[pinteresque]

Hello everyone - first time poster but long time lurker here. I've indirectly gained much advice and help over recent months - thanks! However, I have a few issues that are beyond my limited understanding (I'm fairly new to video projection).

I'm video designing and operating projection for a theatre show. I've done it before but had a lot of support, this time I'm on my own! My set-up is as so:

Macbook Pro to Videotech VMX400 mixer (via VGA-composite analogue converter w/ 1280x1024 resolution) to Optoma EP781 projector (XGA) via 20m(!) s-video run. Projecting to a large cyclorama approx 3.5x4m.

The quality of the projected image is poor. Looks out of focus and fuzzy, despite the projector being set to optimum settings and focus. I know I'm not going to get complete clarity of image but I've had it better than this before. I don't know what I'm doing wrong.

My confusion lies in whether this is to do with resolution or with signal type or distance of signal.

- What resolution should I set the output display to, on my Mac settings? And with this in mind, what size video should I export from my video editing suite (Final Cut Pro).

- The only outputs from my mixer are S-Video and composite. Am I right in thinking that my best and cheapest option is to use s-video straight from mixer to projector?

- If so should I be using a s-video signal amplifier to boost the signal over my 20m run? Can anyone point me towards an appropriate product? (Something like this, for example? http://www.cyberselect.co.uk/product/1027 )



As you can see I'm a tad inexperienced and would really really appreciate any assistance whatsoever

Thanks, Billy

[Gordon @ Convergent AV]

If yaou re going via svideo to the projector then you are limited to either 576i or 480i image. You are downgrading your original image considerably by doing this.

I would have thought the bet solution would have been to try to go to the projector in its native resolution via either a digital (DVI or HDMI) or HD15 (VGA SOCKET)

Also if the image is very large (As it appears it is) then its pretty likely it'll look ropey and dull unless the viewers are a consdirable distance away and it's a very very bright projector.

[pinteresque]

Thanks for your reply.

Originally Posted by Gordon @ Convergent AV

If yaou re going via svideo to the projector then you are limited to either 576i or 480i image. You are downgrading your original image considerably by doing this.

I would have thought the bet solution would have been to try to go to the projector in its native resolution via either a digital (DVI or HDMI) or HD15 (VGA SOCKET)

So would it be better to go from composite output to one of these inputs? What would I need in order to convert back to digital signal (given that I have already spent most of my budget!)?

Also if the image is very large (As it appears it is) then its pretty likely it'll look ropey and dull unless the viewers are a consdirable distance away and it's a very very bright projector.

Yes there is a certain element as there's only about 9m between the image and the first row of audience, but my instinct and short experience tells me the current ropeyness is excessive. My projector is 4500lumens with 3000:1 contrast ratio.

[bxd]

Hi,

I've been writing this as you posted:

I agree with Gordons comments but I'm not sure why you need the Videotech unit. Do you need to 'mix' regular video into what you're projecting? If you don't need to do that, you could simply send vga from your mac to the projector. You'll need a dvi to vga adapter _ I assume that your mac can output a vga signal.

You can use something like this:

Extron RGB 202xi Universal Dual Input Interface on eBay (end time 31-Aug-09 09:45:31 BST)

to give the signal a bit of a boost (it might not need it). I'm not suggesting that you use this particular unit but Extron have plenty computer / display interfaces that would do the job for you. You'd have to run rgbhv cable to the projector_ if you use a vga-vga cable make sure you use a decent one.

Brian

[pinteresque]

Originally Posted by bxd

Hi,

I've been writing this as you posted:

I agree with Gordons comments but I'm not sure why you need the Videotech unit. Do you need to 'mix' regular video into what you're projecting?
Brian

Sorry, I should've said, I need the Videotech mixer because at times I need to mix other feeds with my Mac feed (DVD and live camera). Unfortunately it is a bit of an old consumer mixer (but a good, reliable one), that I am stuck with.

Would it be worth converting the signal from the mixer to something else (DVI/VGA perhaps?), or should I stick with a driven S-Video run?

[bxd]

Hi,

As Gordon suggested earlier, you're limited to video resolutions particularly with the mixer in use. If anything, you could use a video scaler (and you're in the right forum for that) to 'de-interlace' and 'scale' the output from the mixer to a resolution similar to that of your mac. With the right upscaler you could simply switch between the upscaled signal and the mac.

Something like an old Lumagen VisionPro with rgbhv inputs could do that quite nicely. They come up on the classifieds forum at reasonable prices. There have been a couple of other basic scalers on there recently. However, you should have a read around about the subject (deinterlacing and upscaling) before you commit to doing this.

