crop has no effect

[marcelmax]

Hi,

i have a 1:1,85 film with letterbox as DCP. when I put container and contents on scope and crop 67 vert and 22 hor picture looks fine. After rendering I open in DCP o matic player and video is stretched with bars on all sides like if the crop did not have any effect. Have reproduced several times. Always the same.
Anyone an idea?

Went back to 2.10.5. and problem was gone. But the crop numbers had to be twice as high as in the recent version of DOM

Now I fixed a little remaining letterbox in another dcp the same way. I am quite sure now, crop is not working correctly. When you increase crop until the black bars disappear they will still be in in the rendered dcp. This issue was not in 2.10.5. Maybe the crop number has to be doubled in 2.12 ???

[Carsten]

Oops... you are right. There seems to be a major flaw with the cropping in 2.13.x...

Stay tuned, I'll try to recplicate that with the same project from 2.10.5 through 2.12 ... and 2.13.x ...

- Carsten

.... previous text ....
Can you show us some screenshots?

What does 1.85 with letterbox mean? Do I understand right that you want to convert a letterboxed scope content into a 'real' scope DCP?

In that case, load DCP, set scale to 'Scope' (2.39), and container to Scope. Then crop away the black bars from top and bottom. If your letterboxed scope has 'real' scope AR, it should be approx 1998*835 active pixels. That means, you should probably crop away approx 122 pixels from both top and bottom (1080-836).

The preview window in DCP-o-matic should show a full frame scope image without any black bars. It should play just the same in player (and cinema).

If you have black bars all around the image, I can only assume you left scale to at flat/1.85, not scope.

- Carsten

[Carsten]

Yup - the cropping numbers are internally doubled for the preview - 2.10.5 does it right, 2.12.3 does it wrong. That means, when I load a project created with 2.10.5, with a cropping of 122pix top and bottom into 2.12.3, it is (at least visually) cropped twice as many pixels (244 from both top and bottom). So, in this case, the scope preview is stretched heavily top to bottom. The number display under content shows the correct cropping, but the preview is wrong.

Now, when I actually try to create that DCP...

Yup - DCP-o-matic does everything right creating the DCP, applying the right cropping, but the preview in DCP-o-matic is visually wrong...so you can't crop visually based on the preview image, but only based on calculated numbers. Or use 2.10.5 for now.

@Carl: What a nasty one! How did that one escape us?

It seems though, that this only happens for DCPs as source footage. I tried to reproduce the same preview with a still image grabbed from the same DCP (letterboxed scope in flat), and it didn't happen. I will create an MP4 version to find out wether other types of video are also hit by this.

edit: Nope, it doesn't happen for MP4, so it maybe only for DCPs...now, does it happen for J2K-MXF...yes, so I guess it's safe to say it hits DCP/MXF files.
When I create a DCP with a cropping that appears visually okay in preview, the resulting DCP is letterboxed, there remain black bars on top and bottom.



- Carsten

[marcelmax]

this looked perfect in DOP. no bars and no stretching

[marcelmax]

thanks
Hope, it will be fixed soon...

[Carsten]

Carl has recognized this bug - it's hard to catch, since it is 'only' a preview defect. Unfortunately, most people understandably prefer to crop by looking at the preview, so, the preview-only defect turns into a bad DCP.

Worse, it only happens with small preview window sizes. If you are working on high-res monitors, the preview should look okay under the same conditions.

As it is still a serious issue, Carl is about to implement the fix both in 2.13 test as well as 2.12 stable.

- Carsten

[Carsten]

2.12.4 stable is online and should correct that issue. It does for me.

- Carsten