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]

  • moody@lemmings.world
    1·
    1 year ago

    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.

    • cy_narrator@discuss.tchncs.deOP
      2·
      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.

  • RxBrad@lemmings.worldEnglish
    1·
    1 year ago

    I think we’re gonna need a picture.

    Sounds like you may not be particularly familiar with CRT TVs, which had much lower fidelity than VGA monitors of the era.

    640x480 resolution is more along the lines of a target resolution you’d be aiming for. And even that is pushing the limits. You aren’t going to be seeing individual pixels unless you go down to 320x240, and even that’s with some squinting and imagination.

    What you’re describing may be completely normal for a CRT TV. Particularly one using composite cables (yellow/red/white) at any point in the chain.

      • RxBrad@lemmings.worldEnglish
        2·
        1 year ago

        Honestly, that looks about right for 800x600 content on a CRT TV.

        Try bumping it down at least to 640x480. You may even need to go all the way down to 320x240. Really.

        This was life in the 80s & 90s.

        • cy_narrator@discuss.tchncs.deOP
          1·
          1 year ago

          Sure, I think I will try 320x240 since 640x480 clearly didnt work. Should I/Could I set the frame rate to 30fps through config.txt hdmi_ctv option? Also should I set it to progressive or interlaced?

          • RxBrad@lemmings.worldEnglish
            2·
            1 year ago

            If you’re playing games, I’d actually recommend sticking to 640x480 if at all possible, and trying to increase the font size in any UIs you have running so they’re readable.

            Most game consoles ran at odd resolutions that don’t divide evenly into 320x240, so you get weird scaling issues. I’ve had best results running at 640x480; setting a custom viewport in Retroarch & manually adjusting the x & y resolutions to fit the screen for each system; and then applying the sharp-bilinear-2x-prescale shader to every system.

            If you’re in the US, I’d stick to NTSC 60fps. If you’re elsewhere like Europe, you’ll likely use PAL 50fps.

            It’s likely that your HDMI adapter is probably converting whatever signal you pump into it to 480i, so I’d just pick whatever looks best between progressive and interlaced.

            • cy_narrator@discuss.tchncs.deOP
              1·
              1 year ago

              I live in Nepal which is neither US nor Europe, this is whats confusing me more.

              Well, what I found was both NTSC and PAL works over HDMI (I purchased a Composite to HDMI converter) though NTSC is worse than PAL. So I assumed my TV is PAL.

              I dont really have any aim for this “project” I just noticed this old TV lying right across my bed doing nothing and now I wonder if it can do anything.

              I will likely use it to watch Youtube videos or something. I do have a DVD player compatible with this TV but it would be nice if I could make it more powerful than that. Afterall, I dont have any other 24 inch display for larger video.