Electronics > Projects, Designs, and Technical Stuff

RGB to Component (YPbPr / YCbCr) Video Converter

<< < (3/4) > >>

Benta:
In that case, I'd check the RGB outputs with a 'scope. I have my doubts about the DVD player.

paul_g_787:
The DVD player does indeed have RGB outputs and not just composite.

I have an old SCART lead I soldered 3 switches to so I could disconnect the R, G and B leads in turn so I could see if the colours changed. e.g. if I turn off Green and Blue I only see the red.

I did this ages ago when I was learning about SCART pinouts.

DaJMasta:
Can you put it into a computer instead?  A USB analog capture stick I've bought before comes with a SCART adapter, which connects up to the composite video input for the capture card.  I wonder if it's just using some passives in the adapter to overlay the signals on the single input line.

The USB stick I'm thinking of is an Elgato Video Capture, but they don't give a ton of detail as to what the SCART adapter does.

paul_g_787:
I am not trying to capture and record video, I am trying to display RGBs video on my new TV which only has component YPbPr / YCbCr video inputs so I can play my old games consoles.

paul_g_787:

--- Quote from: Benta on June 14, 2021, 10:11:59 pm ---Looking at the schematic in the OP again, several points stick out.

The resistances in the second chain of LM6171/72s are very low, and unnecessarily so.

The three output amps of LM6171/72 class are still needed. They have to be fast, and they also have to drive a 75-ohm load at 1 Vpp (or 150 ohms at 2 Vpp). Not many opamps can do this, and they all cost around 4 Euro.

But using LM6171/72 amps just for internal buffering is wasting money. This can be done for a few cents.
The attached schematic shows a video buffer that's pretty much standard in VCRs. It'll run up to a hundred MHz at least, and has negligible DC shift.
Replace the first three amps with this

Your input DC blocking caps will need to be larger, but that's the only ramification.

--- End quote ---

This could be a good way to cut the cost! Do you have any values for the components in the schematic?

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version