Moving image encoder and moving image decoder

摘要

A moving image encoder has an image separating unit (1) for generating four separate images (1)-(4) by sampling pixels constituting an input image every two alternate pixels in the horizontal direction and each alternate pixel in the vertical direction. An intraframe predictive coding unit performs intraframe predictive coding of the separate image (1) by using pixels constituting the separate image (1) produced by the image separating unit (1). An inter-separate image predictive coding unit 12 performs inter-separate image predictive coding of the separate images (2)-(4) produced by the image separating unit 1 by using the pixels constituting the separate image (1) produced by the image separating unit (1).

主权项

1. A moving image encoder comprising:
a separate image generating unit for producing a first separate image by sampling pixels constituting an input image at predetermined intervals, and for producing at least one second separate image by sampling pixels different from the foregoing pixels at predetermined intervals; an intraframe predictive coding unit for carrying out predictive coding of the first separate image within a frame by using the pixels constituting the first separate image produced by the separate image generating unit; an inter-separate image predictive coding unit for carrying out, between the first and second separate images, predictive coding of the second separate image produced by the separate image generating unit by using the pixels constituting the first separate image produced by the separate image generating unit; and a multiplexing unit for generating a bit stream by multiplexing coded data of the first separate image output from the intraframe predictive coding unit and coded data of the second separate image output from the inter-separate image predictive coding unit, wherein the intraframe predictive coding unit comprises: a first differential image output processing unit for generating a predictive image of the first separate image by executing intraframe prediction of the first separate image produced by the separate image generating unit on a block basis of a prescribed size, and for outputting a differential image between the first separate image and the predictive image; a first entropy coding processing unit for carrying out an orthogonal transform of the differential image output from the first differential image output processing unit on a block basis, and for performing entropy coding of orthogonal transform coefficients obtained as a result of the orthogonal transform; and a locally decoded image generation processing unit for producing a locally decoded image of the first separate image by performing an inverse orthogonal transform of the orthogonal transform coefficients and by adding a decoded predictive differential signal obtained as a result of the inverse orthogonal transform and the predictive image, and wherein the inter-separate image predictive coding unit comprises: a second differential image output processing unit for generating a predictive image of the second separate image produced by the separate image generating unit by using pixels constituting the locally decoded image of the first separate image produced by the locally decoded image generation processing unit, and for outputting a differential image between the second separate image and the predictive image; and a second entropy coding processing unit for carrying out an orthogonal transform of the differential image output from the second differential image output processing unit on a block basis, and for performing entropy coding of the orthogonal transform coefficients obtained as a result the orthogonal transform, and wherein the second differential image output processing unit of the inter-separate image predictive coding unit selects from a plurality of predictive modes a predictive mode suitable for correcting a shift in pixel positions between the first separate image and the second separate image produced by the separate image generating unit when generating the predictive image of the second separate image produced by the separate image generating unit, and generates the predictive image of the second separate image in that predictive mode, and the second entropy coding processing unit carries out entropy coding of the predictive mode selected by the second differential image output processing unit.