Arduino TvOut / RCA with colors

Projects General Guidance
1

Hello friends, good evening here from Brazil. Does anyone know a way to get a RCA video output with color + arduino ?

I am using the TvOut library, which works super well, but only in black and white.

Thank you very much

2

Google broken over there?

maybe...

a7

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3

Thanks for the reply, I had seen this post, but in his scheme he uses vga and I need it to be rca.

4

Sry, didn't read carefully! Saw

Yes. We can use old color TV.
And we can use LCD TV or monitor with composite input.

and assumed they had achieved that.

a7

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5

How much do you know about NTSC, before we get deeply into this? There are IC's that will do it:
https://media.digikey.com/pdf/Data%20Sheets/Rohm%20PDFs/BU1425AK.pdf

6

I don't have a deep knowledge but with a wiring diagram maybe I can realize my project, thanks for your kindness

7

There are a few standards that come under the heading RCA. This is from Wikipedia

RCA video may refer to any video standards using RCA connectors.

  • Composite video (the most common standard referred to as "RCA video"
    • S-Video, some renditions of this standard utilize 2 RCA ports (luma and chroma), of which are only "half" of composite video with provisions for less crosstalk.
    • Component video, uses three "red" (Pb), "green" (Y) and "blue" (Pr) RCA ports; of which this standard also derives from the composite video standard too.

Which one do you have on your system?

Please note NTSC is not an option on an RCA system. NTSC dubbed by us in the U.K. as Never Twice Same Colour, is a way of modulating colour difference signals onto a luma signal for RF transmission. It is nothing to do with RCA.

In the UK and a lot of the rest of the world outside the U.S. they use PAL which stands for Phase Alternative Line. It is like NTSC but as the name implies ever other line the phase of the colour burst signal is inverted. This averages out any error.

So you have to know what TV standard your TV is if you want to plug a signal into the antenna socket. The signal also has to be AM modulated onto normally channel 36, in the UK at lease.

8

Back in the day when I tried to use chips like this (not sure if it was the same chip) I was never very impressed with the results. The colours always looks washed out.

9

It's a hobby project. In any case, you have no hope of achieving colour if you can't generate 3.579545 MHz exactly. How are you going to do that with a bit banged output of an MCU?

I noticed the use of "RCA" as if it were a protocol, not connector.

The IC that I have in my collection is:
https://www.smspower.org/uploads/Development/Motorola_MC1377.pdf

10

Google says that Brazil was PAL (not NTSC), and went digital many moons ago.
Do you still have a TV with analogue inputs. I don't.
I assume it's nowadays more complicated to generate PAL video than digital HDMI.
Try a board with HDMI a output, like a Rpi.
Leo..

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11

I assumed the answer is yes, it's the whole point of TvOut. Compromised PAL may be no harder than compromised NTSC. I've seen game consoles with a PAL/NTSC switch, I think it only changes the sync timing and burst frequency.

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12

Check out “avr demoscene”

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14

This entire thread left me scratching my head. NTSC is mainly based on RCA's color TV system, and is an engineering marvel given the level of analog electronics development AT THE TIME (ca. 1953).
RCA jacks, by contrast, are used for composite video, mono/stereo audio and the ALC input to Heathkit SB220 amplifiers, among myriad other uses.
I'm not sure we can help with his problem unless he better defines what he means by RCA video.

  • Wes
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15

Some call it call vacuuming, others call it Luxing or Hoovering.
Consumer-grade gear uses RCA plugs for composite video, OP seems to call it RCA-video.

NTSC is seen in PAL countries as inferiour (Never The Same Colour).
It seems the US couldn't wait for the improvements (PAL), which also happened in the sixties.
Leo..

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16

And the 180˚ phase change of the burst frequency on alternate lines.

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17

Not exactly. I believe NTSC was designed for maximum compatibility with monochrome sets, PAL was not. They had to make sacrifices to do that.

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18

I don't think that was true.

What do these involve?

The TVs that used PAL were 625 lines per frame, where as the US had 512 lines. But originally the UK system was 405 lines, which never had colour capability.

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19

It is reflected in the choice of burst frequency vs. horizontal scan timing. The general idea is, the burst frequency is chosen so it "dithers" so as to make it invisible or at least less detectable on monochrome sets. It's done by making it a non-common factor with 15750 which is the horizontal frequency IIRC.

If you ever ran a cheaply generated NTSC signal into a monochrome monitor, you would have seen the horrible results when this scheme is not respected (horz derived from, or locked to burst). There were horrible stripes anywhere there was a colour signal. Those would be invisible in a true NTSC timed signal.

But the true sacrifice, was to have to support monochrome at all, since a colour only protocol is much easier to design, with much better performance. Those systems were floated at the time, but rejected in favour of a monochrome compatible system.

I admit I don't know what the other trade offs were. But it's easy to imagine what they would entail, besides the above issue.

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20

By the way, the choice of 525 lines in the continental USA and 625 in Europe, originates with the line frequencies of 60 and 50 Hz. It's to minimize wobble in the vertical signal due to AC ripple in the set power supply.

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