Optimizations on inter-layer prediction signalling for multi-layer video coding

An apparatus for decoding video information, the apparatus comprising:

• a memory configured to store one or more layers of video information, each layer comprising at least one picture;
• and
• a processor operationally coupled to the memory and configured to:
• determine a number of active reference layer pictures associated with at least one of the one or more layers, the number of active reference layer pictures indicating a number of pictures that the at least one picture may utilize for inter-layer prediction;
• determine a number of direct reference layers associated with the at least one picture of the one or more layers, the number of direct reference layers indicating a number of layers that a layer containing the at least one picture may utilize for inter-layer prediction;
• determine that the number of direct reference layers does not equal the number of active reference layer pictures;
• and
• based on the determination that the number of direct reference layers does not equal the number of active reference layer pictures, receive a syntax element that specifies a variable representative of a layer identification of a picture that may be used by the at least one picture of the one or more layers for inter-layer prediction.

A method of encoding video information, the method comprising:

• receiving one or more layers of video information, each layer comprising at least one picture;
• determining a number of active reference layer pictures associated with at least one of the one or more layers, the number of active reference layer pictures indicating a number of pictures that the at least one picture may utilize for inter-layer prediction;
• determining a number of direct reference layers associated with the at least one picture of the one or more layers, the number of direct reference layers indicating a number of layers that a layer containing the at least one picture may utilize for inter-layer prediction;
• determining whether the number of direct reference layers equals the number of active reference layer pictures;
• and
• based on the determination that the number of direct reference layers equals the number of active reference layer pictures, refraining from further signaling inter-layer reference picture information in a video slice associated with the at least one picture of the one or more layers, or
• based on the determination that the number of direct reference layers does not equal the number of active reference layer pictures, signal inter-layer reference picture information in a video slice associated with the at least one picture of the one or more layers.

A method of decoding video information, the method comprising:

• receiving one or more layers of video information, each layer comprising at least one picture;
• determining a number of active reference layer pictures associated with at least one picture of the one or more layers, the number of active reference layer pictures indicating a number of pictures that the at least one picture may utilize for inter-layer prediction;
• determining a number of direct reference layers associated with the at least one picture of the one or more layers, the number of direct reference layers indicating a number of layers that a layer containing the at least one picture may utilize for inter-layer prediction;
• determining that the number of direct reference layers equals the number of active reference layer pictures;
• and
• based on the determination that the number of direct reference layers does not equal the number of active reference layer pictures, receive a syntax element that specifies a variable representative of the nuh layer id of a picture that may be used by the at least one picture of the one or more layers for inter-layer prediction.

A video coding apparatus, comprising:

• means for storing one or more layers of video information, each layer comprising at least one picture;
• means for determining a number of active reference layer pictures associated with at least one picture of the one or more layers, the number of active reference layer pictures indicating a number of pictures that the at least one picture may utilize for inter-layer prediction;
• means for determining a number of direct reference layers associated with the at least one picture of the one or more layers, the number of direct reference layers indicating a number of layers that a layer containing the at least one picture may utilize for inter-layer prediction;
• means for determining that the number of direct reference layers does not equal the number of active reference layer pictures;
• and
• means for receiving a syntax element that specifies a variable representative of a layer identification of a picture that may be used by the at least one picture for inter-layer prediction based on the determination that the number of direct reference layers does not equal the number of active reference layer pictures.

A non-transitory computer readable medium having stored thereon code that when executed causes an apparatus to:

• receive one or more layers of video information, each layer comprising at least one picture;
• determine a number of active reference layer pictures associated with at least one picture of the one or more layers, the number of active reference layer pictures indicating a number of pictures that the at least one picture may utilize for inter-layer prediction;
• determine a number of direct reference layers associated with the at least one picture of the one or more layers, the number of direct reference layers indicating a number of layers that a layer containing the at least one picture may utilize for inter-layer prediction;
• determine that the number of direct reference layers equals the number of active reference layer pictures;
• and
• based on the determination that the number of direct reference layers does not equal the number of active reference layer pictures, receive a syntax element that specifies a variable representative of a layer identification of a picture that may be used by the at least one picture of the one or more layers for inter-layer prediction.