be slightly clearer.

I am asking here in hopes someone else has done it and how they made it barable.

[Also I am sorry I do not understand the language that is mostly used here. This community seems to be the most active one so I decided to ask for help here]

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[–] [email protected] 1 points 1 year ago (1 children)

First off, CRT TVs have historically been interlaced rather than progressive scan, so the picture will not look as good as it would on an actual monitor.

Also if your HDMI converter is cheap, it may do a poor job of coverting the signal and give you poor image quality.

NTSC and PAL are signal standards for TV. NTSC is used in NA, Japan, and parts of South America, while PAL is used in Europe and Africa.

[–] [email protected] 2 points 1 year ago* (last edited 1 year ago)

So you mean I should enable interlaced flag to 1 in hdmi_ctv

Actually, I learned that Raspberry pi 4B supports TV AV output through its headphone jack (I feel dumb for not reading the docs previously) and so I ordered a TRRS cable. I looked at the documentation and it says that pin needs to have 4 sections on the headphone connector. I looked around and found one that broadly fits the description.

Unfortunately, Amazon or Ebay is not available in our country(Nepal) and that means I just have to do my own guess work with chineese products that has little to no documentation. The seller doesnt know what a raspberry pi is but he showed me it works in a TV box connected to the CRT and it has 4 sections on the 3.5mm pin. So I ordered it. Hopefully it works.