Unstable Video on Projectors

[Vitaliy]

Hi, first time on this forum, hoping to find some advice on how to solve a problem that we're having at our church.

This past summer we began to upgrade our video system. Originally, we were going all analog - 3 Sony EVI-D70's, a Roland V-8 video mixer, a Kramer VP-727 scaler/switcher, 3 Sanyo PLC-XU48 projectors, and a PC for lyrics/scriptures. The system wasn't all that great in quality -- but it worked.

However, two of the Sanyo's (the FOH ones) went out at roughly the same times. Probably due to the fact that the previous technicians bought lamps that were 1/4 of the price of the normal lamps. Also, our Roland V-8 could not last through any service, as the output would begin to flicker crazily.

Being on a very tight budget, our church gave us $2000 for new projectors. Although it's an extremely small amount for 2 projectors, our church's 20th anniversary is coming up and they wanted to have everything working.

After sifting through all of the options, we settled for the Dell 4320. It seemed to be the best choice for our budget and our church. We then bought a Panasonic AG-HMX100 to replace our Roland. This is when we started to run into problems.

The problems were first noticed when the projectors would always re-adjust whenever the video input was switched on the mixer. For example, from Camera 1 to PC. What happens is that the image shifts (or flickers crazily) to the left and the projector shows "please wait" and the image comes back, with the projector displaying resolution info at the bottom. Sometimes the projector would re-size itself for no apparent reason. Eventually I figured out that if we display an image on the PC, output it to the projectors through the system, and THEN turn on the projectors, the projectors would only re-adjust on the first switch and be more or less stable for the rest of the service.

What I can't understand is why it's re-adjusting mostly during when we switch from cameras to PC (or vice-versa). After all, the mixer is set to output 1280x720, so the resolution technically isn't changing. We have the video mixer output going to the Kramer, which goes out straight to the projectors. The Kramer is set to display at 1280x720 as well. We're also using it to stretch the 16:9 input to 4:3 proportions, because our current cameras are not widescreen compatible (we plan on buying new cameras).

If somebody can provide me tips on how to fix this problem, that would be amazing. I've spent much longer than I wanted on this upgrade (mostly because of bad planning on my side and budget constraints). I know that detailing out how our system works would help you guys help me locate the problem, but that would result in a very long post. If anyone needs anymore information, I'm more than happy to share.

Thanks in advance!

 

[techieman33]

Have you tried turning the auto adjust off?

 

[Vitaliy]

Have you tried turning the auto adjust off?

Actually, there isn't an option for that. But I'm guessing that this isn't the issue, because the image tends to jump off to the side, and THEN the auto adjust kicks in. There are times when the projectors turn on and one of them are either cropped on one side, or out of the 1280x720 resolution "frame" (they're 1280x800 native, so the image displays out of the screen frame).

I've noticed that something happens with the signal (it flickers, or the image is partially off-screen or not properly centered) and then the auto-adjust kicks in and fixes it. It's something in the signal that isn't stable, but I can't figure out what it could be.

 

[museav]

What you describe sounds like something having to resync, but I think that detailing the system is critical here as I am not clear how you are getting any image at all.

You apparently have three EVI-D70 cameras going to a AG-HMX100. You also have computer and it sounds like you also have the PC run into the AG-HMX100. Then the output of the AG-HMX100 goes into a Kramer VP-727 that feeds two new Dell and a Sanyo projector. If that is correct then it leads to a number of questions.

The EVI-D70 have NTSC composite video and Y/C outputs. The AG-HMX inputs are two composite video, four SD/HD-SDI, two HDMI and one DVI-I. So the first question is how you are getting three composite or Y/C video cameras into a switcher that appears to have only two composite video inputs and no Y/C inputs?

The AG-HMX100 Program output is SDI and DVI-D and the Aux output is SDI only while the inputs to the Kramer VP-727 are 'universal' analog inputs (composite, Y/C, component, RGB/YUV, RGBS or RGBHV). So how are you getting the outputs of a switcher that has only digital video oututs into a seamless switcher with only analog inputs? This also seems to bring up why a seamless switcher if you are only using one input? The latter may be part of the issue as you are apparently switching before a single live input to the seamless switcher rather than using the seamless switcher to switch, thus you are swicthing the input to a scaler rather than the outputs of two scalers and its internal scaler may have to resync when that happens.

The VP-727 has one Program and one Preview out, both available as component/RGBHV, VGA and DVI-D. The Sanyo PLC-XU48 has a composite video input as well as a VGA/RGBHV/component video input. The Dell 4320s have one composite video, one Y/C, two VGA/RGBHV/component and one HDMI inputs. So how do you get the Program out of the VP-727 to the three projectors?

