Bitstream constraints and motion vector restriction for inter-view or inter-layer reference pictures

A method of inter-view or inter-layer video encoding, the method comprising:

• determining information, which is used for deriving a motion vector for a current block from a motion vector predictor, that ensures that the derived motion vector is compliant with a motion vector restriction, wherein the motion vector refers to an inter-view or an inter-layer reference picture, and wherein the motion vector restriction restricts a range of the motion vector to refer to a sub-portion of the inter-view or inter-layer reference picture;
• deriving the motion vector for the current block based on the information;
• inter-view or inter-layer prediction encoding the current block based on the derived motion vector;
• and
• generating for output the determined information for deriving the motion vector.

A device comprising a video decoder, the video decoder comprising one or more processors and configured to:

• receive a bitstream that includes information for deriving a motion vector for a current block from a motion vector predictor, wherein the motion vector refers to an inter-view or an inter-layer reference picture, wherein the bitstream is constrained such that the information ensures that the derived motion vector is compliant with a motion vector restriction, and wherein the motion vector restriction restricts a range of the motion vector to refer to a sub-portion of the inter-view or inter-layer reference picture;
• derive the motion vector for the current block based on the information in the bitstream;
• and
• inter-view or inter-layer prediction decode the current block based on the derived motion vector.

A device comprising a video encoder, the video encoder comprising one or more processors and configured to:

• determine information, which is used for deriving a motion vector for a current block from a motion vector predictor, that ensures that the derived motion vector is compliant with a motion vector restriction, wherein the motion vector refers to an inter-view or an inter-layer reference picture, and wherein the motion vector restriction restricts a range of the motion vector to refer to a sub-portion of the inter-view or inter-layer reference picture;
• derive the motion vector for the current block based on the information;
• inter-view or inter-layer prediction encode the current block based on the derived motion vector;
• and
• generate for output the determined information for deriving the motion vector.

A computer-readable storage medium having stored thereon instructions that when executed cause one or more processors of a device for decoding video data to:

• receive a bitstream that includes information for deriving a motion vector for a current block from a motion vector predictor, wherein the motion vector refers to an inter-view or an inter-layer reference picture, wherein the bitstream is constrained such that the information ensures that the derived motion vector is compliant with a motion vector restriction, and wherein the motion vector restriction restricts a range of the motion vector to refer to a sub-portion of the inter-view or inter-layer reference picture;
• derive the motion vector for the current block based on the information in the bitstream;
• and
• inter-view or inter-layer prediction decode the current block based on the derived motion vector.

A device comprising:

• means for receiving a bitstream that includes information for deriving a motion vector for a current block from a motion vector predictor, wherein the motion vector refers to an inter-view or an inter-layer reference picture, wherein the bitstream is constrained such that the information ensures that the derived motion vector is compliant with a motion vector restriction, and wherein the motion vector restriction restricts a range of the motion vector to refer to a sub-portion of the inter-view or inter-layer reference picture;
• means for deriving the motion vector for the current block based on the information in the bitstream;
• and
• means for inter-view or inter-layer prediction decoding the current block based on the derived motion vector.