crop node, or other ways to crop TBH project

what’s the best way to crop a project when exporting a movie file, for example, working in a 1920 x 1080 scene, creating an animated element that measures only 400 x 400, and then trimming away the excess for a 400 x 400 movie file, still at the orig resolution (without “resampling”)?

i’ve been reading up on, and testing, the crop node, but there’s not enough info in the docs or online on how to actually export at the size set in the crop node settings where x and y and offset info is entered.
if you then export using the movie settings, the file gets resampled (for example: at “full res”, 400x400 gets blown up distorted to 1920 x 1080, and even “custom” seems to only allow the same pixel aspect ratio of the orig rectangular 1920 x 1080, only smaller).
if you export with the"write nodes" there’s no movie file option, only still frame sequences.

ideas?

Make sure you have what you want to export plugged into a composite node. Below that, hook up the Crop Node. Below the Crop Node, hook up the Write and Display nodes. Select the Crop Node. In Layer Properties, type 400 x 400 or whatever dimensions you want. Now, if you choose ‘Draw Frame’ in the properties and then if you select the Render View for your Camera Window (as opposed to the Open GL View), then you should see the hairline crop box. You can make the crop box line a different color. By default, it is white, so you may not see it if your render window has a white background/colour card. With your Crop node selected AND the Render View active, you can use the Animate Current Frame or Animate Off (All Frames) button to move the crop box around. Note you will not see this box in Open GL View. If you have a character or something you want to scale up, simply add a peg above your character and use Animate Off to scale your character or prop up to fit optimally inside your Crop box. Make sure you have adjusted your Write node to be what you want. In the Write properties, I like to export PNG4 as the image type (which will support transparency). If you hit Ctrl Shift Y or Cmd Shift Y, you’ll be able to do the Render Write Nodes command. Your frames or movie should export to your Frames folder inside your project. What if your frames still come out 1920x1080? I am on Windows 10 and the Crop node is extremely glitchy. Sometimes it works and sometimes it doesn’t. I find that if I delete the previous Crop node, drag a new one in from the Node Library and type the properties in that I want, it will usually work. I find it has problems exporting if I have used the Animate Current Frame or Animate Off tools. Good luck!

BTW, the Write Node has the option to checkmark ‘Movie’ if you want to export a movie file. DO NOT Go up to File\Export\Movie. I have had problems with Harmony creating undeletable movie files and was told to always use the Render Write Nodes command.