The Sanyo PLC-XU48 is 1024x768 (4:3) native resolution while the Dell 4320s are 1280x800 (16:10) native. So why do you apparently have the Kramer set to output 1280x720 (16:9 format)? And that is just touching on all the potential resolution factors involved regarding the supported resolutions and formats and the mixed analog and digital signals involved.


All that aside, since you apparently are somehow getting an image to all three projectors, have you backtracked through the system to try to find where the problem originates? For example, have you connected a monitor direct to the Kramer VP-727 output to see if the problem exists there? Or to the AG-HMX100 output to see if is present in its output?

Have you tried using the Kramer to switch between the computer and cameras? I know this loses the production capability of the production switcher and it may not be a permanent solution but it may help identify what is causing your problem.

One possible issue is that the AG-HMX100 does not support 1280x720 resolution on the DVI-I input, only 1024x768@60Hz, 1280x768@60Hz, 1280x1024@60Hz, 1920x1080@50Hz and 1920x1080@60Hz. Have you verified that the computer is outputting one of those compatible resolution and refresh rates? If the computer has an HDMI output have you tried using that and setting it for 720p (1280x720@50/59.94Hz) to match the output?

 

[Vitaliy]

What you describe sounds like something having to resync, but I think that detailing the system is critical here as I am not clear how you are getting any image at all.

You apparently have three EVI-D70 cameras going to a AG-HMX100. You also have computer and it sounds like you also have the PC run into the AG-HMX100. Then the output of the AG-HMX100 goes into a Kramer VP-727 that feeds two new Dell and a Sanyo projector. If that is correct then it leads to a number of questions.

Yes, that is correct.

The EVI-D70 have NTSC composite video and Y/C outputs. The AG-HMX inputs are two composite video, four SD/HD-SDI, two HDMI and one DVI-I. So the first question is how you are getting three composite or Y/C video cameras into a switcher that appears to have only two composite video inputs and no Y/C inputs?

Well, our cameras are being fed to the video booth through a cat5 cable with adapters on either end that provide the power, control signals, and video signal to and from each of the cameras. However, these adapters only carry S-Video, not composite like needed to go into the AG-HMX100. I don't know analog signals that that well, so I tried buying S-Video to Composite adapters for $3 at Fry's but that only resulted in a black and white image.

What we ended up doing was to buy another component/s-video to HDMI converter for $50 and a friend of mine brought in one that he had and wasn't using. So then two of the cameras were upscaled (and stretched, because they don't support 16:9) and plugged into the mixer through HDMI.

We went ahead and did it this way because we aren't keeping these cameras for very long. We plan to buy new cameras that will input through SDI and be widescreen native.

The AG-HMX100 Program output is SDI and DVI-D and the Aux output is SDI only while the inputs to the Kramer VP-727 are 'universal' analog inputs (composite, Y/C, component, RGB/YUV, RGBS or RGBHV). So how are you getting the outputs of a switcher that has only digital video oututs into a seamless switcher with only analog inputs? This also seems to bring up why a seamless switcher if you are only using one input? The latter may be part of the issue as you are apparently switching before a single live input to the seamless switcher rather than using the seamless switcher to switch, thus you are swicthing the input to a scaler rather than the outputs of two scalers and its internal scaler may have to resync when that happens.

Well, we bought a SIIG CE-H20511-S1 DVI to VGA converter (we'd need it later anyways since the signal going to the projectors is VGA). So, the DVI program out of the mixer is going to this converter which then goes out as VGA to the Kramer.

Why we're using the Kramer is due to the fact that the cameras are being stretched, since they are 4:3 native but are being converted to HDMI. What we're doing is taking the output from the mixer, and stretching the image vertically to make the image on the projectors be 4:3 proportions. I know that it degrades quality and cuts off a chunk of the top, but we did that in order to have a 4:3 image on a 16:9 screen. As with the PC input, although it is stretched, lyrics and text look fine, although we did have to change some margins in order to have the lyrics be centered onscreen.

The VP-727 has one Program and one Preview out, both available as component/RGBHV, VGA and DVI-D. The Sanyo PLC-XU48 has a composite video input as well as a VGA/RGBHV/component video input. The Dell 4320s have one composite video, one Y/C, two VGA/RGBHV/component and one HDMI inputs. So how do you get the Program out of the VP-727 to the three projectors?

We have RGBHV coming out of the Kramer which then becomes a VGA cable on the other end. It goes to a splitter, which then feeds each projector.

