Video treatments work differently than the traditional static treatments in Marpipe. Instead of assigning different treatments to your Meta ads you will be adjusting the settings on the ad in Meta in order for the video treatment to be automatically used instead of other media.
Here is what to do
Prerequisite: You have video DPA designs published into your video treatment and your video treatment is in an output feed that is actively connected to a Meta Catalog.
Step 1: Create an ad that is using your catalog as the creative source in Meta.
Step 2: Go to Ad Creative and make sure Dynamic Media is enabled
Step 3: Keep Automatic video cropping off
(Optional) Step 4: In the customize settings you may see an option to prefer video if it's available. Make sure that it is turned on if you see it. This option is only available for Single Image/Video Format under Ad Setup, not Carousel
Step 5: Publish your ad.
The ad should now use videos if they are available and you should see the video present in most of the ad placement previews.
If Dynamic Media is enabled on any other catalog ad you are running, your videos will appear there as well. These videos are not explicitly assigned to ads, but rather accessed via Meta's creative options