WHY to simulate wrong convergence of LOW QUALITY tv set screens?

By flyguille

Prophet (3031)

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29-08-2017, 01:06

I discovered this youtube channels, which compare the official games across all platforms, staring with the ARCADE version.

But when MSX or MSX2 comes in scene this guy is emulating a defective TRC, like RGB beans not impacting at the same triad.

One thing is emulating the raster line, I understand that, other is emulating the GLOW the pixels has, I understand that., other thing is emulation NTSC or PAL color encoding (so color clash), if you want to emulating it in a old TV SET, but.... he is emulating, wrong convergence problems.

Now, how the hell there is a programmer which coded that dissaster of picture?.

And which emulator does that?.


just see those text chars, in black background and white character there is not any distortion in TV sets about colour, because there is not color information at all, so if that is trying to emulate color clash, the approach is wrong, so, why to emulate defective TV sets?.

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By Manuel

Ascended (19678)

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29-08-2017, 23:52

Ask him?

By the way, I don't see the effect you are speaking of. I do see some post-processing: a stretch with interpolated colors.

By Louthrax

Prophet (2496)

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30-08-2017, 00:27

Errmm, are we sure that this is emulated? I can see the problem you mention on the MSX part of the video, I have some old CRTs here that are exhibiting the same thing. I doubt an acquisition card could create convergence problems? But I also doubt he shooted a real CRT with a camera??

By Grauw

Ascended (10821)

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30-08-2017, 01:12

Maybe it’s some form of CRT shadow mask / aperture grille emulation, recorded at low resolution (so it looks weird)? E.g. openMSX’s RGBTriplet scaling algorithm. Retropie and fMSX also have such options.

By flyguille

Prophet (3031)

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30-08-2017, 15:59

convergence problems is very hard to emulate, first, the CRTs if has calibration problems (which is corrected with magnets sticks on the TRC neck), well the beans has convergence problems normally in the corners, very bad quality TRC can has it in the middle-sides, but when near to the center it normally dissapear the problem.

other convergence problem can be in the RINGS on the neck, but that shifts the beans on the whole screen, and it is impossible a tv set left the factory with a calibration problem like that.

so all left in low quality is TRC without magnets calibrations, factories that don't bother to set it acurate so they can made more units per hour.

The needs of magnets normlly comes about a bad yoke winding, or a missalign in the canons, not all the assembly, but a missaling by example of the RED against the other two, so all the assembly can be aligned towards the screen, but the red has problems to reach certain areas.

so they insert magnets in the neck under the yoke to calibrate it.and according the orientation of magnetic fields, it can cut only the bean of a certain canon, and not the others, because a canon's beam can be closer than others, so each beam is being impacted differently, and that way correcting the problems,

By flyguille

Prophet (3031)

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30-08-2017, 16:06

but why bothering to emulate that, I don't know.

Whats coming? emulating the dirt on the TV set screen?

By Samor

Prophet (2222)

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30-08-2017, 16:29

I watched some of that channel's videos (pacman, mappy) and again the MSX parts have the weird color bleeding thing going on.

Didn't blueMSX have a "tv mode" or something? Maybe it's that. Can't properly try it as DDraw filtering hasn't been working since Vista and the emulator was never properly updated to fix that.