The Sanyo PLC-XU48 is 1024x768 (4:3) native resolution while the Dell 4320s are 1280x800 (16:10) native. So why do you apparently have the Kramer set to output 1280x720 (16:9 format)? And that is just touching on all the potential resolution factors involved regarding the supported resolutions and formats and the mixed analog and digital signals involved.

We have the Kramer set to 1280x720 because the FOH projector screens are already painted for a 16:9 image. However, either way we can't set the Kramer to a 4:3 resolution because we can't output an SD signal from the mixer through DVI (it says out of range on all monitors).

All that aside, since you apparently are somehow getting an image to all three projectors, have you backtracked through the system to try to find where the problem originates? For example, have you connected a monitor direct to the Kramer VP-727 output to see if the problem exists there? Or to the AG-HMX100 output to see if is present in its output?

Have you tried using the Kramer to switch between the computer and cameras? I know this loses the production capability of the production switcher and it may not be a permanent solution but it may help identify what is causing your problem.

I will be at church tonight in hopes to find a temporary solution for tomorrow. I will try plugging the projectors straight into the Panasonic. I'll post here if the problem still persists.

However, I can't try switching everything to the Kramer until next week, after tomorrow.

One possible issue is that the AG-HMX100 does not support 1280x720 resolution on the DVI-I input, only 1024x768@60Hz, 1280x768@60Hz, 1280x1024@60Hz, 1920x1080@50Hz and 1920x1080@60Hz. Have you verified that the computer is outputting one of those compatible resolution and refresh rates? If the computer has an HDMI output have you tried using that and setting it for 720p (1280x720@50/59.94Hz) to match the output?

Yes, we're outputting 1280x720@60Hz from the computer to the mixer through DVI. The mixer is set to WXGA on it's PC input.

Either way, would it matter if the PC input was set to a different resolution? Let's say the PC was set to 1024x768. Wouldn't the mixer just take that input and output it letterboxed, but still at 1280x720 as program output?

 

[museav]

First, all the adpaters and inexpensive converters have got to be a nightmare in terms of signal path, reliability,latency and signal quality.

Well, we bought a SIIG CE-H20511-S1 DVI to VGA converter (we'd need it later anyways since the signal going to the projectors is VGA). So, the DVI program out of the mixer is going to this converter which then goes out as VGA to the Kramer.

Why we're using the Kramer is due to the fact that the cameras are being stretched, since they are 4:3 native but are being converted to HDMI. What we're doing is taking the output from the mixer, and stretching the image vertically to make the image on the projectors be 4:3 proportions. I know that it degrades quality and cuts off a chunk of the top, but we did that in order to have a 4:3 image on a 16:9 screen. As with the PC input, although it is stretched, lyrics and text look fine, although we did have to change some margins in order to have the lyrics be centered onscreen.

I'm confused. You said that the Kramer VP-727 is set for a 1280x720 output, which is 16:9. And you also noted that you have the AG-HMX100 output set for 720p or 1280x720, also 16:9. So it's apparently 1280x720/720p out of the AG-HMX100 and 1280x720/720p out of the VP-727, which suggests that there would be no change in resolution or format through the VP-727. However, who knows what the DVI-to-VGA converter is doing.

Think about this, if the AG-HMX100 is set to always provide a 720/59.94p output signal and if the DVI-to-VGA converter is not changing the resolution or format, simply converting that DVI signal to a [email protected]/60Hz VGA output, then the VP-727 is apparently doing nothing. So it seems that either the VP-727 is redundant or the DVI-to-VGA converter is changing the resolution or format of the signal only to have you then have to scale that back to 1280x720.

Yes, we're outputting 1280x720@60Hz from the computer to the mixer through DVI. The mixer is set to WXGA on it's PC input.

According to the manual, 1280x720@60Hz is not one of the compatible resolutions for the DVI-I input on the AG-HMX100. That could cause the AG-HMX100 to have trouble syncing the computer. So try either running the PC into an HDMI input on the AG-HMX100, which does accept 720p, or setting the computer for one of the resolutions that is compatible with the AG-HMX100 DVI inputs.

 

[Vitaliy]

First, all the adpaters and inexpensive converters have got to be a nightmare in terms of signal path, reliability,latency and signal quality.

Totally agree. They are going to be gone as soon as we get new cameras.

I'm confused. You said that the Kramer VP-727 is set for a 1280x720 output, which is 16:9. And you also noted that you have the AG-HMX100 output set for 720p or 1280x720, also 16:9. So it's apparently 1280x720/720p out of the AG-HMX100 and 1280x720/720p out of the VP-727, which suggests that there would be no change in resolution or format through the VP-727. However, who knows what the DVI-to-VGA converter is doing.

