Filter positioning and selection

Patent metadata

Field	Value
Publication number	US-9712846-B2
Application number	US-201113640388-A
Country	US
Kind code	B2
Filing date	Apr 11, 2011
Priority date	Apr 12, 2010
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

The present invention relates to a method for encoding and decoding an image signal and to corresponding apparatuses therefor. In particular, during the encoding and/or decoding of an image signal filtering with at least two filters is performed. The sequence of the filter application and possibly the filters are selected and the filtering is applied in the selected filtering order and with the selected filters. The determination of the sequence of applying the filters may be performed either separately in the same way at the encoder and at the decoder, or, it may be determined at the encoder and signaled to the decoder.

First claim

The invention claimed is:

1. An apparatus for decoding an image signal encoded in a bitstream, employing at least two different filters, a first filter and a second filter, to be applied in a filtering process performed when decoding the encoded image signal, the apparatus comprising:
a processor; and
a memory having a program stored thereon, the program causing the processor to execute operations including:
extracting, from the bitstream, an encoding parameter specifying a quantization step size;
determining to perform the filtering process in an order of the first filter followed by the second filter when the quantization step size specified by the encoding parameter is smaller than a threshold, and determining to perform the filtering process in an order of the second filter followed by the first filter when the quantization step size specified by the encoding parameter is larger than the threshold; and
applying the first filter and the second filter according to the determined order when decoding the encoded image signal,

wherein a value of the threshold is dynamically changed based on a size of a motion vector of a block to be decoded.

Assignees

• Narroschke Matthias
• Sasai Hisao
• Sun Patent Trust

Inventors

• Narroschke Matthias
• Sasai Hisao

Classifications

• H04N19/48

  using compressed domain processing techniques other than decoding, e.g. modification of transform coefficients, variable length coding [VLC] data or run-length data (motion estimation in a transform domain H04N19/547; processing of decoded motion vectors H04N19/513) · CPC title

• H04N19/439

  using cascaded computational arrangements for performing a single operation, e.g. filtering · CPC title

• H04N19/136

  Incoming video signal characteristics or properties · CPC title

• H04N19/82

  involving filtering within a prediction loop · CPC title

• H04N19/86 Primary

  involving reduction of coding artifacts, e.g. of blockiness · CPC title