Captions appear as an overlay to the video asset in the muted state and will disappear in the un-muted state. You can add a caption file to youe videos via the Gemini UI, API and Bulk.
Gemini simply sends the video + caption file in all ad responses. The supply endpoint will play the caption file if it can and, if not, it will play the video without captions (i.e., the status quo).
Follow these steps:
Create a new ad, entitled Wonder Woman, from the Ads & keywords menu and choose the ad format as Video.
The panel for the Video ad appears.
In the Ad details panel, under Upload Video, drag and drop the video that you’ve created into the Video pane from your desktop, in this case, Wonder Woman.mov.
While the video is loading, you can upload the Large rectangle image (which is required) into the image pane. The Square image will populate automatically. Ensure that these images are 1200x627 pixels and 627x627 pixels, respectively, according to image specification requirements.
Select and open your Wonderwoman.srt caption file on your desktop, which includes your captions for the images and follows the defined specs for each image (shown below in the section on supported file types), drag and drop the Wonderwoman.srt caption file on the blank video screen.
Click the view caption item at the bottom of the video.
Enter the text for the Ad title and Ad description, along with your Company name and the Destination URL.
In the Call-to-action button, enter in this case: Watch Now.
Pause the video, save the ad and you’re good to go.