Projector composite input problems

[Robinba]

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| id="td_post_19048710" | Hi!

Im writing inthe hopes there is a projector guru trailing these forums...

Im interested in learning why it seams more expensive projectors like epson EBG5100 or g5200w tend to be more accepting to an unstable analog signal than a cheaper projector . Why is it that these projectors can keep showing a garbled up composite signal with no problem, and the cheaper ones just cut out. Show a blue screen or start scanning inputs.

I work with unstable analog signals as an effect and im interested in finding out whats in the expensive projectors so that i can maybe buy some unit that i can put between my garbled signals and whatever projector i come across.

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[ruinexplorer]

I'm not entirely sure what you are looking to achieve with the unstable signal. Are you looking to create a grainy image? Can you instead send a good signal of an altered image that looks to be imperfect?

 

[museav]

Sometime you get what you pay for and more expensive projectors will often use better components and especially better internal processing, thus being more forgiving regarding the signals they can accept and properly display. There's nothing you can put before the projector to change that, all you could probably do is to make the signal quality that so poor that even the best projector can't accept it.

 

[Robinba]

I'm not entirely sure what you are looking to achieve with the unstable signal. Are you looking to create a grainy image? Can you instead send a good signal of an altered image that looks to be imperfect?

Look at this link Awesome Dubstep-captain credible - YouTube - this is a more successfull attempt, the projector is a epson g5200w but you can see it drops out 2 times within this song. Allthough this projector is very forgiving to work with, i am unable to allways ask for this projector at venues etc.

so i am mixing composite signals together "dirty style" and the sync signals are getting muddled and glitch out the image. This i do want.

I have thiught about time base correctors, but i wonder if that would only stabalize the image and glitching, defeating the purpose?

Yesterday, 09:52 AMmuseav

Re: Projector composite input problems
Sometime you get what you pay for and more expensive projectors will often use better components and especially better internal processing, thus being more forgiving regarding the signals they can accept and properly display. There's nothing you can put before the projector to change that, all you could probably do is to make the signal quality that so poor that even the best projector can't accept it.​

I agree on cash equalls better components etc...
Not understanding your last sentence though? Make it so bad nothing works? Lol

 

[ruinexplorer]

What I would recommend trying is a sync pulse generator. Basically it will send a timing signal, allowing the projector to not drop the signal.

 

[museav]

It is the exact opposite of what is normally desired but I believe you are tryinbg to get rolling, tearing, etc. as a visual effect, see karlklomp | tools and VIDEO CIRCUITS: Dirty Video Mixer.

A 'dirty video mixer' is really a simple non-sync mixer, since the sources are not sync'ed you get rolling and tearing when two sources are mixed. Better processing on the projector input can better handle the resulting unstable sync signal without completely losing sync but less capable devices will lose sync if it deviates too much from what is expected. From what I've read, apparently some people use a 'dirty' mixer in front of a TBC or 'normal' vdeo mixer with internal TBCs on the inputs to try to get the effect but with a stable sync to the projector, but I don't know how well that works.

 

[Robinba]

What I would recommend trying is a sync pulse generator. Basically it will send a timing signal, allowing the projector to not drop the signal.

Ok? How would i implement this? As from wgat i managed to google, they are just a box that sends sync signal..so id have to have it connected to my mixer and make sure it sends strong enough signal to override the mangled ones? Or is there some input on the projector this would be connected to other than the composite video input?

 

[AlecIrwin]

The projector thinks it is getting a bad video signal and is thus dropping it. I have run into this problem before with digital televisions and my analog wireless camera equipment, which is cheap, and looks "garbled" as it searches for signal. I was able to solve this by finding an old VCR/DVD player with an input in/out of its own. The VCR/DVD player (or any other intermediary video source you choose to use) will send a constant video signal to the projector, thus satisfying its need for a good signal. The VCR/DVD player (or again, whatever type of device you find) will not be picky at all.

Best of luck!!!

 

[Robinba]

The projector thinks it is getting a bad video signal and is thus dropping it. I have run into this problem before with digital televisions and my analog wireless camera equipment, which is cheap, and looks "garbled" as it searches for signal. I was able to solve this by finding an old VCR/DVD player with an input in/out of its own. The VCR/DVD player (or any other intermediary video source you choose to use) will send a constant video signal to the projector, thus satisfying its need for a good signal. The VCR/DVD player (or again, whatever type of device you find) will not be picky at all.

Best of luck!!!

Thanks for the tip! What makes\models have you had this work with?

 

[AlecIrwin]

The make and model I don't think would matter, as the concept should work for any DVD/VCR player with video inputs as well as outputs. Look around, see if you can find one, maybe a friend or a thrift shop.

To answer the question I believe it was a Toshiba DVD player and a Epson projector. Might be remembering it incorrectly.

 

[ruinexplorer]

Ok? How would i implement this? As from wgat i managed to google, they are just a box that sends sync signal..so id have to have it connected to my mixer and make sure it sends strong enough signal to override the mangled ones? Or is there some input on the projector this would be connected to other than the composite video input?

Sorry it has taken me so long to reply. Basically, you would loop through one or more signals (depending on the model you had) and it would send a constant blank signal of which your signal would be on top of. This is part of a genlock which would provide a glitch free signal for broadcast (giving a common starting point for the interlaced signal). However, with the pricepoint of a sync pulse generator, the VCR idea would be considerably cheaper if you can get that to work. My biggest concern is making sure the VCR doesn't mind the signal you are giving it and display a "no signal" message. At least VCRs are cheap these days. If you have a local thrift shop, you could probably pick up a couple for really cheap.