Moving picture converting apparatus and method, and computer program

A moving picture converting method of reconstructing an original picture from compressed moving-picture data, the method comprising the steps of:

• receiving compressed moving-picture data including a thinned image consisting of invalid pixels having values reduced and valid pixels keeping their values and a forward motion vector incident to the thinned image;
• interpolating the invalid pixels in a present frame to be restored on the basis of the valid pixels of the thinned image in the present frame to produce a padded image;
• and
• producing a rendered image by making preceding-frame rendering to restore pixels of the padded image on the basis of valid pixels in a preceding frame as a past frame in relation to the present frame and subsequent-frame rendering to restore pixels of the padded image on the basis of valid pixels in the subsequent frame as a future frame in relation to the present frame,
• in the preceding-frame rendering, a pixel at an end point of the tracing in the padded image being restored based on valid pixels detected in the process of tracing, started at a pixel in the preceding frame, in a sequence from the preceding frame to the present frame according to the forward motion vector, and
• in the subsequent-frame rendering, a pixel at the start point of the tracing in the padded image being restored based on valid pixels detected in the process of tracing, started at an invalid pixel of the padded image in the present frame, in a sequence from the present frame to the subsequent frame according to the forward motion vector.

A computer readable storage medium storing a computer program allowing a computer to carry out a moving picture converting method, the program comprising the steps of:

• receiving compressed moving-picture data including a thinned image consisting of invalid pixels having values reduced and valid pixels keeping their values and a forward motion vector incident to the thinned image;
• making intra-frame interpolation of the invalid pixels in a present frame to be restored on the basis of the valid pixels of the thinned image in the present frame to produce a padded image;
• and
• producing a rendered image by making preceding-frame rendering to restore pixels of the padded image on the basis of valid pixels in a preceding frame as a past frame in relation to the present frame and subsequent-frame rendering to restore pixels of the padded image on the basis of valid pixels in the subsequent frame as a future frame in relation to the present frame,
• in the preceding-frame rendering, a pixel at an end point of the tracing in the padded image being restored based on valid pixels detected in the process of tracing, started at a pixel in the preceding frame, in a sequence from the preceding frame to the present frame according to the forward motion vector, and
• in the subsequent-frame rendering, a pixel at the start point of the tracing in the padded image being restored based on valid pixels detected in the process of tracing, started at an invalid pixel of the padded image in the present frame, in a sequence from the present frame to the subsequent frame according to the forward motion vector.

A moving picture converting apparatus for reconstructing an original moving picture from compressed moving-picture data, the apparatus comprising:

• an input unit to receive compressed moving-picture data including a thinned image consisting of invalid pixels having values reduced and valid pixels keeping their values and a bidirectional motion vector incident to the thinned image;
• an intra-frame interpolator for interpolating the invalid pixels in a present frame to be restored on the basis of the valid pixels of the thinned image in the present frame to produce a padded image;
• and
• a frame rendering unit to produce a rendered image by making preceding-frame rendering to restore pixels of the padded image on the basis of valid pixels in a preceding frame as a past frame in relation to the present-frame rendering and subsequent-frame rendering to restore pixels of the padded image on the basis of valid pixels in the subsequent frame as a future frame in relation to the present frame,
• the frame rendering unit making
• the preceding-frame rendering to restore a pixel at an end point of tracing in the padded image on the basis of valid pixels detected in the process of tracing, started at an valid pixel of the padded image in the present frame, in a sequence from the preceding frame to the present frame according to a backward motion vector included in the bidirectional motion vector, and
• the subsequent-frame rendering to restore a pixel at the start point of tracing in the padded image on the basis of valid pixels detected in the process of tracing, started at an invalid pixel of the padded image in the present frame, in a sequence from the present frame to the subsequent frame according to a forward motion vector included in the bidirectional motion vector.