How to pass SMPTE KLV metadata in a pipeline

[Josh Doe]

I'm interested in what might be the best way to pass SMPTE KLV
(http://en.wikipedia.org/wiki/KLV) metadata in GStreamer. There are
already several elements that could be producing/consuming KLV data
(mxfmux, mxfdemux, mpegtsmux, mpegtsdemux). It would be nice to have a
standard way of communicating this data, so these and other elements
can interoperate. Perhaps KLV packets can be sent as their own stream,
or as events? Anyone else interested in this?

-Josh