Video encoder, a video decoder and corresponding methods with improved block partitioning

A method for encoding a video bitstream implemented by an encoding device, comprising:

• determining whether first partition constraint information is present in a slice header of the video bitstream;
• encoding the first partition constraint information into the slice header when the first partition constraint information is present in the slice header;
• partitioning a block of the slice into a plurality of sub-blocks according to encoded value of the first partition constraint information;
• encoding an override flag with an overriding value into the video bitstream;
• partitioning the block of the slice into a plurality of sub-blocks according to a default value of the first partition constraint information when the first partition constraint information is not present in the slice header, wherein the default value of the first partition constraint information is a value of second partition constraint information in a sequence parameter set (SPS) of the video bitstream;
• and encoding the override flag with a value different from the overriding value into the video bitstream.

A decoder, comprising:

• one or more processors;
• and
• a non-transitory computer-readable storage medium coupled to the one or more processors and storing programming instructions for execution by the one or more processors, wherein the programming instructions, when executed by the one or more processors, configures the decoder to carry out operations comprising:
• obtaining an override flag from the video bitstream, wherein the override flag indicates whether first partition constraint information is present in a slice header of the video bitstream;
• when a value of the override flag is an overriding value, obtaining first partition constraint information for the slice from the slice header;
• partitioning a block of the slice into a plurality of sub-blocks according to obtained value of the first partition constraint information;
• when the value of the override flag is not the overriding value, partitioning the block of the slice into a plurality of sub-blocks according to a default value of the first partition constraint information, wherein the default value of the first partition constraint information is a value of second partition constraint information from a sequence parameter set (SPS) of the video bitstream;
• and
• reconstructing the block of the slice by reconstructing the plurality of sub-blocks.

An encoder, comprising:

• one or more processors;
• and
• a non-transitory computer-readable storage medium coupled to the one or more processors and storing programming instructions for execution by the one or more processors, wherein the programming instructions, when executed by the one or more processors, configures the encoder to carry out operations comprising:
• determining whether first partition constraint information is present in a slice header of the video bitstream;
• when determining the first partition constraint information is present in the slice header, encoding the first partition constraint information into the slice header;
• partitioning a block of the slice into a plurality of sub-blocks according to encoded value of the first partition constraint information;
• encoding an override flag with an overriding value into the video bitstream;
• when determining the first partition constraint information is not present in the slice header, partitioning the block of the slice into a plurality of sub-blocks according to a default value of the first partition constraint information, wherein the default value of the first partition constraint information is a value of second partition constraint information in a sequence parameter set (SPS) of the video bitstream;
• and
• encoding the override flag with a value different from the overriding value into the video bitstream.