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[mojave]

On Monday evening I was helping AVSForum member nebrunner connect his subwoofer. Like many that make dedicated home theater rooms, he has a 2.35 aspect ratio screen. Some of the newer projectors have an auto-zoom function for reducing the size of 16:9 content so its height fits into the 2.35 screen. His has an older projector and he is wondering how to handle it.

Here is what he posted today about his issue:

The htpc has all of my blurays ripped to it using makemkv. I have it zoomed out so that 2.35:1 material fills the screen and 1.78:1, 1.85:1, 4:3 material etc, all spill over the top and the bottom onto the black velvet masking.

My plan was to set the permanent resolution on the htpc to 1920x800 or 1920x817, not have it zoomed, and then I thought the scope movies would fill the whole panel and match the screen, and smaller aspect ratio movies would get shrunk down by the htpc and fit the screen. I'd lose some resolution on the smaller aspect ratio shows, but it should be good enough for now until I upgrade to a projector that does auto-zoom.

I tried setting it up that way and it worked perfectly for the 1.85:1, 1.78:1 shows, but all of the 2.35:1 were being shrunk and displayed with black bars on all sides. It was hard to figure out what was going on, there isn't a lot of info out there about this kind of thing, I guess the market is small for constant image height using an older projector and people who want to use their pc to shrink their source material. What I think is going on is that the blurays I transferred to the htpc, the black bars on the top nad bottom are actual black images that are included in the source. I'm going to try and use handbrake to re-encode the images while cropping out the black bars, then project them and hopefully the image fills the screen.

He wants the original aspect ratio to fit in his screen without any stretching. Does the "crop black bars" feature automatically zoom for each aspect ratio?

[Matt]

Does the "crop black bars" feature automatically zoom for each aspect ratio?

If I'm understanding correctly, yes. 

'Crop Black Bars' is a zoom that preserves aspect ratio (so pixels remain square).

[mojave]

I tried "crop black bars" and it is the reverse of what he wants. His regular computer image (1920x1080) spills over the top and bottom of his 2.35 screen. When he watches 2.35 movies, it fills the screen perfectly. When he watches 1.78 (16:9) or 1.85 shows or movies, then the image again spills over at the top and bottom. You can manually reduce the zoom for the image to fit, but I can't find a global setting.

[Matt]

Are you saying the projector is 1080p, but the screen can only use like 1920x800 (or similar) because the screen is wider than the projector's aspect ratio?

[mojave]

Yes, exactly. The screen is approximately 1920x817. This means that all with an aspect ratio wider larger than 2.35 should have a width of 1920. Those with an aspect ratio of 2.35 or smaller should have a height of 817.

This is a constant image height (CIH) setup. The last 4 home theaters I have been in have been a constant height setup. Two of them had a project that automatically compensated, but the other two need manual changes.

If one could specify their projector screen aspect ratio in Options > Video that would work. JRiver would already know their desktop resolution so a setting of 2.35 would mean a height of 817 pixels for 1080p and 455 pixels for 720p. However, most with a CIH setup have 1080p projectors.

Another alternative is to specify zoom settings per aspect ratio as I mentioned in another thread. In this case, the user would want a 75.6% zoom for 16:9 content and 78.7% for 1.85. I think this method is actually better because it allows the user to dial in any overscan that they might need.

[Matt]

If this is common, we should add an option for it.  It's sort of aspect ratio correction and sort of aspect ratio mode, so I'm not sure where it goes exactly.

Basically it's just a rule that says "don't use more than 817 pixels high of my display".  Does the position of the 817 pixels vary (top, bottom, center)?

I'm a little surprised this is common, because you'd have to watch regular 1080p 16x9 content at 1452x817 with your 1920x1080 projector.  It seems a little weird to throw away so much resolution.

[Hendrik]

I never understood such setups myself. Usually you have the spare height to make a full 16:9 setup, and more movies then you think actually come with full 16:9 picture, and TV shows generally do, so meh. Maybe i'm just missing something.

[mojave]

There are 3,214+ threads and 57,302+ posts in the 2.35:1 Constant Image Height Chat forum at AVS so I would say it is fairly popular. Here is a recent thread about how to handle it with an HTPC. CIH was a large selling point for Theatertek software back when it came out.

Basically it's just a rule that says "don't use more than 817 pixels high of my display".  Does the position of the 817 pixels vary (top, bottom, center)?

I think that would be correct. The position is always centered normally, but some may have their projector mounted so they always use the bottom or top areas of their image. For example if someone ceiling mounted their projector they might always want to use the bottom of their image area for display since it matches up with their seating arrangement and eye level to the screen. Centered might make the image too high so they want to shift the image down.

