Method and apparatus for deriving motion vectors of macroblocks from motion vectors of pictures of base layer when encoding/decoding video signal

A method for encoding an input video signal, the method comprising:

• encoding the video signal in a first scheme and outputting a bitstream of a first layer;
• and
• encoding the video signal in a second scheme and outputting a bitstream of a second layer including frames having a smaller screen size than frames in the bitstream of the first layer,
• the encoding in the first scheme including a process for recording, in the bitstream of the first layer, information allowing a derivative vector, obtained based on a scaled vector obtained by multiplying a motion vector of a first block present in the bitstream of the second layer by a derivation factor and scaling the multiplied motion vector by the ratio of a frame size of the first layer to a frame size of the second layer, to be used as a motion vector of an image block in an arbitrary frame present in the video signal and not temporally coincident with a frame including the first block.

An apparatus for receiving and decoding a bitstream of a first layer including frames, each including pixels having difference values, into a video signal, the apparatus comprising:

• a first decoder for decoding the bitstream of the first layer in a first scheme into video frames having original images;
• and
• a second decoder for receiving a bitstream of a second layer including frames having a smaller screen size than the video frames, extracting encoding information including motion vector information from the received bitstream of the second layer, and providing the encoding information to the first decoder,
• the first decoder including means for obtaining a motion vector of a target block in an arbitrary frame present in the bitstream of the first layer using a derivative vector obtained based on a scaled vector obtained by multiplying a motion vector of a first block in a frame not temporally coincident with the arbitrary frame by a derivation factor and scaling the multiplied motion vector by the ratio of a frame size of the first layer to a frame size of the second layer, the motion vector of the first block being included in the encoding information.

An apparatus for encoding an input video signal, the apparatus comprising:

• a first encoder for encoding the video signal in a first scheme and outputting a bitstream of a first layer;
• and
• a second encoder for encoding the video signal in a second scheme and outputting a bitstream of a second layer including frames having a smaller screen size than frames in the bitstream of the first layer,
• the first encoder including means for recording, in the bitstream of the first layer, information allowing a derivative vector, obtained based on a resulting vector of multiplication of a motion vector of a first block present in the bitstream of the second layer by a derivation factor, to be used as a motion vector of an image block in an arbitrary frame present in the video signal and not temporally coincident with a frame including the first block,
• the derivation factor being equal to the product of a first factor corresponding to the ratio of a frame size of the first layer to a frame size of the second layer and a second factor corresponding to the ratio of a time interval between the arbitrary frame and a frame, present downstream of the arbitrary frame in a target derivative vector direction of the image block, to a time interval between the frame including the first block and another frame including a block indicated by the motion vector of the first block.

A method for encoding an input video signal, the method comprising:

• encoding the video signal in a first scheme and outputting a bitstream of a first layer;
• and
• encoding the video signal in a second scheme and outputting a bitstream of a second layer including frames having a smaller screen size than frames in the bitstream of the first layer,
• the encoding in the first scheme including:
• a first process for obtaining a derivation factor by multiplying a first factor corresponding to the ratio of a frame size of the first layer to a frame size of the second layer by a second factor corresponding to the ratio of a time interval between an arbitrary frame, present in the video signal and not temporally coincident with a frame including a first block present in the bitstream of the second layer, and a frame, present downstream of the arbitrary frame in a target derivative vector direction of an image block present in the arbitrary frame, to a time interval between the frame including the first block and another frame including a block indicated by the motion vector of the first block;
• and
• a second process for recording, in the bitstream of the first layer, information allowing a derivative vector, obtained based on a resulting vector of multiplication of the motion vector of the first block by the derivation factor, to be used as a motion vector of the image block present in the arbitrary frame.

An apparatus for receiving and decoding a bitstream of a first layer including frames, each including pixels having difference values, into a video signal, the apparatus comprising:

• a first decoder for decoding the bitstream of the first layer in a first scheme into video frames having original images;
• and
• a second decoder for receiving a bitstream of a second layer including frames having a smaller screen size than the video frames, extracting encoding information including motion vector information from the received bitstream of the second layer, and providing the encoding information to the first decoder,
• the first decoder including means for obtaining a motion vector of a target block in an arbitrary frame present in the bitstream of the first layer using a derivative vector obtained based on a resulting vector of multiplication of a motion vector of a first block in a frame not temporally coincident with the arbitrary frame by a derivation factor, the motion vector of the first block being included in the encoding information,
• the derivation factor being equal to the product of a first factor corresponding to the ratio of a frame size of the first layer to a frame size of the second layer and a second factor corresponding to the ratio of a time interval between the arbitrary frame and a frame, present downstream of the arbitrary frame in a target derivative vector direction of the target block, to a time interval between the frame including the first block and another frame including a block indicated by the motion vector of the first block.

A method for receiving and decoding a bitstream of a first layer including frames, each including pixels having difference values, into a video signal, the method comprising:

• decoding the bitstream of the first layer into video frames having original images according to a scalable scheme using encoding information including motion vector information, the encoding information being extracted and provided from an input bitstream of a second layer including frames having a smaller screen size than frames in the first layer,
• decoding the bitstream of the first layer into the video frames including:
• a first process for obtaining a derivation factor of a target block in an arbitrary frame present in the bitstream of the first layer;
• and
• a second process for obtaining a motion vector of the target block using a derivative vector obtained based on a resulting vector of multiplication of a motion vector of a first block in a frame not temporally coincident with the arbitrary frame by the derivation factor, the motion vector of the first block being included in the encoding information,
• the derivation factor being obtained based on the product of a first factor corresponding to the ratio of a frame size of the first layer to a frame size of the second layer and a second factor corresponding to the ratio of a time interval between the arbitrary frame and a frame, present downstream of the arbitrary frame in a target derivative vector direction of the target block, to a time interval between the frame including the first block and another frame including a block indicated by the motion vector of the first block.