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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Monitoring 4K Resolution Video

Pixel count

Pixel count

Mike you are right - better to have too many pixels captured in-camera and then crop them to get down to your delivery format / aspects than make your camera originals too format specific. That was a valuable lesson from film brought over to RED. Unless you know the project is for HDTV - in which case you can shoot 1080p or 720p - its best to shoot 16:9 RAW and then scale / crop / apply LUTs from that digital equivalent of a camera negative.
 
For the DCI spec, as far as I know, the image area is 1998x1080 which is 1:85 image. The left over 50 pixels is probably used for something else.

DCI Cinemascope image area would be 2048x858


Also Vistavision (8perf 35mm) isn't normally used for anything except visual effects plates, and is considered 3k 3072x2048 and is 1.5 aspect.
 
Thomas the 1998 x 1080 number you cited for vista vision is just half (each) of the 3996x2160 I quoted in the post above since I was talking 4k (in particular the Sony 4k projector) and you are using 2K numbers. The extra pixels are just those surplused in cropping to 1.85.
 
Thomas Mathai said:
For the DCI spec, as far as I know, the image area is 1998x1080 which is 1:85 image. The left over 50 pixels is probably used for something else. DCI Cinemascope image area would be 2048x858
Click to expand...

Thomas - where do you get that information? The DCI spec and its errata are publicly available at www.dcimovies.com.

From the DCI spec v1.0a, section 3.2.1.2:

"The DCDM [Digital Cinema Distribution Master] shall provide an image structure container that consists of either a 2K (2048 x 1080) or 4K (4096 x 2160) image file as defined in Table 1. It is expected that the image structure shall use one of the two containers such that either the horizontal or vertical resolution is filled. For example, a 4K image file with a 2.39:1 aspect ratio would require an image structure of 4096 x 1714, therefore filling the horizontal resolution of the 4K container...."

Lucas Wilson
------------
ASSIMILATE, Inc.
Los Angeles
 
luki said:
Thomas - where do you get that information? The DCI spec and its errata are publicly available at www.dcimovies.com.

From the DCI spec v1.0a, section 3.2.1.2:

"The DCDM [Digital Cinema Distribution Master] shall provide an image structure container that consists of either a 2K (2048 x 1080) or 4K (4096 x 2160) image file as defined in Table 1. It is expected that the image structure shall use one of the two containers such that either the horizontal or vertical resolution is filled. For example, a 4K image file with a 2.39:1 aspect ratio would require an image structure of 4096 x 1714, therefore filling the horizontal resolution of the 4K container...."

Lucas Wilson
------------
ASSIMILATE, Inc.
Los Angeles
Click to expand...


My assumption is you're always going to have to maintain aspect ratio, no matter what.

Even if it's 2048x1080, that's an aspect of 1.89:1. So you can fill X to 2048, then your Y have to be 1107, which is outside the Y limit of the spec (1080).

If you instead have 50 pixels of black at the left side, and fill to your Y @1080, then your X will be 1998. This means you have a 1.85 image pasted flush right in a 1.89 image.

The spec says the final container image is 2048x1080, but there is no way you're going to want to slighty stretch a 1.85 image to 1.89.

So for 1.85 Academy image, you'd take 1828x988, scale to 1998x1080 and paste flush right to 2048x1080.

I don't know if the extra 50 pixels is used for anything, probably not. I can find out.
 
What graphics cards will work with these resolutions?
 
Thomas Mathai said:
Even if it's 2048x1080, that's an aspect of 1.89:1. So you can fill X to 2048, then your Y have to be 1107, which is outside the Y limit of the spec (1080).
...
So for 1.85 Academy image, you'd take 1828x988, scale to 1998x1080 and paste flush right to 2048x1080. ...
Click to expand...

Ah - ok, I get what you're saying. I thought you were saying that the DCI output was 1998. Yeah, you're right - 1.85 within DCI would be 1998.

I just posted a question to the CML-2K - I'm curious what 35mm cinematographers are doing (if anything) to accomodate for DCI. Common-top?

Regards,

Lucas Wilson
------------
ASSIMILATE, Inc.
Los Angeles
 
luki said:
Ah - ok, I get what you're saying. I thought you were saying that the DCI output was 1998. Yeah, you're right - 1.85 within DCI would be 1998.

I just posted a question to the CML-2K - I'm curious what 35mm cinematographers are doing (if anything) to accomodate for DCI. Common-top?

Regards,

Lucas Wilson
------------
ASSIMILATE, Inc.
Los Angeles
Click to expand...

I think anyone encoding for DCI is going to accomodate the cinematograhers at the moment.

Most should be straight forward. Though I wouldn't be surprised if there are some funky resizing going on.
 
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