Alexa 35 Anamorphic DeSqueeze in post

[peter.lundgren]

Prepping a project for online and grade that is shot on the Alexa 35 with 2x anamorphic lenses.
4.6K 3:2 OpenGate - 4608 x 3164 px
Not de-squeezing in camera but rather in Resolve.

Recent anamorphic projects I have - and been recommended - to de-squeeze the image horizontally giving me - in this case - a ratio of 6:2 and a resolution of 9216 x 3164 px
Keeping the original height but stretching the width 2x
It feels weird to stretch the recorded image 200%...

Or is the correct way to keep the width and squeeze the height 50% to a 4608 x 1582 image?

I know a we're aiming at a 2,35 delivery but client is asking for a standard 16:9 UHD without letterbox.
Also want to keep the option of being able to deliver different SoMe-formats if needed.
So the more height resolution we can keep the better.

Weird thing is that is that the Adobe apps (Premiere & After effects) are doing the squeeze differently then Resolve.

All clips are interpreted to PAR 2.0

PP and AE does the desqueeze horizontally - keeping the height and double the width.

Resolve does the opposite and keeps the width and does 50% of height.

[LynnSingleton]

So, I’m working on a project shot with the Alexa 35 using 2x anamorphic lenses at 4.6K 3:2 OpenGate (4608 x 3164 px), and instead of de-squeezing in-camera, I’m doing it in Resolve.

What’s puzzling me is how to properly handle the de-squeeze. Some recent projects I’ve been advised to stretch horizontally, giving me a 6:2 ratio and a resolution of 9216 x 3164 px, which feels odd since I’m stretching the image by 200%. Or, should I keep the width and squeeze the height by 50% for a 4608 x 1582 image?

The client wants a 16:9 UHD deliverable without letterboxing, but I also want flexibility for different SoMe formats. Interestingly, Adobe apps like Premiere and After Effects handle de-squeezing differently than Resolve. Premiere and AE double the width, while Resolve keeps the width and halves the height. Feels like they’re not on the same page, right?

[Jan Heugel]

Hi Peter & Lynn,

yes, there are two ways. If we start with 4.6K 3:2 OpenGate - 4608 x 3164 px, for simplocity we want to do a DCI 2.39 within UHD (letterboxed, final resolution: 3840x1608).

1) de-squeeze horizontally / "stretch"
4608 x 3164 px -> 9216 x 3164 px > downscale to 4684 x 1608 (Factor: 1,9675491033) > crop to 3804x1608

2) squeeze vertically
4608 x 3164 px -> 4608 x 1582 px > upscale to 4684 x 1608 (Factor: 1,01643489254) > crop to 3804x1608

Both way yield almost similar results. The difference may show in details, but will vanish immediately if we're talking about a moving image (As you cannot differentiate a 2K pan va. 4K pan).
Please conduct your own tests.

Best regards,
Jan

[peter.lundgren]

Hi Peter & Lynn,

yes, there are two ways. If we start with 4.6K 3:2 OpenGate - 4608 x 3164 px, for simplicity we want to do a DCI 2.39 within UHD (letterboxed, final resolution: 3840x1608).

1) de-squeeze horizontally / "stretch"
4608 x 3164 px -> 9216 x 3164 px > downscale to 4684 x 1608 (Factor: 1,9675491033) > crop to 3804x1608

2) squeeze vertically
4608 x 3164 px -> 4608 x 1582 px > upscale to 4684 x 1608 (Factor: 1,01643489254) > crop to 3804x1608

Both way yield almost similar results. The difference may show in details, but will vanish immediately if we're talking about a moving image (As you cannot differentiate a 2K pan va. 4K pan).
Please conduct your own tests.

Best regards,
Jan

Hi Jan, thanks for a clear answer!
Tried to get an answer in different forums but only getting vague replies.
Ok. Interesting.
So it´s more of a "If it looks good it's ok?"
So i could – in theory – go route 1 if I want a UHD 3840x2160 16x9 delivery.
Just downscale and crop the 9216 x 3164 px > downscale to 6292 x 2160 > crop to 3840 x 2160?
As long as it looks ok?

[peter.lundgren]

So, I’m working on a project shot with the Alexa 35 using 2x anamorphic lenses at 4.6K 3:2 OpenGate (4608 x 3164 px), and instead of de-squeezing in-camera, I’m doing it in Resolve.

What’s puzzling me is how to properly handle the de-squeeze. Some recent projects I’ve been advised to stretch horizontally, giving me a 6:2 ratio and a resolution of 9216 x 3164 px, which feels odd since I’m stretching the image by 200%. Or, should I keep the width and squeeze the height by 50% for a 4608 x 1582 image?

The client wants a 16:9 UHD deliverable without letterboxing, but I also want flexibility for different SoMe formats. Interestingly, Adobe apps like Premiere and After Effects handle de-squeezing differently than Resolve. Premiere and AE double the width, while Resolve keeps the width and halves the height. Feels like they’re not on the same page, right?

?
Are you just repeating my question but with different words?

[Jan Heugel]

I guess another KI-bot. Sometime they add spam links, sometimes it makes 50% sense

[Jan Heugel]

Hi Jan, thanks for a clear answer!
Tried to get an answer in different forums but only getting vague replies.
Ok. Interesting.
So it´s more of a "If it looks good it's ok?"
So i could – in theory – go route 1 if I want a UHD 3840x2160 16x9 delivery.
Just downscale and crop the 9216 x 3164 px > downscale to 6292 x 2160 > crop to 3840 x 2160?
As long as it looks ok?

Sure. Nobody will protest.

I tried the most simple approach: going both ways via MacOS' preview, here is the result: https://f.io/sAl4VVV3. At 500% you see differences in the details (e.g. label on the compressor).
This is a difference image with 50x gain applied:

diff_image_sawmill.jpg

Cheers,
Jan

[peter.lundgren]

Thanks again!!
It really answers my question!
Thanks for the images!
Have a great day
/Peter