The MPEG-2 Standard is published in four parts. It defines a multiplexed structure for combining audio and video data and means of representation the timing information needed to replay synchronized sequences in real time. A Header and a series of one of more pictures intended to allow random access into the sequence. The primary coding unit of a video sequence. The Y matrix has an even number of rows and columns.
Slice are important in the handling of erros.
If the bitstream contains an error, the decoder can skip to the start of the next slice. Having more slices in the bitstream allows better error concealment, but uses bits that could otherwise be used to improve picture quality. The basic coding unit in the MPEG algorithm. It is a 16x 16 pixel segment in a frame. Since each chrominance component has one-half the vertical and horizontal resolution of the luminance component, a macroblock consists of four Y, one Cr, and one Cb block.