Originally committed as revision 22322 to svn://svn.ffmpeg.org/ffmpeg/trunk

Since this function isn't in the public API, it should have an ff_ prefix.

Originally committed as revision 22321 to svn://svn.ffmpeg.org/ffmpeg/trunk

This ensures proper escaping of numerical IPv6 addresses.

The RTSP (de)muxer needs its own network initialization, since it isn't
a protocol and url_open hasn't been called yet.

Originally committed as revision 22226 to svn://svn.ffmpeg.org/ffmpeg/trunk

Originally committed as revision 17159 to svn://svn.ffmpeg.org/ffmpeg/trunk