Does anyone know whether I could perform HTTP requests from the YT Data API, asking for an actual mp4 file of a video that has been uploaded to a specicific channel that has granted me access to do so via OAuth2? I would need the mp4 file because I want to subtitle the videos I pull from those channels.
I read the docs, but I wasn't able to find any details on this matter, unfortunately.
Unfortunately there isn't any YouTube Data API v3 Videos: download endpoint as there is the Captions: download one. I would recommend you to use yt-dlp to download your videos in an automatic manner.