Render video from a ultra large resolution image

Here's what I do, and I've done a bunch of this kind of thing. You make a bunch of copies of the original image that are about twice as wide as your comp and crop them accordingly so that your push-in effective scale is from 50% to 100% on each image. That might be hard to visualize so I'll give you a step-by-step that is pretty easy to follow.

• Open Photoshop and your original High Rez image
• Save a copy of the original file as a PSD to keep as the master
• You are going from about 10,000 pixels wide to about 2,000 so three or four cropped and resized new files will need to be created - go ahead and make the new files.
• In the Master PSD, the one that is 10,000 pixels wide, select the image layer and copy or drag it to one of the new files you have created
• In the new file, the one that is 4,000 pixels wide, press Ctrl/Cmnd + t to transform the layer that is the copy of the original. Scale it down until it fits the entire frame of the new image
• Delete the background layer because it is no longer needed and save the first new file as Full Frame. This is where you will start your animation.
• Repeat the process with different levels of scale applied until you get to the last copy, which will not be scaled.

You now have 3 or 4 copies of the original image that are only twice as large as your master, each with a different crop. All you have to do is stack them up on top of each other or arrange them in 3D space so that they perfectly overlap (checking with the difference blend mode) and then cut between the images as you scale them or move the camera. 

This does two important things. The resampling as you shrink the image to fit the frame for the wide shot is much better in Photoshop than it is in After Effects, so you get a cleaner image. Second, it limits the number of pixels that After Effects has to resample from 10,000 to the final size to a maximum of twice the comp size, speeding up the render, reducing the memory requirements, and giving you a better result. 

I once did this with a composite of Yosemite valley that came from 24 images from a Sonny A7RIV camera and a 700mm Lens. The resulting panorama was the equivalent of shooting with about a 20mm lens, but the workflow let me push in on a closeup of Yosemite falls with no problem at all and no discernable quality problems. The original panorama was a little more than 45000 pixels wide. That's wider than After Effects could handle, but reducing the wide shot to about 2500 pixels made the project easy. I think I had about eight or ten cropped layers. I should do a tutorial someday. Maybe I will the next time I have a project like that. 

The first thing is to know if you need that resolution for the output file. What is your target? If you don't need such a huge output resolution, you can place your image into a HD or UHD composition where you can maintain the quality when zooming.