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mattheww25775576
mattheww25775576
Participant
August 24, 2023
Answered

Aspect ratio and anamorphic video

  • August 24, 2023
  • 1 reply
  • 5328 views

Hello,

 

I am currently in post-production on a short film filmed on the Arri Alexa Mini LF using Anamorphic Lenses. The dimensions of the video files are 3424x2202 with a pixel aspect ratio of 2.0. I have a picture lock cut currently that's ready to go to color in DaVinci and the DP had told me that the footage has already been set to be stretched thus I only imported the footage and haven't done anything else with the footage.

 

I was told that this is 2.39:1 but it is way too wide to be that aspect ratio. I've been trying to adjust the aspect ratio and haven't been having luck. Am I doing something wrong on my end or is there a problem in Premiere Pro?

 

Please see images attached indicating the current layout, how the footage looks in the timeline, clip properties, etc..

 

Also, when I export cuts (using proxy files), I see on my Mac the dimensions are 6848x2202

 

Note: The delivery will be 2.39.1 most likely in 4K. 

 

Thank you in advance!

This topic has been closed for replies.
Correct answer Fergus H

Hi Matt!

 

Great question! Handling anamorphic footage can be a little confusing. Here are a few things to consider. 

 

The footage you received is definitely not 2.39:1. It was shot using a recording resolution on the ALEXA Mini LF called “3.4K S35 3:2 - 3.4K”. Not surprisingly, that’s 3:2 aspect ratio, and it has a resolution of 3424 x 2202. 

 

In addition, the Mini LF has a setting called “Lens Squeeze Factor” and for your footage, that was set to 2. (A 2x squeeze is most common for cinema lenses like ARRI Master Anamorphic and Atlas Orion lenses.) Premiere Pro reads the Lens Squeeze Factor metadata and uses that for the Pixel Aspect Ratio. 

 

If you drag a clip with these settings in the timeline, Premiere Pro will create a new sequence with a resolution of 3424 x 2202 and a Pixel Aspect Ratio of 2. Your sequence with have ratio of 6848 x 2202 - way wider than 2.39:1. See the attached “Clip setting sequence” screen capture for what that looks like. Premiere Pro is doing what you tell it to do (i.e., creating a sequence based on your clip) instead of what you need, which is a sequence with the right delivery settings.

 

The sequence needs a pixel aspect ratio of 1 and whatever resolution your customer requires. (Unravel’s Aspect Ratio Cheat sheet is a good resource for aspect ratio and resolution information: https://www.unravel.com.au/aspect-ratio-cheat-sheet.)

 

For the attached “Delivery setting sequence” screen shot, I created a sequence for Cinema DCP 4K 2.29:1, which is 4096 x 1716, and I made sure the Pixel Aspect Ratio was 1. The clip I put onto that sequence was shot using the same ALEXA settings as yours: 3.4K S35 3:2 - 3.4K. (Sadly, my clip is a very sad shot of a mostly-empty office!)

 

In the “Delivery setting sequence” screen shot, I’ve double-clicked on the clip in the Program Monitor to show the area of the clip versus the area of the sequence. 

 

Lastly, make sure that Preferences > Media > Default Media Scaling is set to None. It is by default but check it, as it’s important that Premiere Pro does not automatically scale your media. 

 

I hope this helps and, of course, let me know if you’ve got any other questions. Perhaps I’ll use it as an excuse to shoot some more interesting test footage!

 

Regards,

Fergus

1 reply

Fergus H
Community Manager
Fergus HCommunity ManagerCorrect answer
Community Manager
August 25, 2023

Hi Matt!

 

Great question! Handling anamorphic footage can be a little confusing. Here are a few things to consider. 

 

The footage you received is definitely not 2.39:1. It was shot using a recording resolution on the ALEXA Mini LF called “3.4K S35 3:2 - 3.4K”. Not surprisingly, that’s 3:2 aspect ratio, and it has a resolution of 3424 x 2202. 

 

In addition, the Mini LF has a setting called “Lens Squeeze Factor” and for your footage, that was set to 2. (A 2x squeeze is most common for cinema lenses like ARRI Master Anamorphic and Atlas Orion lenses.) Premiere Pro reads the Lens Squeeze Factor metadata and uses that for the Pixel Aspect Ratio. 

 

If you drag a clip with these settings in the timeline, Premiere Pro will create a new sequence with a resolution of 3424 x 2202 and a Pixel Aspect Ratio of 2. Your sequence with have ratio of 6848 x 2202 - way wider than 2.39:1. See the attached “Clip setting sequence” screen capture for what that looks like. Premiere Pro is doing what you tell it to do (i.e., creating a sequence based on your clip) instead of what you need, which is a sequence with the right delivery settings.

 

The sequence needs a pixel aspect ratio of 1 and whatever resolution your customer requires. (Unravel’s Aspect Ratio Cheat sheet is a good resource for aspect ratio and resolution information: https://www.unravel.com.au/aspect-ratio-cheat-sheet.)

 

For the attached “Delivery setting sequence” screen shot, I created a sequence for Cinema DCP 4K 2.29:1, which is 4096 x 1716, and I made sure the Pixel Aspect Ratio was 1. The clip I put onto that sequence was shot using the same ALEXA settings as yours: 3.4K S35 3:2 - 3.4K. (Sadly, my clip is a very sad shot of a mostly-empty office!)

 

In the “Delivery setting sequence” screen shot, I’ve double-clicked on the clip in the Program Monitor to show the area of the clip versus the area of the sequence. 

 

Lastly, make sure that Preferences > Media > Default Media Scaling is set to None. It is by default but check it, as it’s important that Premiere Pro does not automatically scale your media. 

 

I hope this helps and, of course, let me know if you’ve got any other questions. Perhaps I’ll use it as an excuse to shoot some more interesting test footage!

 

Regards,

Fergus

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