Abstract: An HDTV down conversion system including an apparatus for forming a low resolution 2:1 down converted video signal from an encoded video signal representing a video image. The encoded video signal is a frequency-domain transformed high resolution video signal with motion prediction. The apparatus includes a receiver for receiving encoded video signals as a plurality of high resolution frequency-domain video coefficient values. A down conversion filter receives and weights the high resolution frequency-domain video coefficient values to form a set of low passed frequency-domain video coefficients. An inverse-transform processor transforms the set of frequency-domain video coefficients into a set of pixel values. An averaging filter transforms selected ones of the pixel values in the set of pixel values into averaged pixel values. A decimating processor deletes selected ones of the set of pixel values to provide the low resolution video signal.

Abstract: An HDTV down conversion system including an apparatus for forming a low resolution 2:1 down converted video signal from an encoded video signal representing a video image. The encoded video signal is a frequency-domain transformed high resolution video signal with motion prediction. The apparatus includes a receiver for receiving encoded video signals as a plurality of high resolution frequency-domain video coefficient values. A down conversion filter receives and weights the high resolution frequency-domain video coefficient values to form a set of low passed frequency-domain video coefficients. An inverse-transform processor transforms the set of frequency-domain video coefficients into a set of pixel values. An averaging filter transforms selected ones of the pixel values in the set of pixel values into averaged pixel values. A decimating processor deletes selected ones of the set of pixel values to provide the low resolution video signal.

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.

Abstract: A video down conversion system compliant with the Advanced Television Systems Standard (ATSC) includes a decoder which decodes a Main Profile, High Level (MP@HL) image and employs a downconversion processor to produce a standard definition video signal. The system stores a subsampled image in order to reduce memory requirements and employs an upsampling filter to generate reference image data from the stored. subsampled image. The reference image data spatially correspond to the image data produced by the video decoder before it is subsampled. The upsampling filter uses different filter coefficients based on the subsampling phase of the stored image and the half-pixel indicator in the motion vector which is used to locate the downsampled reference image data in the stored subsampled image.