Method and an apparatus for processing a video signal

A method for decoding a bitstream by a video decoding apparatus, the method comprising:

• obtaining, by the video decoding apparatus from the bitstream, first information for a current block, the first information specifying whether the bitstream contains transform coefficient information for the current block;
• obtaining, by the video decoding apparatus from the bitstream, second information for a sub-block of the current block based on the first information having a first value, the second information of the sub-block specifying whether the bitstream contains transform coefficient information for the sub-block;
• obtaining, by the video decoding apparatus from the bitstream, the transform coefficient information for the sub-block based on the second information of the sub-block having the first value;
• obtaining, by the video decoding apparatus, residual data of the sub-block based on the obtained transform coefficient information;
• and
• reconstructing, by the video decoding apparatus, the sub-block based on the obtained residual data.

A video decoding apparatus configured to decode a bitstream, the video decoding apparatus comprising:

• an entropy decoding unit configured to:
• obtain, from the bitstream, first information for a current block, the first information specifying whether the bitstream contains transform coefficient information for the current block,
• obtain, from the bitstream, second information for a sub-block of the current block based on the first information having a first value, the second information of the sub-block specifying whether the bitstream contains transform coefficient information for the sub-block, and
• obtain, from the bitstream, the transform coefficient information for the sub-block based on the second information of the sub-block having the first value;
• and
• an inverse-transform unit configured to:
• obtain residual data of the sub-block based on the obtained transform coefficient information, and
• reconstruct the sub-block based on the obtained residual data.

A method for encoding a bitstream by a video encoding apparatus, the method comprising:

• encoding, by the video encoding apparatus into the bitstream, first information for a current block, the first information specifying whether the bitstream contains transform coefficient information for the current block;
• encoding, by the video encoding apparatus into the bitstream, second information for a sub-block of the current block based on the first information having a first value, the second information of the sub-block specifying whether the bitstream contains transform coefficient information for the sub-block;
• encoding, by the video encoding apparatus into the bitstream, the transform coefficient information for the sub-block based on the second information of the sub-block having the first value;
• obtaining, by the video encoding apparatus, residual data of the sub-block based on the encoded transform coefficient information;
• and
• reconstructing, by the video encoding apparatus, the sub-block based on the obtained residual data.

A video encoding apparatus configured to encode a bitstream, the video encoding apparatus comprising:

• an entropy coding unit configured to:
• encode, into the bitstream, first information for a current block, the first information specifying whether the bitstream contains transform coefficient information for the current block,
• encode, into the bitstream, second information for a sub-block of the current block based on the first information having a first value, the second information of the sub-block specifying whether the bitstream contains transform coefficient information for the sub-block, and
• encode, into the bitstream, the transform coefficient information for the sub-block based on the second information of the sub-block having the first value;
• and
• an inverse-transform unit configured to:
• obtain residual data of the sub-block based on the encoded transform coefficient information, and
• reconstruct the sub-block based on the obtained residual data.