As schemes that encode 3D video images, various schemes are proposed. In this case, the 3D video image is a video image generated by a video signal configured by a video signal of a first view point (to be referred to as a first-view-point video signal hereinafter) and a video signal of the second view point (to be referred to as a second-view-point video signal hereinafter). One of the first-view-point video signal and the second-view-point video signal is a video signal for a right eye, and the other is a video signal for a left eye. A video signal configured by only a video signal of a first view point is called a 2D video image.
As a scheme for encoding a 3D video image, for example, a scheme in which a first-view-point video signal is encoded with the same scheme as that for a 2D video image and a second-view-point video signal is subjected to motion compensation by using a picture of a first-view-point video signal simultaneous with the second-view-point video signal as a reference picture is proposed (to be referred to as a disparity compensation scheme hereinafter) is proposed. In comparison with the encoding for a 2D video image, the scheme can advantageously encode a 3D video image without decreasing the resolutions of a first-view-point video signal and a second-view-point video signal.
As another example of the scheme for encoding a 3D video image, a scheme that horizontally reduces a first-view-point video signal and a second-view-point video signal into halves, respectively, arranges the reduced video signals from side to side, and encodes the video signals by the same scheme as that for a 2D video image is proposed. In this case, information representing that an encoding stream is a 3D video image is added to the header information of the encoding stream to discriminate a 2D video image encoding stream from a 3D video image encoding stream.
Patent Document 1 of a conventional technique describes an encoding apparatus that calculates quantized values such that a quantized value of an image (large parallax) on a front side is reduced and a quantized value of an image (small parallax) on a rear side is increased.