Film-Tech Forum ARCHIVE: Alternative content not filling screen.

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Posted by Stephen Furley (Member # 1277) on 05-03-2014, 02:42 AM:

When the digital system was first installed it did, but not since re-install.

Screen is constant width, except for Academy ratio on film where both top and side masking move.

When the digital was re-installed I put up 1.85 on 35 mm and set the side masking to match that. The engineer then set up the digital projector to the masking, and the digital cinema picture fills the full width of the screen, so the problem is not with the projector, it's capable of putting light on the screen as far as the side masking. I recently checked the 35 mm machines with a loop of PA-35 and everything's fine, nothing has changed on those machines, so the masking must be in the same position as it was before closure.

However, when using the Cine-IPM while the image reaches the masking on the right side it does not on the left, there's a gap of about 125 mm. If I adjust the size and position of the image to try to get it to fill the screen then the image is simply cropped at the left side, as if there was a sort of under-cut electronic aperture plate; if the picture is moved beyond that point then that part of it is not seen, though the projector can fill the full width of the screen.

I thought there might be something wrong with the settings for the Channel in use, so I tried switching to input 4, the S-video one which is never used so there is no input signal, and the blue screen with the Christie logo in the corner has the same problem, so it's not just the way that I've set up the particular channel, but a general problem with anything coming out of the Cine-IPM.

On Thursday we have two screenings of a film for which the distributor has kept putting back the delivery date. By yesterday afternoon it had reached ' by noon on Wednesday' and they offered me a Blu-Ray if I didn't think we could ingest it in time. I thought we would be ok if I could take half an hour off work to go in to the cinema to start the ingest, but decided to accept the offer of the Blu-Ray as a backup, just in case. Within about an hour the delivery date had slipped by another day, to Thursday, and it is unlikely that we will be able to ingest it before the first show. Hopefully we will be able to ingest it during that show, and can use it for the evening one, but it looks like the afternoon show will have to use the Blu-Ray, so I'd like to fix this before then.

We've run other shows via the IPM in the past few weeks and each time I had to reduce the image size, centre it on the screen so it had the same size gap on each side, and then bring the masking in a bit. I don't really want to do this again, partly because the top masking then doesn't come down quite far enough to reach the smaller picture, and partly because at the moment the only way to move the side masking is to go under the screen and turn the motor shaft by hand. There's very little space between the motor and the wall, and it's difficult to get a hand in there to do it. We don't own the cinema, so repairs take time to organise; hopefully, it will be fixed soon, but since the screen is normally constant width it has not been a high priority.

I'm hoping that it's just a setting somewhere on the IPM which I haven't found yet; there are so many of them. Any ideas?

Posted by Marcel Birgelen (Member # 6801) on 05-03-2014, 03:25 AM:

Did you check the "Advanced Size and Position" in the "CUSTOM" options for your source? Check the blanking options and see if there is something configured for the "Right Blank" option?

Also, did you try to hook up something directly to your projector on the same input source to check if it isn't the projector configuration for that input?

Posted by Stephen Furley (Member # 1277) on 05-03-2014, 04:08 AM:

Marcel,

Isn't the blanking under the advanced options for blanking parts of the input signal, rather than areas of the screen, or have I mis-understood it? It's the left, not the right, which has the problem. There are just a few pixels blanked on the left; if I don't do that then the picture does't lock properly vertically, like film about one and a half perfs out of rack would look.

Good point about the same input on the projector but not going through the IPM; I'll try it on Tuesday, Monday is a bank holiday.

Posted by Carsten Kurz (Member # 5396) on 05-03-2014, 04:44 AM:

This blanking can take place in the scaler and/or the projector, as a channel specific setting. Begin with the scaler, then check the projector. You could try to connect a Bluray player or notebook directly to the projector with a 1080p signal for a quick check. If the masking/blank is still there, it's the projector/channel.

- Carsten

Posted by Justin Hamaker (Member # 2165) on 05-03-2014, 04:54 AM:

This sounds like you might just need to redo the screen files from scratch. Start with the shift/zoom/focus, then the crop files (electronic aperture plate).

Posted by Marcel Birgelen (Member # 6801) on 05-03-2014, 05:45 AM:

quote: Stephen Furley
Isn't the blanking under the advanced options for blanking parts of the input signal, rather than areas of the screen, or have I mis-understood it? It's the left, not the right, which has the problem. There are just a few pixels blanked on the left; if I don't do that then the picture does't lock properly vertically, like film about one and a half perfs out of rack would look.

