Time duration of content

Applicable protocol:: MIME (http://www.rfc-editor.org/rfc/rfc2045.txt)
Status:: standards-track
Author/Change controller:: IETF (mailto:iesg@ietf.org)
Internet Engineering Task Force.
Specification document(s):: http://www.rfc-editor.org/rfc/rfc2424.txt
Related information:: Time duration of body part content, in seconds (e.g. for audio message).