Think about this, if the AG-HMX100 is set to always provide a 720/59.94p output signal and if the DVI-to-VGA converter is not changing the resolution or format, simply converting that DVI signal to a [email protected]/60Hz VGA output, then the VP-727 is apparently doing nothing. So it seems that either the VP-727 is redundant or the DVI-to-VGA converter is changing the resolution or format of the signal only to have you then have to scale that back to 1280x720.

Well actually the Kramer is still doing something. It is taking the output of the mixer and stretching it vertically to make the 4:3 cameras not look stretched on the projectors. Because the mixer is running in 720p mode, since the cameras are 4:3 native they are being stretched to 16:9. What I did as a temporary fix was to have the Kramer stretch the image vertically back to the cameras' 4:3 proportions. This could be problem here, although I can't figure out why it should be the problem. After all, the Kramer is set to output 1280x720 no matter what is the input.

So are you saying that it could be a problem with the DVI to VGA converter as well? Even though it is in the middle, between the mixer and the Kramer? If the Kramer was to maintain the 1280x720 resolution, why would the projectors still have to readjust to changes that the converter makes? There are some EDID switches on the side of the converter, but the manual isn't too clear on what they exactly do.

According to the manual, 1280x720@60Hz is not one of the compatible resolutions for the DVI-I input on the AG-HMX100. That could cause the AG-HMX100 to have trouble syncing the computer. So try either running the PC into an HDMI input on the AG-HMX100, which does accept 720p, or setting the computer for one of the resolutions that is compatible with the AG-HMX100 DVI inputs.

Hmm...on page 32 of the manual it does show that you can set it to WXGA, but it isn't listed as one of the signal formats on page 42. Strange...

But what I don't understand is why the projectors are re-adjusting themselves. If it was a problem in the mixer, wouldn't the resolution still not change? The projectors wouldn't suspect a thing, because all they care about is the resolution, right?

The thing is, both projectors do not necessarily always re-adjust at the same time. One can be fine throughout the whole service, but the other will always do it. Yesterday, the left projector kept on re-adjusting, but the right one was fine. On another day the total opposite happens. On a third day they both do it. It's really unpredictable, which is why I just can't figure out what's wrong, because I never know when it's going to adjust again or not.

 

[museav]

Hmm...on page 32 of the manual it does show that you can set it to WXGA, but it isn't listed as one of the signal formats on page 42. Strange...

Not at all strange, WXGA can be 1280x800 or 1280x768 and the latter is listed on Page 42 as a supported resolution. So the DVI inputs of the AG-HMX100 do support WXGA in the form of 1280x768@60Hz.

It's a bit of a simplification but to a great degree the AG-HMX100 supports computer resolutions on the DVI-I inputs and video resolutions on the HDMI inputs. If you run the computer as 1280x720 or 720p then it apparently might be better as an HDMI input to the switcher.

But what I don't understand is why the projectors are re-adjusting themselves. If it was a problem in the mixer, wouldn't the resolution still not change? The projectors wouldn't suspect a thing, because all they care about is the resolution, right?

The thing is, both projectors do not necessarily always re-adjust at the same time. One can be fine throughout the whole service, but the other will always do it. Yesterday, the left projector kept on re-adjusting, but the right one was fine. On another day the total opposite happens. On a third day they both do it. It's really unpredictable, which is why I just can't figure out what's wrong, because I never know when it's going to adjust again or not.

It sounds like the problem is sync. A VGA signal has Red, Green, Blue, Horizontal Sync and Vertical Sync signals. If the sync signals drop or glitch then the projector can lose sync and have to resync to what it views as a new signal. And that does not have to be a complete loss of sync, just it dropping in level or changing in waveform enough so that it is not recognized. Any differences in the outputs of the DA, the inputs to the projectors or the losses in the cables to the projectors could result in different situations or sensitivities for each projector.

A similar situation may exist for the VP-727. Since you are using just one input on the VP-727 and switching signals ahead of it then the VP-727 seems to be acting as a simple scaler and any glitch in the sync signals coming in could cause it to have to resync.

If the VGA distribution device is a splitter that does not provide appropriate makeup gain for the sync signal splits, if not some level of gain for each output, then that could be adding to the problem.


By the way, I need to thank you as I am currently specifying the AG-HMX100 for a project and this is making me double check that I am approaching that properly. I have some advantages there as all displays and projectors involved are native 1920x1080 and the cameras are 1080/30p, 1080/59.94i/60i or 720/59.94p/60p HD-SDI, thus if the computers can provide those resolutions on HDMI outputs then I can keep the entire system as either 720p, 1080i or even 1080p. And I even get to make that easy as the computers are going to go through a digital media matrix so the related EDID can be programmed to have the computers provide the desired resolution.

