Scroll to the very bottom of a video description and you will often find a short line in square brackets, sitting near the hashtags, that reads something like [PRESENTED BY Company A X Company B]. It is easy to skip, so here is how we read it. A presented-by line names the companies the release is put out under. In practice that tends to be the label side, and it works as a branding credit: it tells you whose name is on the release, not what each name actually did.
The block above it is a different thing. A production-credit block lists the crew and a production company that made the video, such as the people behind direction, camera work, lighting, editing and styling. That is a job list for the video itself. The presented-by line is about the release as a whole. So when you read the two together, treat them as answering two separate questions: who made the video, and whose name the release carries. A production company in the credits and a company in the bracketed line can be entirely different names, and that is normal.
When the line joins two names with an x or X, the release is credited to both. That is all the symbol tells you. It does not by itself say who owns the song, who paid for the video, or how responsibilities are split between the two. Also keep the uploading channel separate in your head. A video can sit on one company's channel while the line names another company, or names both. The channel is where the file was posted; the line is a credit written in the description. They can match, and they do not have to.
To confirm what you are looking at, check a few places. Start with the credit block just above the line, since it spells out the crew roles. Then open the uploading channel's about page to see which company runs it. Finally, look at the act's own announcements for the release, which may word the credit more fully. Be honest about the limits: the phrasing differs from release to release, some descriptions have no such line at all, and the line does not describe anyone's share or role. If it is missing or vague, read it as a name credit and nothing more.