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I wan to build a video switcher with 2 channels, something that has 2 video input (left/right channels) and 1 video output. And control it with Arduino.

The input channels will be 2 dvd player and the output will be a videoprojector.

I don't use normal mechanical relays because of I am afraid of some glitch when I switch the channel, this is the most important thing: the switch must be fluid, no light interruption, no glitch, no flickering.

I've seen in the internet those 2 possibility: NJM2244 and DG542DJ-E3. But I don't know which fits more my needs.

Do they requires some extra regulation? Are the right IC I need?

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  • \$\begingroup\$ What kind of video? The term covers anything from RS-170 analog monochrome to high-definition digital color over DVI or HDMI. \$\endgroup\$
    – Dave Tweed
    Commented Sep 7, 2013 at 0:06
  • \$\begingroup\$ 1024x768 colored video. I got the file in h264 mov, recoredered with DV camera, and have to burn dvd with it \$\endgroup\$
    – nkint
    Commented Sep 7, 2013 at 0:14
  • \$\begingroup\$ Standard Composite video I'm assuming, considering it's a dvd player and a car video system. \$\endgroup\$
    – Passerby
    Commented Sep 7, 2013 at 1:58
  • \$\begingroup\$ car video system? \$\endgroup\$
    – nkint
    Commented Sep 7, 2013 at 8:36
  • \$\begingroup\$ @nkint isn't that what you meant by beamer? A BMW? \$\endgroup\$
    – Passerby
    Commented Sep 7, 2013 at 22:59

2 Answers 2

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In general, to get completely seamless switching among live video sources, you need to make sure the sources are frame-synchronized. In a studio, this is accomplished by having all sources (cameras, playback machines) synchronized to a common master clock. If your sources are synchronized and you're dealing with analog video signals, then the analog switches you've suggested might work.

In other situations, when the sources can't be synchronized, a frame buffer can be used to time-align one source with another. But this is not the sort of thing you're going to find in a single chip.

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  • \$\begingroup\$ So I cannot easily synchronize 2 dvd player \$\endgroup\$
    – nkint
    Commented Sep 7, 2013 at 8:37
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The method used in one low-end "dumb" domestic use video switching system I have seen, consists of shutting down the video signal very briefly to a blanking signal, then switching on the second source. This brief blank period of a few frames allows the receiving device to resync to the new source, without the frame glitches mentioned.

No, something like this is not typically a single-IC solution. It takes a bit more than that.

For more sophisticated systems, as mentioned in other answers and in comments, the switching device needs to have a frame buffer and mix in the two source signals. This also allows the cross-fade transition between sources (and, optionally the picture-in-picture features) that some AV modular receivers offer.

Note though that for a simple frame-buffer based transition or switching system, the two DVD sources must have the exact same resolution and output format: Just having identical DVD players is insufficient, the source DVDs being played must be of the same audio and video specifications.

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