Wikipedia
KLV
KLV (Key-Length-Value) is a data encoding standard, often used to embed information in video feeds. Items are encoded into Key-Length-Value triplets, where key identifies the data, length specifies the data's length, and value is the data itself. It is defined in SMPTE 336M-2007 (Data Encoding Protocol Using Key-Length Value), approved by the Society of Motion Picture and Television Engineers. Due to KLV's large degree of interoperability, it has also been adopted by the Motion Imagery Standards Board.