d07c04d7____GStreamer_SDK_documentation__since_the_start_of_the_program
Name of the object that issued the message. It can be an element, a Pad, or something else. Useful when you have multiple elements of the same kind and need to distinguish among them. Naming your elements with the name property will make this debug output more readable (otherwise, GStreamer assigns each new element a unique name).
Basic tutorial 11: Debugging tools - GStreamer SDK documentation - GStreamer SDK documentation
Time stamp in HH:MM:SS.sssssssss format since the start of the program