The log level as string. See mpv_request_log_messages() for possible values. The level "no" is never used here.
The same contents as the level field, but as a numeric ID. Since API version 1.6.
The module prefix, identifies the sender of the message. As a special case, if the message buffer overflows, this will be set to the string "overflow" (which doesn't appear as prefix otherwise), and the text field will contain an informative message.
The log message. It consists of 1 line of text, and is terminated with a newline character. (Before API version 1.6, it could contain multiple or partial lines.)