They handle the image in three ways:

1.  Anamorphic lens with no loss of resolution
2.  Zoom the lens on the projector (manual or automatic) depending on aspect ratio- no loss of resolution
3.  Zoom the image with playback software or device with loss of resolution

I essentially have a 720p projector (1280x768) and hardly notice any pixels on my screen. Those using #3 above with 1080p and "throwing" away pixels still have more than I do. I don't really think it is that noticeable.

I never understood such setups myself. Usually you have the spare height to make a full 16:9 setup, and more movies then you think actually come with full 16:9 picture, and TV shows generally do, so meh. Maybe i'm just missing something.

Those that have these screens usually have the screens as high as they can be in their room and then they add the width for 2.35:1. Below is an example of one room with a 158" diagonal screen. He is still 124" diagonal with 16:9. My screen is 126" diagonal 16:9 so essentially I am losing the width instead of him losing the height since our screens are within an inch in height.

Movie theaters are almost always constant image height. Also, it is easier to mask the side than the top and bottom using either automatic or manual masking systems. I went with a 16:9 screen due to projector and room constraints.

[mojave]

Problem 1
I was back over at nebrunner's house on Tuesday evening. He has been trying VLC, XMBC, MPC-HC, Media Browser and JRiver.

Since has a 2.40:1 screen and the projector only accepts 1080p, you have to use the Nvidia drivers to specify a resolution within a resolution. His ends up being 1920x810x32x60. This is then set as the desktop resolution so he can see all of Window 7 or JRiver within his viewing area. Now he wants to change resolutions to 23, 24, and 59 for use with various video formats. However, instead of having 1920x810x32x23 available, he has 1920x1080x32x23. You can only specify one alternate resolution (to 1920x1080) as showing up as 1080p to the projector.

The problem with using 1920x1080x32x23 that now many of the JRiver menus are off the screen in the black bars above and below his viewing area.

Nebrunner has hundreds of movies in his library and the majority (probably 90%+) are 2.35 or 2.4 aspect ratio so he rarely ever needs 16:9. I would say that my library (with fewer movies) has a similar %.

Solution A
I think an easy solution for those with 2.35:1 screens is for JRiver to allow you to specify that all JRiver content be viewed inside a user specified resolution such as 1920x810x32. The frequency can then be switched and JRiver, including all menus and text, will always show up inside the video area. I say it should be user specified because users make their screens between 2.35 to 2.4 usually and some will even go wider.

Solution B
Make an option so that the OSD always stays within the video area.

Problem 2
A person might shift his image down when the aspect ratio is greater than 2.4:1 so that the bottom of the image always stays at the bottom of the screen. A person with a 16:9 screen, like me, will shift the image down for a 2.35 or wider aspect ratio. By keeping the image at the bottom of the screen you only have to mask the top of the image and, if you don't mask, you still get a better contrast ratio since the bottom of the image is now against the black border.

Solution A
This can be down manually but it really needs a global option. We need to be able to specify shift per aspect ratio so even when a Blu-ray is inserted and played it is in the right position.

[Matt]

It seems like Theater View and Standard View would really need to respect limiting too.

So really the full screen configuration needs to allow saying "use this rectangle of the whole monitor."

If we do this, can we count on nebrunner to buy a $50 license (I'm kidding, mostly)?

[mojave]

Actually nebrunner won a license at the 2011 Subfest in Omaha. He has tried it several times, but keeps going back to XBMC.

I already use JRiver and have the same issue when watching aspect ratios wider than 16:9. The option really should be "Keep JRiver within video area." The option "use this rectangle of the whole monitor" doesn't sound like it moves if I shift the image.

If I shift the video image up or down on the screen I want JRiver to move with it. Since I have a retractable screen, my screen drops all the way for 16:9 movies. For wider than 16:9 movies I move my screen up. However, I'm not precise in the amount of movement and may do it differently for Ben Hur (very wide) vs a 2.35 movie. My resolution is always 1920x1080. After moving the screen up some, I then shift the image down so the bottom of the image is at the velvet around the screen. I can mask the top of the screen and now I essentially have a screen the same size as my video area even though the resolution is still 1920x1080.

Regarding video position, I found out that I can set the Playback Info tag for Auto-Import so that any new movies already are positioned where I want for a starting point. However, the Auto-Import doesn't work for inserted Blu-rays even if I add the drive as a watched folder. Could it be possible to have tags automatically applied to inserted Blu-rays so their position is also correct?