The process of troubleshooting video metrics and CDN logs can be likened to searching for lost toys, as both involve navigating through complex systems in search of a specific cause or item. In the case of video metrics and CDN logs, server-side errors may impact playback experiences, but it's difficult to know which ones actually had an impact on the viewer’s experience. Common Media Client Data (CMCD) has emerged as a solution to this problem by providing a standard way of passing some standardized data from the player to the CDN, enabling teams to get end-to-end visibility into their viewer experience and resolve issues more effectively. Many major CDNs already support or are building features for CMCD, making it an increasingly valuable tool in improving video playback experiences.