The chromecast.xml file included with a Plex Media Server installation represents a baseline of support for a device; in this case it represents the first-generation Chromecast.
When the Plex Chromecast receiver is instructed to play a media stream, it first checks its own capabilities, and those of the display to which it’s attached, such as maximum resolution, on-device codec support, and audio passthrough capabilities. It uses those checks to create an augmentation to the Chromecast.xml profile. For example, although EAC3 passthrough is not expressed in Chromecast.xml, the transcoder will allow it to direct stream when the capability is expressed in the profile augmentation.
I’m working on making Chromecast device logs available through the Plex Media Server logs in a way that won’t adversely affect device performance. I’ll include information in the Chromecast release notes once such a feature goes live.
