A level is the definitions for the MPEG standard for physical parameters such as bit rates, picture sizes and resolutions. There are four levels specified by MPEG2, High level, High 1440, Main level, and Low level. MPEG2 Video Main Profile and Main Level has sampling limits at CCIR 601 parameters (PAL and NTSC). Profiles limit syntax (i.e. algorithms), whereas Levels limit encoding parameters (sample rates, frame dimensions, coded bitrates, buffer size etc.). Together, Video Main Profile and Main Level (abbreviated as MP@ML) keep complexity within current technical limits, yet still meet the needs of the majority of applications. MP@ML is the most widely accepted combination for most cable and satellite TV systems, however different combinations are possible to suit other applications.