Normative indication of recovery point

A method for encoding a bitstream, the method comprising:

• determining that a particular picture in a coded video sequence (CVS) of pictures in the bitstream is to be a start of a recovery point period, wherein a last coded picture in decoding order in the recovery point period is to be a recovery point picture;
• defining the particular picture as a gradual decoding refresh (GDR) picture such that the CVS begins with the GDR picture and includes the recovery point picture;
• and
• encoding in the CVS a normative indication of the recovery point period in the bitstream, wherein
• the normative indication of the recovery point period comprises information indicating that the recovery point period starts with the GDR picture, and
• an indication of the start of the recovery point period is encoded in a network abstraction layer (NAL) unit having a type of picture header and/or an indication of the end of the recovery point period is encoded in the NAL unit.

A decoding apparatus for decoding a video bitstream comprising a coded video sequence (CVS) of pictures beginning with a gradual decoding refresh (GDR) picture and including a recovery point picture, wherein the GDR picture starts a recovery point period and the recovery point picture ends the recovery point period, the decoding apparatus comprising:

• memory;
• and
• processing circuitry, wherein the decoding apparatus is configured to perform a process that comprises:
• obtaining the video bitstream, wherein the video bitstream comprises a coded video sequence (CVS) of pictures, the CVS of pictures beginning with a gradual decoding refresh (GDR) picture and including a recovery point picture, wherein the GDR picture starts a recovery point period and the recovery point picture ends the recovery point period;
• decoding from the CVS a normative indication of the recovery point period;
• and
• decoding from a network abstraction layer (NAL) unit having a type of picture header an indication of the start of the recovery point period and/or an indication of the end of the recovery point period, wherein
• the normative indication of the recovery point period indicates that the GDR picture starts the recovery point period.

An encoding apparatus for encoding a bitstream, the encoding apparatus comprising:

• memory;
• and
• processing circuitry, wherein the encoding apparatus is configured to:
• determine that a particular picture in a coded video sequence (CVS) of pictures in the bitstream is to be a start of a recovery point period, wherein a last coded picture in decoding order in the recovery point period is to be a recovery point picture;
• defining the particular picture as a gradual decoding refresh (GDR) picture such that the CVS begins with the GDR picture and includes the recovery point picture;
• determining the recovery point picture;
• and
• encoding in the CVS a normative indication of the recovery point period in the bitstream, wherein
• the normative indication of the recovery point period comprises information indicating that the recovery point period starts with the GDR picture, and
• an indication of the start of the recovery point period is encoded in a network abstraction layer (NAL) unit having a type of picture header and/or an indication of the end of the recovery point period is encoded in the NAL unit.