US 6,665,344 B1 · Downconverting decoder for interlaced pictures

Abstract

Received frame and field coded DCT coefficient blocks are downconverted to lower resolution reconstructed pixel field blocks so that, for example, HDTV programs can be played on NTSC receivers. The frame and field coded DCT coefficient blocks have motion vectors associated therewith. Specifically, the received frame coded DCT coefficient blocks are converted to converted field coded DCT coefficient blocks and an IDCT module is performed on the converted field coded DCT coefficient blocks to produce downconverted field residual or pixel blocks. Also, an IDCT is performed directly on the received field coded DCT coefficient blocks to produce downconverted field residual or pixel blocks. Reference pixel blocks are selected based upon the motion vectors, the reference pixel blocks are upsampled, and the upsampled reference pixel blocks are downsampled. The upsampled and downsampled reference pixel blocks form predictions that are added to the field residual blocks in order to form reconstructed pixel field blocks.

Claims44

Dependent claims

A method of downconverting received frame and field coded DCT coefficient blocks to reconstructed pixel field blocks, wherein the frame and field coded DCT coefficient blocks have motion vectors associated therewith, the method comprising the following steps:

a) converting the received frame coded DCT coefficient blocks to converted field coded DCT coefficient blocks and performing an IDCT on the converted field coded DCT coefficient blocks to produce residual or pixel field blocks;
b) directly performing an IDCT on the received field coded DCT coefficient blocks to produce residual or pixel field blocks;
c) selecting reference pixel blocks based upon the motion vectors, upsampling the reference pixel blocks, and downsampling at least a portion of the upsampled reference blocks to form a prediction;
and,
d) adding the prediction to the residual field blocks to form reconstructed field blocks.

2 more elements

An apparatus for downconverting received frame and field coded DCT coefficient blocks to reconstructed pixel field blocks, the apparatus comprising:

an IDCT module arranged to convert the received frame coded DCT coefficient blocks to converted field coded DCT coefficient blocks and to perform an IDCT on the converted field coded DCT coefficient blocks and on the received field coded DCT coefficient blocks in order to produce downconverted pixel field blocks;
and,
a motion compensator arranged to apply motion compensation, as appropriate, to the downconverted pixel field blocks in order to produce the reconstructed pixel field blocks.

An apparatus for downconverting received frame and field coded DCT coefficient blocks to downconverted pixel field blocks, the apparatus comprising:

a first IDCT module arranged to convert the received frame coded DCT coefficient blocks to converted field coded DCT coefficient blocks and to perform a downconverting IDCT on the converted field coded DCT coefficient blocks in order to produce first downconverted pixel field blocks;
and,
a second IDCT module arranged to directly perform a downconverting IDCT on the received field coded DCT coefficient blocks in order to produce second downconverted pixel field blocks.

Dependencies are inferred from the claim text.

Downconverting decoder for interlaced pictures

Life of this patent

Downconverting decoder for interlaced pictures

Life of this patent

Abstract

Claims44