Constraints on picture output ordering in a video bitstream

An apparatus for processing video data comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to:

• perform a conversion between a video comprising one or more pictures and a bitstream of the video according to a first rule,
• wherein the first rule specifies that the bitstream comprises at least a first picture that is output,
• wherein the first picture is in an output layer,
• wherein the first picture comprises a syntax element equal to one,
• wherein the syntax element affects a decoded picture output and a removal process associated with a hypothetical reference decoder (HRD),
• wherein the bitstream comprises multiple layers in multiple access units (AUs) comprising one or more pictures according to a third format rule,
• wherein the third format rule specifies that, responsive to an end of sequence (EOS) network abstraction layer (NAL) unit for a first layer being present in a first AU in the bitstream, a subsequent picture of each of one or more higher layers of the first layer in an AU following the first AU in the bitstream is a coded layer video sequence start (CLVSS) picture, and
• wherein the third format rule further specifies that a second picture in a decoding order for a second layer, which is present in a coded video sequence (CVS) that includes the first layer, that uses the first layer as a reference layer is a CLVSS picture.

A non-transitory computer-readable storage medium storing instructions that cause a processor to:

• perform a conversion between a video comprising one or more pictures and a bitstream of the video according to a first rule,
• wherein the first rule specifies that the bitstream comprises at least a first picture that is output,
• wherein the first picture is in an output layer,
• wherein the first picture comprises a syntax element equal to one,
• wherein the syntax element affects a decoded picture output and a removal process associated with a hypothetical reference decoder (HRD),
• wherein the bitstream comprises multiple layers in multiple access units (AUs) comprising one or more pictures according to a third format rule,
• wherein the third format rule specifies that, responsive to an end of sequence (EOS) network abstraction layer (NAL) unit for a first layer being present in a first AU in the bitstream, a subsequent picture of each of one or more higher layers of the first layer in an AU following the first AU in the bitstream is a coded layer video sequence start (CLVSS) picture, and
• wherein the third format rule further specifies that a second picture in a decoding order for a second layer, which is present in a coded video sequence (CVS) that includes the first layer, that uses the first layer as a reference layer is a CLVSS picture.

A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises:

• generating a bitstream of the video according to a first rule,
• wherein the first rule specifies that the bitstream comprises at least a first picture that is output,
• wherein the first picture is in an output layer,
• wherein the first picture comprises a syntax element equal to one,
• wherein the syntax element affects a decoded picture output and a removal process associated with a hypothetical reference decoder (HRD),
• wherein the bitstream comprises multiple layers in multiple access units (AUs) comprising one or more pictures according to a third format rule,
• wherein the third format rule specifies that, responsive to an end of sequence (EOS) network abstraction layer (NAL) unit for a first layer being present in a first AU in the bitstream, a subsequent picture of each of one or more higher layers of the first layer in an AU following the first AU in the bitstream is a coded layer video sequence start (CLVSS) picture, and
• wherein the third format rule further specifies that a second picture in a decoding order for a second layer, which is present in a coded video sequence (CVS) that includes the first layer, that uses the first layer as a reference layer is a CLVSS picture.