Context initialization based on slice header flag and slice type

Patent metadata

Field	Value
Publication number	US-10531091-B2
Application number	US-201816227322-A
Country	US
Kind code	B2
Filing date	Dec 20, 2018
Priority date	Jun 30, 2011
Publication date	Jan 7, 2020
Grant date	Jan 7, 2020

Abstract

Technique for initialization of encoders and decoders. In some cases, the decoder receives a slice and identifies if the slice is either a forward predicted B-slice or a backward predicted B-slice, and not both a forward and backward predicted B-slice, and based upon this identification initializes, using a P-slice technique, a context associated with the slice.

First claim

We claim:

1. A method for decoding a video frame, the method comprising:
receiving a bitstream of encoded video data;
decoding, from the bitstream, a syntax element indicative of a slice type of a slice;
when the slice type indicates a B slice type or a P slice type, decoding, from the bitstream, a flag that is used to determine a Context-Adaptive Binary Arithmetic Coding (CABAC) context initialization method for the B slice type or the P slice type; and
initializing a CABAC context associated with the slice type, wherein
in a case that the slice type indicates the B slice type and a value of the flag is equal to a first value, a CABAC context associated with the B slice type is initialized by a first initialization method,
in a case that the slice type indicates the B slice type and the value of the flag is equal to a second value, a CABAC context associated with the B slice type is initialized by a second initialization method,
in a case that the slice type indicates the P slice type and the value of the flag is equal to the first value, a CABAC context associated with the P slice type is initialized by the second initialization method, and
in a case that the slice type indicates an I slice type, a CABAC context associated with the I slice type is initialized by a third initialization method.

2. The method of claim 1 , further comprising:
decoding the video frame; and
displaying the decoded video frame.

3. The method of claim 1 , further comprising:
decoding the bitstream of encoded video data; and
displaying the decoded video data.

4. An apparatus for decoding a video frame, the apparatus comprising a processor and memory, the processor, working together with the memory, being configured to:
receive a bitstream of encoded video data;
decode, from the bitstream, a syntax element indicative of a slice type of a slice;
when the slice type indicates a B slice type or a P slice type, decode, from the bitstream, a flag that is used to determine a Context-Adaptive Binary Arithmetic Coding (CABAC) context initialization method for the B slice type or the P slice type; and
initialize a CABAC context associated with the slice type, wherein
in a case that the slice type indicates the B slice type and a value of the flag is equal to a first value, a CABAC context associated with the B slice type is initialized by a first initialization method,
in a case that the slice type indicates the B slice type and the value of the flag is equal to a second value, a CABAC context associated with the B slice type is initialized by a second initialization method,
in a case that the slice type indicates the P slice type and the value of the flag is equal to the first value, a CABAC context associated with the P slice type is initialized by the second initialization method, and
in a case that the slice type indicates an I slice type, a CABAC context associated with the I slice type is initialized by a third initialization method.

5. The apparatus of claim 4 , wherein the processor, working together with the memory, is further configured to:
decode the video frame; and
display the decoded video frame.

6. The apparatus of claim 4 , wherein the processor, working together with the memory, is further configured to:
decode the bitstream of encoded video data; and
display the decoded video data.

Assignees

• Velos Media Llc

Inventors

• Misra Kiran
• Segall Christopher

Classifications

• H04N19/159

  Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction · CPC title

• H04N19/436

  using parallelised computational arrangements · CPC title

• H04N19/46

  Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) · CPC title

• H04N19/13 Primary

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

• H04N19/174

  the region being a slice, e.g. a line of blocks or a group of blocks · CPC title