Arithmetic encoders, arithmetic decoders, video encoder, video decoder, methods for encoding, methods for decoding and computer program

Patent metadata

Field	Value
Publication number	US-11431352-B2
Application number	US-202117142071-A
Country	US
Kind code	B2
Filing date	Jan 5, 2021
Priority date	Jul 6, 2018
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

An arithmetic encoder for encoding a plurality of symbols having symbol values is configured to derive an interval size information for an arithmetic encoding of one or more symbol values to be encoded based on a plurality of state variable values representing statistics of a plurality of previously encoded symbol values with different adaptation time constants. The arithmetic encoder is configured to map a first state variable value, or a scaled and/or rounded version thereof, using a lookup-table and to map a second state variable value, or a scaled and/or rounded version thereof using the lookup-table, in order to obtain the interval size information describing an interval size for the arithmetic encoding of one or more symbols to be encoded. Further arithmetic encoders, arithmetic decoders, video encoders, video decoder, methods for encoding, methods for decoding and computer programs are also disclosed which are based on the same concept and on other concepts.

First claim

The invention claimed is:

1. An arithmetic encoder for encoding a plurality of symbols comprising symbol values,
wherein the arithmetic encoder is configured to derive an interval size information for an arithmetic encoding of one or more symbol values to be encoded on the basis of a plurality of state variable values, which represent statistics of a plurality of previously encoded symbol values with different adaptation time constants,
wherein the arithmetic encoder is configured to derive a combined state variable value one the basis of the plurality of state variable values, and
wherein the arithmetic encoder is configured to map the combined state variable value, or a scaled and/or rounded version thereof using a look-up table, in order to acquire the interval size information describing an interval size for the arithmetic encoding of one or more symbols to be encoded.

2. The arithmetic encoder according to claim 1 ,
wherein the arithmetic encoder is configured to determine a subinterval width R·p k according to

R
·

p
k

=

{

LUT
⁢

⁢

3
⁡

[

⌊

s
k

·

a
k

⌋

]

⁢

[

Qr
⁡

(
R
)

]

,

if
⁢

⁢

s
k

≥
0.

R
-

LUT
⁢

⁢

3
⁡

[

⌊

-

s
k

·

a
k

⌋

]

⁢

[

Qr
⁡

(
R
)

]

,

else

.

wherein LUT3 is a 2D lookup-table;
wherein └·┘ is a floor operator;
wherein s k is a combined state value;
wherein a k is a weighting value associated with the combined state variable value;
wherein R is an interval size; and
wherein Qr(R) is a quantized value of the interval size.

3. The arithmetic encoder according to claim 1 ,
wherein the arithmetic encoder is configured to determine one or more updated state variable values s i k according to

s
i
k

=

{

s
i
k

+

⌊

A
⁡

[

z
+

⌊

⁢

Assignees

• Fraunhofer Ges Forschung

Inventors

• Kirchhoffer Heiner
• Stegemann Jan
• Marpe Detlev
• Haase Paul
• Matlage Stefan
• Bartnik Christian
• Schwarz Heiko
• Wiegand Thomas

Classifications

• H04N19/13

  Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC] · CPC title

• H03M7/42

  using table look-up for the coding or decoding process, e.g. using read-only memory {(H03M7/4006 takes precedence)} · CPC title

• H03M7/4006 Primary

  Conversion to or from arithmetic code · CPC title

• H03M7/02

  Conversion to or from weighted codes, i.e. the weight given to a digit depending on the position of the digit within the block or code word · CPC title

• H03M7/3082

  Vector coding (for television signals, see H04N19/94) · CPC title