To configure the media attributes to be broadcast, follow these steps :
Open the channel management page and edit your product distribution channel, not your media channel.
Once you’re in the channel settings, click on the “Attributes” tab, then on the “Media” section. Once you’ve expanded the “Media” section, simply tick the attributes you want to display on your portal.
Finally, go back to your brand portal. On the admin page, open the ‘Content’ tab and click the ‘UPDATE CONTENT’ button.
After that, your media attributes should be visible on the portal.