Extending search range for reference blocks beyond current ctu

A video encoding apparatus for video encoding, comprising:

• processing circuitry configured to:
• determine a first area in a coding tree unit (CTU) of a current block of a picture that is collocated with a second area in a different CTU of the picture, the first area and the second area having a same position in the CTU of the current block and the different CTU,
• determine, based on a decoding status of the first area at a time point when the current block is to be decoded, whether one or more reference blocks of the second area are available for encoding the current block, and
• in response to a determination that the one or more reference blocks of the second area are available, encode the current block based on one or more reference blocks of the second area.

A non-transitory computer readable medium having instructions stored therein, which when executed by a processor in a video encoder causes the processor to execute a method comprising:

• (i) determining a first area in a coding tree unit (CTU) of a current block of a picture that is collocated with a second area in a different CTU of the picture, the first area and the second area having a same position in the CTU of the current block and the different CTU;
• determining, based on a decoding status of the first area at a time point when the current block is to be decoded, whether one or more reference blocks of the second area are available for encoding the current block;
• and
• (iii) in response to a determination that the one or more reference blocks of the second area are available, encoding the current block based on one or more reference blocks of the second area.