Blanking/cropping is configured on the Input channels on the CineIPM. The Size and Position menu can be openend via Menu+1 if I remember correctly. The last option in the menu is something called "Advanced Size and Position". If you choose that one, it will also show the active input window size in pixels. If that doesn't exactly match your input resolution (e.g. 1920x1080 for 1080p), then there is some input blanking/cropping happening, which can be configured in this same menu.

There are three potential sources for this blanking to happen:
- Your original source
- Your scaler (CineIPM)
- Your projector

Personally, if you're already tried the obvious settings on your scaler, I would first try to isolate the device that's causing the troubles before you start randomly fiddling around on all kinds of settings on three different devices [Wink]

Posted by Marco Giustini (Member # 4544) on 05-03-2014, 06:03 AM:

Hello Stephen,

You should run a "framing chart", that will tell you if your picture is centered and/or cropped and why your picture is shifted. The projector should have some on it but you can also run a DCP. If the framing chart is fine, then your source is the problem.
HD is slightly narrower than 2K. 1920 vs 1998. Hence unless you have a dedicated setting on your projector for HD which zooms your picture out, you will have black side bars.
You could also try and find a framing chart on a DVD or BD. Search AVS-HD, it's a free test disk which runs on most players. It does not have a great selection of charts, but you should be able to find something that help.

Posted by Steve Guttag (Member # 268) on 05-03-2014, 06:40 AM:

A couple of things...are you working with a series 1 or a series 2 projector? How you go about getting the image to fill on them are different as the series 1 projectors do not have the bandwidth to scale high frame rate full frame pictures. To disable the scaler in a series 1, there is typically a "Cinema Processing" option that has to be disabled for anything but Scope images (1920x804) or you will get a cropped image as you run into the bandwidth limitations.

With series 2, there is plenty of bandwidth to scale most everything in the projector so that 1.85 or 2.39 can remain at those ratios and match the DCinema screen files.

As others have pointed out...you can lose your image in the scaler (CineIPM) or in the projector (Screen file). I suppose you could lose it physically by having the image hit an obstruction like the edge of a port too.

I'm least familiar with the CineIPM since it is not HDCP compliant, we never used it. However, if it has a test generator...I would start with that...have it put out a full raster of say white and see if that fills the screen. If so, then your issue lies in how the CineIPM was configured or possibly the source. If it does not fill the screen, then the projector's screen (and possibly PCF) file is where I would start.

And remember, HDTV stuff is based on 1920x1080, NOT 2K (2048x1080)...thus if you have a full screen 16x9 HDTV (e.g. BluRay) source, it will NOT fill the 1998 "Flat" width. If you have a 1.85 BluRay...it will not fill either height or width...more so for 2.35/2.39 scope.

The capabilities of the scaler and/or projector is how one can get the ratios to match. Since you have a scaler in the system, that is where the image SHOULD be scaled. You already are paying for the "hit" to the image for being scaled; you are better off not having it scale and then scale again. Again, I do not know all of the capabilities (or lack thereof) of the CineIPM to know if it can take a 1.85 video and enlarge it to a 1998x1080 to eliminate black bars at the top and fill the Flat image in the projector. For sure, a Barco ACS2048 can.

Posted by Stephen Furley (Member # 1277) on 05-03-2014, 06:58 AM:

Thanks for the suggestions; gives me a few things to think about. Just a thought, I'm on a bus stuck in traffic at the moment and looking at a scan of a bad photocopy of the IPM manual on my iPad. I've just seen that the output of the IPM can be set to other resolutions than 1080 x 2048. If the output had been set to 1080 x1920 could that cause this problem?

Posted by Steve Guttag (Member # 268) on 05-03-2014, 10:20 AM:

If it is set to 1920x1080, it will, for sure, not fill either a 1998 nor a 2048 width. Think about it.

Posted by Marco Giustini (Member # 4544) on 05-03-2014, 03:14 PM:

But even if you set it to 2048x1080, Full HD is 1.78:1 and a Flat movie will leave side bars anyway. Scope will not, if you set the source file correctly as Steve points out.

I would follow Steve's suggestion, find a test pattern from the IPM, but if I may suggest, use a grid, it would be easier to assess whether the side is cropped.

Posted by Stephen Furley (Member # 1277) on 05-07-2014, 06:20 PM:

It did turn out that somebody had set the output to 1080 x 1920. Reset it to 2k and it's fine now .

Thanks for the advice.