To help explain (at a simpler level), you could use something like this to convert video to vga:

Video to VGA Converter | VGA/TV Converters | Sharing, Converting, Extending | LINDY UK

The act of deinterlacing your video signal would probably improve your situation and you could use a computer monitor switcher (again look at extron on ebay and the one on the Lindy site) to switch between mac and video inputs.

However, doing things this way wouldn't allow you to do any 'mixing' between your signals - as this is all done after your mixer. It'll all depend on how important that aspect is to you.

Where are you located? _ someone might have an older processor around that you could try.

Brian

[pinteresque]

Thanks for your suggestions.

Unfortunately i cannot do without the mixer. I need to be able to mix and fade signals in time with action on stage.

Therefore I assume that the best option would be to place a video-VGA converter like the Lindy one you linked to, between the mixer and projector? This would be better than just running s-video or composite to it? How about a video-HDMI or DVI converter (vs VGA)? Like this one: http://************/l9k63o ?

Again thanks for your advice

I am based in East and South-East London. Show's in New Cross.

[Gordon @ Convergent AV]

Putting an upconvertor like the Lindy thing inline is just altering where the conversion to a higher res is done. The projetor has a device in it to do the same thing and it is unlikely the Lindy will be any better.

Do not use composite...it is the lowest video quality available.

Try calling Joe Fernand at The Media Factory and ask for his help

Media Factory - Install, Connect and Control your Home Theatre equipment!

He has probably done this sort of stuff alot of times before and may have sage advice

[bxd]

Originally Posted by Gordon @ Convergent AV

Putting an upconvertor like the Lindy thing inline is just altering where the conversion to a higher res is done. The projetor has a device in it to do the same thing and it is unlikely the Lindy will be any better.

Do not use composite...it is the lowest video quality available.

Hi,

I wasn't really suggesting the use of the Lindy unit _ I was just using it as an example to explain what something like a basic Lumagen would do. I wondered if upscaling the video without having to downscale the output from the mac might be a bit more sensible. However, if pinteresque has to 'mix' the mac output with other sources then that's not going to be an option.

I also wondered if a rgbhv signal might be a bit more robust than a composite or s-video signal over 20m (particularly if you boosted it a bit with a 2nd hand Extron unit).

As Gordon suggests the use of s-video would be an improvement on composite but I guess that all depends on having sources that have s-video outputs. If all you have is composite video then you may have to stick with it.

Check and see if the picture is better (from one of your sources) if you use a shorter cable length? _ if it is, it might be the 20m cable that's the problem.

Try the source through the mixer with the short cable to see what difference the mixer makes?

You could also try setting the output resolution from your mac to ~800x600 (s-vga. That's close to the standard def tv resolution of your other sources so it might be less trouble for the vga to video converter to handle.

Brian

[pinteresque]

Thanks for all the advice so far. I am going to try swapping the cable for a better quality one, and inserting a line driver/amp after the mixer.

I am still really confused about resolutions, though. One thing I always struggle to get my head around! Could somebody confirm for me what I should be outputting from a) Final Cut Pro and b) my Mac? Sorry as you can see I am winging this whole process a bit

[choddo2006]

No point amplifying the signal, 20m isn't far for s-video. A better quality cable may help but not by much. The big problem is you are taking a HD signal from the Mac and converting it to a dodgy SD signal then sending that over s-video which needs to then be scaled back up by the PJ.

Can you not use software mixing on the Mac and then just native digital through to the projector?

You want to outut from the Mac whatever the res of the projector is, ideally (although with the matrix in the loop it's irrelevant, it's going to trash whatever it gets sent anyway)

Final Cut Pro - as high as it will let you as long as the Mac can render it without dropping frames.

[pinteresque]

Thanks for all the advice. The problem was to do with resolution. I changed my output resolution on my Mac to standard definition (well, 800x600) and the image became much sharper. A better quality cable and an amplifier helped as well.

Now I am having a different problem, with my live feed.

The live feed is coming from an old compact hi-8 camcorder to my operating position via S-Video cable (again, best of a bad bunch of options).

The image is decent, but it is vibrating from side-to-side (is this the same as 'jitter'?) for no apparent reason. It is constant and is not to do with the operator's hand shake. Obviously when the image is being projected onto a cyc, it is huge and so it looks awful.

I think it is a signal issue and is easily resolved but nothing I've tried so far has worked. Any ideas? Could it be interference from other sources (it is travelling a long way)?

Thanks for any suggestions!

[pinteresque]

RE: Vibrating image problem - I fixed it. It was the camera's anti-shaking function misbehaving. Turned it off now.