HDMI switcher with glitch-free selection?

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DaveOwen

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#119073 19-May-2013 16:37

I need an HDMI switcher to select between several sources to feed a projector. The thing is that I need to use it "live" when I'm doing presentations - I'll be cutting between the sources as I go so I need it to make the cuts without visual glitches. In other words I want it to be like a professional vision switcher that cuts between cameras etc.

My sources will be two computers and a Blu-ray player. My guess is that I'll need more than a simple switcher to synch and mix these sources smoothly but I've never used an HDMI switcher so I don't know. Is this possible or even normal behaviour for HDMI switchers? Any one want to recommend a good one?

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BDFL - Memuneh
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#822012 19-May-2013 17:10

Check some of the HDMI Swither listings at Rapallo. I bought a two way one that automatically switches from a source that is turned off to the previous source, or switch on demand by pressing a button. They have other models but the idea is simple...

DaveOwen

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#822059 19-May-2013 18:25

Thanks but the question I need answering is whether these switchers can cut smoothly, without any visual glitch at all, when you select a new source. It has to be able to cut between sources often and the audience should never see any rolling, breakup or momentary loss of picture stability. It has to look just as smooth as a video cutting from one shot to the next - as if was all part of the same video. I hope that's a bit clearer.

freitasm

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#822099 19-May-2013 19:38

I don't see any problems - images just switch between sources. Obviously no effects at all.

richms

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#822119 19-May-2013 20:43

They dont do that at all, displays blank out and show the input name briefly on all the ones I have tried. 1-1.5 seconds black between sources.

Might have better luck with something with some processing between the switcher and a display that would re-clock things and hold the last image till it synced and negotiated HDCP with the new device. Has anyone tried putting a switch on the upstream side of a home theater reciever that does upscale etc?

Richard rich.ms

DaveOwen

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#822122 19-May-2013 20:48

@freitasm: If that's the case then it's good news, but with respect, it's not obvious to me that it should be so.

For example, I have an old VGA switcher. I can select between two different sources to feed one monitor. When I change the selection there is a momentary flicker in the picture. For normal use it's not an issue but if the same effect was happening every 10 seconds on a large projector screen, it would become unacceptably distracting for the audience.

It's the same thing with two video camera feeds. If you use a simple passive switch to cut between them you'll get a brief but nasty picture disturbance every time you cut. To avoid this you need an active mixing device or genlock to keep the two video feeds in sync and prevent the breakup.

I'm not familiar with HDMI switchers so I don't know if the same effect would happen with them. Given that it happens with just about every other type of video signal I've ever worked with, I kind of assumed there would probably be some sort of issue with HDMI too. If not then I'll be a happy camper.

@richms: Thanks, that's what I'm talking about.

ubergeeknz

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#822168 19-May-2013 22:44

HDMI isn't a video signal, it's a digital stream. I think you'll find that switching will give you a blank screen for a second or so, that's it. Not a flicker, flash, resync, like you might see with analog video signal switching.

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#822185 20-May-2013 02:40

The rapollo guys may be able to help you. I have found then very helpful in the past. Maybe flick them an email with your requirements.

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Dunnersfella

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#822258 20-May-2013 10:01

The HDCP handshake will cause a delay / blank screen / some sort of lack of fluidity in your presentation.
I'm yet to see a product that doesn't do it...

Can you not fill your presentation, edit it up and present it as one full length video?

DaveOwen

6 posts

Wannabe Geek

#822546 20-May-2013 17:09

Thanks for the replies, that's exactly the kind of info I was looking for. At this stage I'm going to buy a cheap switcher from Dick Smith just to do a proof of concept, then if all goes well it looks like I'll need to spring for something like this:
http://www.rolandsystemsgroup.com/products/100118

Just in case anyone else is googling the same thing, another option is www.vidblaster.com. It's a nice software-based solution that I've been using for a few years but for various reasons I want to move on from it. Worth a look if you're in a similar situation though.

Can you not fill your presentation, edit it up and present it as one full length video?

No, I use a combination of pre-recorded and live sources. My presentations also need to adapt on the fly in response to the audience - I usually don't know in advance their ages, level of knowledge on the topic, etc. If they're getting bored I speed things up; if they're very engaged I give them bonus extra material. I need to be super flexible.

Dunnersfella

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#822873 21-May-2013 11:39

Hmmmm - just watching an HD Nation episode, and they mention switches with 'Instaport' will switch in a second, or less. It sounds like the tech. you're looking for!

kiwiharry

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#822931 21-May-2013 13:17

Unsure if something like this is suitable for your job.

http://www.extron.co.nz/product/product.aspx?id=swhdmi&subtype=547&s=4

Blurb says "They feature EDID Minder®, which maintains continuous EDID communication with connected devices and ensures that the HDMI sources power up properly and maintain correct video output."

Unsure if that means vision is always present. Maybe worthwile dropping them a question.

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Dunnersfella

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#822940 21-May-2013 13:23

Thumbnails of the HDMI connections could also be handy I'd guess... you know, to double check what the current status of that input is.

kiwiharry

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#833154 9-Jun-2013 18:15

How did you get on with this Dave? Did you find a suitable solution?

If you can't laugh at yourself then you probably shouldn't laugh at others.

DaveOwen

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#835675 12-Jun-2013 12:04

Thanks for the Extron link. It took me a while to find someone who could actually sell me one but in the end I got a quote for a true instant-switching device for about $3000. I didn't buy it because I also found a fully-featured vision switcher for around the same price, which is what I went for. It's a Blackmagic Design ATEM Production Studio 4K:
http://www.blackmagicdesign.com/nz/products/atemproductionstudio4k/

Unfortunately it's not going as well as advertised. Theoretically it can take HDMI from any graphics card that supports a broadcast resolution (I'm using 59.94i). In practice it doesn't. I've used an HDMI>SDI converter to make one of my PCs compatible but I'm still having trouble with a couple of others. It looks like I might to have to get a scan converter to fix the problem. I contacted Blackmagic Design to express my displeasure and they have kind of confirmed a problem - I'm still waiting to hear back from their tech before I make a final decision.

On the plus side I'm now using a "proper" vision switcher that includes mixes, wipes, keying, etc. So it's much better than a simple cut-switcher.

Thanks again for all the helpful replies in this thread. Much appreciated.

profrink

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#835693 12-Jun-2013 12:31

DaveOwen: Thanks for the Extron link. It took me a while to find someone who could actually sell me one but in the end I got a quote for a true instant-switching device for about $3000. I didn't buy it because I also found a fully-featured vision switcher for around the same price, which is what I went for. It's a Blackmagic Design ATEM Production Studio 4K:
http://www.blackmagicdesign.com/nz/products/atemproductionstudio4k/

Unfortunately it's not going as well as advertised. Theoretically it can take HDMI from any graphics card that supports a broadcast resolution (I'm using 59.94i). In practice it doesn't. I've used an HDMI>SDI converter to make one of my PCs compatible but I'm still having trouble with a couple of others. It looks like I might to have to get a scan converter to fix the problem. I contacted Blackmagic Design to express my displeasure and they have kind of confirmed a problem - I'm still waiting to hear back from their tech before I make a final decision.

On the plus side I'm now using a "proper" vision switcher that includes mixes, wipes, keying, etc. So it's much better than a simple cut-switcher.

Thanks again for all the helpful replies in this thread. Much appreciated.

Should have gone with the BM ATEM TV Studio and saved a lot of money.

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