Method and apparatus for coded block flag coding in high efficiency video coding

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

• receiving the video bitstream from a media or a processor;
• decoding a cbf (coded block flag) associated with a TU (transform unit), wherein the cbf is recovered from the video bitstream;
• and
• determining RQT (residual quad-tree structure) of the TU based on the cbf, wherein signaling of the cbf is the same for a luma component and a chroma component.

A method for coding a cbf (coded block flag), the method comprising:

• determining residues of a current CU (coding unit) of a color component;
• determining a first cbf (coded block flag) of the color component indicating whether the current CU of the color component has at least one non-zero transform coefficient;
• if the current CU has at least one non-zero transform coefficient, determining four second cbfs of the color component, each indicating whether one of four sub-blocks in the current CU of the color component has at least one non-zero transform coefficient;
• and
• incorporating the first cbf of the color component into a video bitstream, or both the first cbf and the second cbfs of the color component into the video bitstream if the second cbfs exist;
• and
• wherein the current CU of the color component has a size greater than a maximum TU size of the color component.

A method for coding a cbf (coded block flag), the method comprising:

• receiving a TU (transform unit) from a media or a processor;
• determining RQT (residual quad-tree) associated with the TU;
• and
• determining one or more cbfs corresponding to the RQT of the TU, wherein signaling of the cbf is the same for a luma component and a chroma component.

An apparatus for decoding a video bitstream, the apparatus comprising:

• means for receiving the video bitstream from a media;
• means for decoding a first cbf (coded block flag) of a color component indicating whether a current CU (coding unit) of the color component has at least one non-zero transform coefficient, wherein the first cbf of the color component is recovered from the video bitstream;
• means for decoding a second cbf of the color component, each second cbf indicating whether one of four sub-blocks in the current CU of the color component has at least one non-zero transform coefficient, according to decoding result of the first cbf of the color component, wherein the second cbf of the color component is recovered from the video bitstream;
• and
• means for determining residual quad-tree structure of the current CU of the color component based on the first cbf of the color component, or based on the first cbf and the second cbfs of the color component if the second cbfs exist;
• and
• wherein the current CU of the color component has a size greater than a maximum TU size of the color component.

An apparatus for coding a cbf (coded block flag), the apparatus comprising:

• means for receiving a current CU (coding unit) of a color component from a media or a processor;
• means for determining a first cbf (coded block flag) of the color component indicating whether the current CU has at least one non-zero transform coefficient;
• means for determining four second cbfs of the color component, each indicating whether one of four sub-blocks in the current CU of the color component has at least one non-zero transform coefficient, if the current CU of the color component has at least one non-zero transform coefficient;
• and
• means for incorporating the first cbf of the color component into a video bitstream, or both the first cbf and the second cbfs of the color component into the video bitstream if the second cbfs exist;
• and
• wherein the current CU of the color component has a size greater than a maximum TU size of the color component.