The 2002 release of Flash Player 6 added support for video in the SWF file format. The 2003 release of Flash Player 7 added direct support for the FLV file format. Because of restrictions in the FLV file format, Adobe Systems created new file formats in 2007, based on the ISO base media file format (MPEG-4 Part 12). In this way, the F4V format shares a common base with the MP4 format, which is why F4V is sometimes informally called "Flash MP4". Flash Player does not check the filename extension but instead examines the file to determine the format.