H.264 Profiles and Levels
The joint group involved in defining the H.264 standard has focused on creating a simple and clear solution that minimizes options and parameters.
The most important aspect of this standard, as is the case with other video standards, is the provision of various capabilities within profiles (sets of algorithmic parameters) and levels (performance classes) to optimally support popular products and common formats. .
There are seven profiles in H.264, each of which is tailored to a specific application. Each profile determines which set of parameters the encoder can use and limits the complexity of the decoder implementation.
Network cameras and video encoders are likely to use a so-called baseline profile, designed primarily for use in areas with limited computing power. The baseline profile is best suited for use in modern real-time encoders embedded in network video equipment. This profile also provides low latency, which is an important requirement for video surveillance, and is essential for real-time control of pan, tilt and zoom of network PTZ cameras.
H.264 has 11 levels or degrees of limitation in terms of functionality, bandwidth, and memory requirements. Each level defines the bit rate and encoding rate in macroblocks per second for resolutions ranging from QCIF to HDTV and beyond. The higher the resolution, the higher the required level.
