Moving image encoding device, moving image encoding method, and computer program product

1. A moving image encoding method comprising:

dividing an input image of a digital image signal to be encoded into a plurality of small images including a first small image and a second small image such that a boundary area of the first small image overlaps that of the second small image;

performing an encoding operation in parallel on the small images obtained by the division to acquire encoded data;

combining the encoded data excluding an overlapping area; and

outputting the combined encoded data as encoded data of the input image, wherein the encoding operation comprises:

generating a difference value between the input small images and a prediction signal obtained by motion compensation prediction or in-screen prediction;

performing orthogonal transform on the difference value in a unit of an orthogonal transform block of a first size determined in advance or in a unit of an orthogonal transform block of a second size that is larger than the first size, thereby obtaining a transform coefficient;

performing quantization on the obtained transform coefficient, thereby generating a quantized signal;

adding a signal obtained by performing inverse quantization and inverse orthogonal transform on the quantized signal to the prediction signal, thereby generating a local decoding image signal;

performing filtering on the local decoding image signal based on the size of the orthogonal transform block, thereby reducing block noise;

dividing a screen of the local decoding image signal, in a horizontal direction or a vertical direction, such that each of the first small image and the second small image are divided into a first area serving as the overlapping boundary area, a second area that is adjacent to the first area, and a third area that is other than the first and second areas;

setting and instructing

to encode the first area of the first small image and the second area of the second small image with a same encoding parameter and

to encode the second area of the first small image and the first area of the second small image with a same encoding parameter; and

setting and instructing to perform orthogonal transform on the second area of the first small image and the first area of the second small image in the unit of the orthogonal transform block of the second size.

2. A non-transitory computer-readable medium storing a program causing a computer to execute the moving image encoding method according to claim 1 .