RgbTohdmi

Van Pencioner

Scribe (1460)

afbeelding van Pencioner

29-04-2021, 23:07

Unfortunately it seems that this can't be used with MSX because it is for TTL RGB not analog RGB...

Van PingPong

Prophet (3759)

afbeelding van PingPong

29-04-2021, 23:17

i've read that there is a small addon for analog input on github or i'm wrong?

Van Pencioner

Scribe (1460)

afbeelding van Pencioner

30-04-2021, 01:27

Yes, i missed that

Van gdx

Enlighted (4694)

afbeelding van gdx

30-04-2021, 13:26

It seems not able to support many colors (4096 with a modification). So it is not appropriate for MSX2+ and Turbo R.

Van rjp

Master (193)

afbeelding van rjp

03-09-2021, 22:25

Well, I'm trying RGB2HDMI with my MSX 2. My Sanyo Wavy 23 (MSX 2) is the testbed.

Let me see...

  1. The picture is really sharp and clear, even with big resolutions as 1920x1440. My TV is pretty lame (Lenoxx), but the images are amazing.
  2. My problem is in the colors scheme. I've been trying first with a MSX 1 palette, and as you can see in the image below, some colors can't be distinguished.
    MSX 1 pallete.

    Colors 2 and 3 (green and light green), 4 and 5 (blue and light blue), 8 and 9 (red and light red), 14 and 15 (gray and white) are indistinguishable. I've been tuning the sampling configuration so it can be more accurate, but I don't have enough information to do these adjusts (needs a oscilloscope to find the numbers). And as you can see, color 11 (yellow) is almost the same as 14 and 15 (gray and white). he RGB2HDMI configuration doesn't have MSX palettes, so I'm using a ZX-Spectrum palette, which seems to be the one which is nearer to the MSX (as Amstrad, which has less brightness).

  3. Besides, there is a funny thing: When we change background color, RGB2HDMI spends a lot of time to adjust, almost 15 seconds!

Victor Trucco (the man behind SM-X) sold me this adapter and I went to his home last week. We spent some time fine tuning the adapter, in order to stabilize the image. We were pretty successful. But the colors are really lost. Here is the config file that we created, you can download it if you can.
And here goes a second photo. Here we have the sampling menu, where we can adjust lower and upper limits of Green and Red and Blue (which are together).

Any ideas? It would be very helpful.

Cheers,
Ricardo.

Van gdx

Enlighted (4694)

afbeelding van gdx

04-09-2021, 02:33

Try with the modification to support up to 4096 colors if it is not done yet.

Van Parn

Hero (651)

afbeelding van Parn

05-09-2021, 02:58

I may be completely misunderstanding how the hardware works, but I'd try to keep some things in mind. I hope we can get some input from the hardware wizards around here, but here are my two cents:

  • Among the supported systems, an MSX2 is closer to the TI99/4A, since the V9938 is a TMS9918 successor and has similar timings. So I'd try starting with some 256x192 pixels mode and leave any 512x212 mode for a later moment.
  • I'm also concerned by the palette selection. I may be completely mistaken, but I think what it does is try to approximate detected colors to those in the selected palette. This would work wonders if your video signal isn't completely stable but you already know which colors to expect. But in the case of the MSX2 I wonder if the most appropriate option wouldn't be a 512-color, 3-bit per RGB component palette (if it's available at all).
  • I think some calibration work could be shared among people who are trying to make RGBtoHDMI work with other video processors with similar timings and color capabilities, like the PC Engine.

Van Parn

Hero (651)

afbeelding van Parn

05-09-2021, 03:19

Some info, perhaps useful. The tutorial on creating a new profile says to use the highest resolution generated by the device, so here it is for 512x212:

  • Pixel aspect ratio: 4:7
  • Pixel clock frequency: 10,738,636 Hz
  • Clock cycles per line: 512 not including the border, 568 including the border

Van rjp

Master (193)

afbeelding van rjp

05-09-2021, 04:48

Well, let me see...

  • First, I gave up of using the Sanyo Wavy 23 (MSX 2) and started using my Sony HB-F1XV (MSX 2+). The color set became much more accurate.
  • I tried the TI-99/4A palette, but it was awful. I tried a lot of palettes, and the EGA palette was the most accurate of all palettes.
  • I configured the pixel clock frequency, exactly as Parn told.

My results are somewhat better than the previous ones. Color 2 and 3 aren't the same, as colors 10 and 11. But colors 14 and 15 (gray) and 15 (white) are roughly the same. Besides, I've got a annoying vertical sync, and I tried some settings so I could avoid it, but I wasn't successful.

It's getting better, BTW. Thanks for the help, Parn! I hope I can stabilize it so everybody who wants to connect your MSX to a LCD TV, can do it. Any ideas would be appreciated.

Van Parn

Hero (651)

afbeelding van Parn

05-09-2021, 13:54

I'm really tempted to splurging out on an RGBtoHDMI myself to try and help creating a proper MSX profile for it, but I'm a bit worried about bomb carpeting my finances. Tongue I'm still very keen on seeing the results of your tinkering. I hope more people get interested about it and start sharing some info as well.