Method for signaling of reference picture resampling with resampling picture size indication in video bitstream

A device for encoding a video bitstream, the device comprising:

• at least one memory configured to store program code;
• and
• at least one processor configured to read the program code and operate as instructed by the program code, the program code including:
• first determining code configured to cause the at least one processor to determine that a conformance window is not used for reference picture resampling;
• second determining code configured to cause the at least one processor to, based on the determining that the conformance window is not used for the reference picture resampling, determine whether a reference picture resampling parameter is to be signaled;
• third determining code configured to cause the at least one processor to, based on determining that the reference picture resampling parameter is to be signaled, determine a plurality of reference region parameters to be used to calculate scaling for the reference picture resampling, the plurality of reference region parameters comprising at least a reference region left offset and a reference region top offset;
• and
• encoding code configured to cause the at least one processor to encode a current picture using the reference picture resampling parameter comprising the plurality of reference region parameters;
• and
• generating code configured to cause the at least one processor to generate an encoded video bitstream based on the encoded current picture, wherein the encoded video bitstream includes a flag indicating that the conformance window is not used for the reference picture resampling and the reference picture resampling parameter.

A non-transitory computer-readable medium storing instructions, the instructions comprising:

• one or more instructions that, when executed by one or more processors of a device for encoding a video bitstream, cause the one or more processors to:
• determine that a conformance window is not used for reference picture resampling;
• based on the determining that the conformance window is not used for the reference picture resampling, determine whether a reference picture resampling parameter is to be signaled;
• based on determining that the reference picture resampling parameter is to be signaled, determine a plurality of reference region parameters to be used to calculate scaling for the reference picture resampling, the plurality of reference region parameters comprising at least a reference region left offset and a reference region top offset;
• and
• encode a current picture using the reference picture resampling parameter comprising the plurality of reference region parameters;
• and
• generate an encoded video bitstream based on the encoded current picture, wherein the encoded video bitstream includes a flag indicating that the conformance window is not used for the reference picture resampling and the reference picture resampling parameter.