Lower resolution HDTV receivers
Method and apparatus for changing resolution by direct DCT mapping
Frequency domain filtering for down conversion of a DCT encoded picture
ApplicationNo. 627916 filed on 07/28/2000
US Classes:375/240.27, Error detection or correction375/240.12, Predictive375/240.21, Subsampling375/240.25Specific decompression process
ExaminersPrimary: Britton, Howard W.
International ClassesH04N 007/30
AbstractA downsampling apparatus converts a received DCT coefficient macroblock to a reconstructed pixel block and includes an IDCT module that performs an inverse DCT on the received DCT coefficient macroblock to produce a first intermediate block. A horizontal downsampler horizontally downsamples the first intermediate block to produce a second intermediate block. A calculation module calculates first and second errors. The first and second errors are calculated based upon a difference between the first intermediate block and first and second downsampled/upsampled versions of the first intermediate block derived from corresponding first and second vertical downsampling filters. A filtering module vertically downsamples the second intermediate block using the first or second vertical downsampling filter depending upon whether the first or second error is smaller. A motion compensator adds prediction reference pixels to the horizontally and vertically downsampled block, as appropriate, to form reconstructed pixels.