Method and arrangement for coding transform coefficients in picture and/or video coders and decoders and a corresponding computer program and a corresponding computer-readable storage medium

Patent metadata

Field	Value
Publication number	US-9490838-B2
Application number	US-42815709-A
Country	US
Kind code	B2
Filing date	Apr 22, 2009
Priority date	May 2, 2002
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

The present invention describes a method and an arrangement for coding transform coefficients in picture and/or video coders and decoders and a corresponding computer program and a corresponding computer-readable storage medium, which can particularly be employed as a novel efficient method for binary-arithmetic coding transform coefficients in the field of video coding.
For this, it is suggested that, for blocks of (video) pictures containing significant transform coefficients, coding of the transform coefficients takes place in such a way that, for each block in a scan process, the positions of significant transform coefficients in the block and subsequently, in a reverse scan order—starting from the last significant transform coefficient within the block—the values (levels) of the significant transform coefficients are determined and coded.

First claim

The invention claimed is:

1. A method, performed on a processor, for coding transform coefficients
wherein
for blocks of (video) pictures containing transform coefficients being unequal to zero, a coding of transform coefficients takes place in such a way that, for each block,
a significance map is coded, the significance map specifying the positions of transform coefficients being unequal to zero in the block in a scan order, and subsequently,
the values (levels) of the transform coefficients being unequal to zero are coded by, in a reverse scan order—starting with the last transform coefficient being unequal to zero within the block—binary entropy coding bins of a binarization of a magnitude of the transform coefficients being unequal to zero in a context-dependent way using contexts depending on how many transform coefficients having a magnitude of greater than 1 have already been coded in the reverse scan order up to a respective currently coded transform coefficient with coding all bins of the binarization of the respective currently to be coded transform coefficient being unequal to zero before proceeding with coding the bins of the binarization of a—in the reverse scan order—succeeding transform coefficient being unequal to zero.

2. The method according to claim 1 , wherein when coding the significance map, each transform coefficient being unequal to zero in the scan order is characterized by a first one-bit symbol (SIG) serving to characterize transform coefficients being unequal to zero, i. e. each transform coefficient being unequal to zero including the last transform coefficient being unequal to zero in the scan order if it is different from the last transform coefficient of the block in the scan order, or excluding the last transform coefficient being unequal to zero in the scan order if it is the last transform coefficient of the block in the scan order, and the last transform coefficient being unequal to zero is characterized by a second one-bit symbol (LAST) indicating that the respective transform coefficient being unequal to zero is the last transform coefficient being unequal to zero in the scan order if it is different from the last transform coefficient of the block in the scan order.

3. The method according to claim 1 , wherein for each transform coefficient being unequal to zero, the sign is indicated by a one-bit symbol (SIGN) and the magnitude is indicated by a binary-coded symbol (ABS).

4. The method according to claim 1 , wherein the magnitude is indicated by a symbol (ABS) in unary binarization or by a symbol (ABS) having a prefix part and a suffix part, wherein the prefix part consists of ones and the suffix part is coded in a 0th order exp-golomb code.

5. The method according to claim 1 , wherein block types of transform coefficients having comparable statistics are summarized to block categories.

6. The method according to claim 1 , wherein blocks containing transform coefficients being unequal to zero are characterized by a one-bit symbol (CBP4) in connection with further syntax elements, including (CBP) or macro block mode.

7. The method according to claim 6 , wherein modeling
for the one-bit symbol (CBP4),
for coding the significance map and/or
for coding the coefficient magnitudes

takes place in a context-dependent way.

8. The method according to claim 1 , wherein by transferring a one-bit symbol (SIG) for each coefficient of a block and a one-bit symbol (LAST) for each transform coefficient being unequal to zero of a block, the significance map is coded, wherein the transfer takes place in the scan order, (SIG) serves for identifying transform coefficients being unequal to zero and (LAST) indicates whether there are further transform coefficients being unequal to zero in the block.

9. The method according to claim 8 , wherein no significance information (SIG, LAST) is transferred for the last scan position of a block.

10. An arrangement having at least one processor and/or chip formed such that a method for coding transform coefficients can be performed, wherein
for blocks of (video) pictures containing transform coefficients being unequal to zero, a coding of transform coefficients takes place in such a way that, for each block,
a significance map is coded, the significance map specifying the positions of transform coefficients being unequal to zero in the block in a scan order, and subsequently,
the values (levels) of the transform coefficients being unequal to zero are coded by, in a reverse scan order—starting with the last transform coefficient being unequal to zero within the block—binary entropy coding bins of a binarization of a magnitude of the transform coefficients being unequal to zero in a context-dependent way using contexts depending on how many transform coefficients having a magnitude of greater than 1 have already been coded in the reverse scan order up to a respective currently coded transform coefficient with coding all bins of the binarization of the respective currently to be coded transform coefficient being unequal to zero before proceeding with coding the bins of the binarization of a—in the reverse scan order—succeeding transform coefficient being unequal to zero.

11. A non-transitory computer-readable storage medium on which a program is stored, enabling a computer, after having been loaded into the memory of the computer, to perform a method for coding transform coefficients, wherein
for blocks of (video) pictures containing transform coefficients being unequal to zero, a coding of transform coefficients takes place in such a way that, for each block,
a significance map is coded, the significance map specifying the positions of transform coefficients being unequal to zero in the block in a scan order, and subsequently,
the values (levels) of the transform coefficients being unequal to zero are coded by, in a reverse scan order—starting with the last transform coefficient being unequal to zero within the block—binary entropy coding bins of a binarization of a magnitude of the transform coefficients being unequal to zero in a context-dependent way using contexts depending on how many transform coefficients having a magnitude of greater than 1 have already been coded in the reverse scan order up to a respective currently coded transform coefficient, with coding all bins of the binarization of the respective currently to be coded transform coefficient being unequal to zero before proceeding with coding the bins of the binarization of a—in the reverse scan order—succeeding transform coefficient being unequal to zero.

12. A method, performed on a processor, for decoding a coding of a significance map and a subsequent coding of values of transform coefficients being unequal to zero for blocks of (video) pictures containing transform coefficients being unequal to zero, the significance map specifying the positions of the transform coefficients being unequal to zero in a scan order, and the coding of values of transform coefficients being unequal to zero comprising coded values of the transform coefficients being unequal to zero in a reverse scan order—starting with the last transform coefficient being unequal to zero, comprising the steps of:
decoding the significance mapping in the scan order; and
decoding the coded values of transform coefficients being unequal to zero by, in the reverse scan order, binary entropy decoding bins of a binarization of a magnitude of the transform coefficients being unequal to zero in a context-dependent way using contexts depending on how many transform coefficients having a magnitude of greater than 1 have already been decoded in the reverse scan order up to a respective currentl

Assignees

• Schwarz Heiko
• Marpe Detlef
• Wiegand Thomas
• Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E V

Inventors

• Schwarz Heiko
• Marpe Detlef
• Wiegand Thomas

Classifications

• H04N19/136

  Incoming video signal characteristics or properties · CPC title

• H03M7/4006 Primary

  Conversion to or from arithmetic code · CPC title

• H04N19/91

  Entropy coding, e.g. variable length coding [VLC] or arithmetic coding · CPC title

• H04N19/93

  Run-length coding · CPC title

• H04N19/60

  using transform coding · CPC title