Abstract: A video decoder compliant with the Advanced Television Systems Standard (ATSC) includes circuitry which, when the decoder is operated in a first mode, decodes a Main Profile, High Level (MP@HL) image to produce a high-definition video output signal and decodes a Main Profile, Main Level (MP@ML) signal to produce a standard definition video signal. In addition, when the decoder is operated in a second mode, circuitry is used which generates a standard definition image from the MP@HL signal. The video decoder includes a frequency-domain filter to reduce the resolution of the MP@HL signal when the decoder is operated in the second mode.

Abstract: A video memory system for storing ATSC video image data is configured as three channels, each channel having two banks and each bank including a plurality of memory rows. The exemplary memory system includes a buffer area for holding bit-stream data and six field buffer areas. The field buffer areas are arranged in pairs to form a three frame buffer areas, such that the buffer areas for the two fields in a given frame are allocated in respectively different banks. The video memory system includes an output memory controller which receives macroblocks of decoded image data and divides the received macroblocks into respective upper and lower half-macroblocks, the upper half-macroblock being stored in one field buffer of the frame and the lower half-macroblock being stored in the other field buffer of the frame.