Symbol 5516 from IEC 60417 - Title/Meaning: Picture-in-picture, select Function/description: To identify the control by which a source for a picture-in-picture (PIP) can be selected.
Additional information: 
PIP = Picture-in-Picture.
The triangle may be filled in
Title was editorially improved.,Missing Note (E) was added. (2013-04-03)
Own work using: iso.org/obp/graphics/grs/8fc569c0-cb14-43d4-8c89-87fd3169aef9 200.png
Vectorization:  Mrmw