This figure shows how MPEG systems have evolved over time. This diagram shows that the original MPEG specification (MPEG-1) developed in 1991 offered medium quality digital video and audio at up to 1.2 Mbps, primarily sent via CD ROMs. This standard evolved in 1995 to become MPEG-2 that was used for satellite and cable digital television along with DVD distribution. The MPEG specification then evolved into MPEG-4 in 1999 to permit multimedia distribution through the Internet. This example shows that work continues with MPEG-7 for object based multimedia and MPEG-21 for digital rights management.