Gradual Decoding Refresh In Video Coding

A method of encoding a coded video bitstream comprising:

• determining a value of a variable no incorrect picture output flag (NoIncorrectPicOutputFlag), wherein the variable NoIncorrectPicOutputFlag is equal to one when an associated intra random access point (IRAP) access unit or a gradual decoding refresh (GDR) access unit is a first access unit in a coded video bitstream in decoding order or the associated IRAP access unit or the GDR access unit is a first access unit that follows an end of sequence network abstraction layer (NAL) unit in decoding order;
• determining a value of a GDR enabled flag (gdr_enabled_flag), wherein the gdr_enabled_flag is signaled in a sequence level parameter set (SPS) in the coded video bitstream, and the flag gdr_enabled_flag is equal to one specifying that a GDR picture may be present in a coded video sequence (CVS);
• setting a picture output flag (PictureOutputFlag) to zero to prevent a picture from being output when a gdr_enabled_flag associated with the CVS containing a coded current picture is equal to one and the coded current picture is a coded GDR picture contained in an access unit with a variable NoIncorrectPicOutputFlag equal to one;
• and
• encoding the coded video bitstream based on the NoIncorrectPicOutputFlag, the gdr_enabled_flag, and the PictureOutputFlag.

A non-transitory computer readable medium comprising a computer program product for use by a decoding device, the computer program product comprising computer executable instructions stored on the non-transitory computer readable medium such that when executed by a processor cause the decoding device to:

• determine a value of a variable no incorrect picture output flag (NoIncorrectPicOutputFlag), wherein the variable NoIncorrectPicOutputFlag is equal to one when an associated intra random access point (IRAP) access unit or a gradual decoding refresh (GDR) access unit is a first access unit in the coded video bitstream in decoding order or the associated IRAP access unit or the GDR access unit is a first access unit that follows an end of sequence network abstraction layer (NAL) unit in decoding order;
• determine a value of a GDR enabled flag (gdr_enabled_flag), wherein the gdr_enabled_flag is signaled in a sequence level parameter set (SPS) in the coded video bitstream, and the flag gdr_enabled_flag is equal to one specifying that a GDR picture may be present in a coded video sequence (CVS);
• set a picture output flag (PictureOutputFlag) to zero to prevent a picture from being output when a gdr_enabled_flag associated with the CVS containing a coded current picture is equal to one and the coded current picture is a coded GDR picture contained in an access unit with a variable NoIncorrectPicOutputFlag equal to one;
• and
• decode NAL units of the coded GDR picture.