Aspect Ratio

[hydrax]

I'm trying to mix 4:3 footage with 16:9. I'm also resizing all the sources to a 640x360 square pixel ratio to make everything widescreen, of course I cropped the 4:3 footage before resizing it.

One of my sources is:

- Width : 1280 pixels
- Height : 688 pixels
- Aspect ratio : 1.860

So how do I deal with this source to make it a 16:9 aspect ratio.

My second source is:

- Width : 1920 pixels
- Height : 1040 pixels
- Aspect ratio : 16/9

and it's also letterboxed. How do I remove the letterboxing and resize it to 640x360 correctly?

Thanks for any help that may be offered

[Willen]

Hmm. Your first source seems to be cropped a little on the top and bottom, assuming it is a 1.85:1 aspect ratio film like many live-action Hollywood movies are, making the 1.86:1 AR still close to the standard 1.85:1. What most movie companies do when transferring 1.85:1 AR films to DVD which has a 1.78:1 AR is to add small black bars (letterboxes) to the top and bottom. I assume many encoders who distribute films online crop the additional letterboxes off and a little of the actual movie footage to get the resolutions to multiples of 16 (mod16) for better compression. Thus, we end up with slightly odd resolutions instead of the usual 1280 x 720 for 16:9 AR material.

As for your second source, how much letterboxing are we talking about? 1920 x 1040 equates to a 1.846:1 (1.85:1 rounded up) AR with mod16 resolutions. Normally, 1920 x 1080 is the standard resolution for 16:9 material, BUT 1080 isn't mod16. Many times you'll see the videos as 1920 x 1088 resolution which is mod16, but isn't exactly 16:9 AR. If we are using a mod8 compatible codec, then 1080 is fine. But I digress...

For consistency sake, you'll want to not have any letterboxing in any of your footage. This means you may want to resize the videos to the same height as your other footage, then trim a bit of the videos on the sides to bring it to 16:9 AR.

Resize the 1280 x 688 video to (1280 / 688 = 1.8604651 x 360 = 669.76743) 670 x 360, then crop 15 pixels from both sides (for a total of 30). This should leave you with a final video resolution of 640 x 360.

The 1920 x 1040 video is trickier. You'll probably want to eliminate all the letterboxing, then resize the video to match your target height of 360 pixels, and finally crop the sides. If the video ends up with a wider aspect ratio than 1.85:1 like 2.00:1 or 2.35:1, you may be losing important parts of the video footage from the sides when you crop so be selective on how much you take off from each side.

[hydrax]

I had to resize the first to 680x360 because it wouldn't accept 670x360 and cropped 20 of each side rather than 15. I have a resolution of 640x360 now.

The second was actually less problematic, cropped the letter boxing, resized it and cropped the width again to get to 640x360.

Thank you for the help, really appreciated!