[matt4077]

I'm trying to think of an open source project that is used as widely as VLC, and not backed by Google. Maybe there is, but I can't think of any.

[Manozco]

SQLite

[ars]

ffmpg/libav - even VLC itself uses it.

[sametmax]

Cups

[sametmax]

Zlib

[indubitable]

apache http server

[rakoo]

curl