MPEG

Set to 2 different clues across 2 published puzzles, most often “Compressed video file format” — The New York Times, Thursday, 19 May 2011.

4 letters

Every clue on record, most used first

Compressed video file formatonce
The New York Times — Thursday, 19 May 2011
Compressed electronic file formatonce
The New York Times — Thursday, 2 June 2005