Horizontal lines not matching CRT scanlines

[ultraover]

Quite a bit of a task to properly explain what is going on, but it is pretty much this.

I am using pi3 with 240p settings over composite, indeed outputting progressive as I can check in 240p suite (mega drive version, using pico drive).

However, I noticed in game that something was off with the image, so I went back to the test suite and checked horizontal lines... well, this is what i am getting:

i am using custom aspect ratio with horizontal resolution of 448 (2x). I tried 480 and every other close to it to try to match the lines with crt's, but no good.

Vertical lines at 640 (2x) look okayish imo:

I am aware of this topic, but cant get the shader the author mentioned.

Hope to get some help, thanks in advance.

[sleve_mcdichael]

@ultraover you're on a CRT...and you're using a scan line shader?

[ultraover]

@sleve_mcdichael nope, I am using no shader

[sleve_mcdichael]

@ultraover oh sorry, I misunderstood.

[dankcushions]

i should be clear and say there are no physical lines on a CRT that it is matching up with. the scanlines on 240p on a consumer CRT are signal artefacts because it is only sending content on every other line. this looks like a shader is running or the output resolution is incorrect/misaligned (eg, sending/not sending overscan). a copy of your config.txt and verbose log of the test suite would be useful.

running a vertical game on a CRT at 240p doesn't really makes sense unless you physically rotate the unit.

[ultraover]

@dankcushions hello, I am aware of how the crt image is generated, I just failed the properly explain the issue. But thanks to you, I revisited the config file once more and realized it was an overscan setting that was preventing the correct size of the image being displayed. Now everything works beautifully. Thanks a bunch.