 

[Vitaliy]

Not at all strange, WXGA can be 1280x800 or 1280x768 and the latter is listed on Page 42 as a supported resolution. So the DVI inputs of the AG-HMX100 do support WXGA in the form of 1280x768@60Hz.

It's a bit of a simplification but to a great degree the AG-HMX100 supports computer resolutions on the DVI-I inputs and video resolutions on the HDMI inputs. If you run the computer as 1280x720 or 720p then it apparently might be better as an HDMI input to the switcher.

You're right. When you try doing 1280x720 nothing shows up on the mixer.

It sounds like the problem is sync. A VGA signal has Red, Green, Blue, Horizontal Sync and Vertical Sync signals. If the sync signals drop or glitch then the projector can lose sync and have to resync to what it views as a new signal. And that does not have to be a complete loss of sync, just it dropping in level or changing in waveform enough so that it is not recognized. Any differences in the outputs of the DA, the inputs to the projectors or the losses in the cables to the projectors could result in different situations or sensitivities for each projector.

A similar situation may exist for the VP-727. Since you are using just one input on the VP-727 and switching signals ahead of it then the VP-727 seems to be acting as a simple scaler and any glitch in the sync signals coming in could cause it to have to resync.

If the VGA distribution device is a splitter that does not provide appropriate makeup gain for the sync signal splits, if not some level of gain for each output, then that could be adding to the problem.

Well, I think I might have found the cause of the problem. When I have the mixer connected directly to the projectors, the projectors only adjust once (which I'm guessing is a normal thing) at start but have no problems afterwards. So apparently the Kramer was causing the problems?

But I noticed one thing. When I turn on the projectors with the mixer on but not displaying anything (black image), the projectors both go into a loop looking for a signal and then adjusting to it. This happens continuously until I display an image (turn on a camera or PC on the screens) and then the projectors adjust, and the system works fine. What's happening here?

By the way, I need to thank you as I am currently specifying the AG-HMX100 for a project and this is making me double check that I am approaching that properly. I have some advantages there as all displays and projectors involved are native 1920x1080 and the cameras are 1080/30p, 1080/59.94i/60i or 720/59.94p/60p HD-SDI, thus if the computers can provide those resolutions on HDMI outputs then I can keep the entire system as either 720p, 1080i or even 1080p. And I even get to make that easy as the computers are going to go through a digital media matrix so the related EDID can be programmed to have the computers provide the desired resolution.

So, do you recommend us to not use the DVI input on the mixer? I really hope that I can get the Kramer working with the system so we aren't forced to both record and display the same thing.

I was planning to use a VGA signal from the computer (because the mixer does support analog VGA in) and split it, having one signal go into the mixer and the other go into the Kramer. That way if someone has a presentation or photos to show, we can have the PC up on the screens throughout the whole presentation without having to record the same thing (who wants to stare at the same photo when watching a video of the service?).

 

[museav]

But I noticed one thing. When I turn on the projectors with the mixer on but not displaying anything (black image), the projectors both go into a loop looking for a signal and then adjusting to it. This happens continuously until I display an image (turn on a camera or PC on the screens) and then the projectors adjust, and the system works fine. What's happening here?

When the projectors have no sync signal or a bad sync signal they are looking for something to lock to, once they see a good sync signal they lock up to it.

Basically, the projector needs to know how often and when each frame of video is starting (vertical sync) and how often and when each line within that frame should be displayed (horizontal sync). If that sync information is off then it may start the frame or lines at the wrong time, which may make the image appear shifted, while if they are not present the projector does not know what to do. It's much better explained in http://www.extron.com/download/files/whitepaper/adsp_rev1_wp.pdf.

 

[Vitaliy]

When the projectors have no sync signal or a bad sync signal they are looking for something to lock to, once they see a good sync signal they lock up to it.

Basically, the projector needs to know how often and when each frame of video is starting (vertical sync) and how often and when each line within that frame should be displayed (horizontal sync). If that sync information is off then it may start the frame or lines at the wrong time, which may make the image appear shifted, while if they are not present the projector does not know what to do. It's much better explained in http://www.extron.com/download/files/whitepaper/adsp_rev1_wp.pdf.

I don't think I mentioned this before, but the issue only happens on the newer Dell projectors. On our old Sanyo stage projector, the issue never occurs.

Also, so it is the Kramer causing sync issues here? What can be done about this? I'd really love to be able to use the Kramer in the system.