Method and apparatus for encoding interlaced macroblock texture information

Abstract

A method for padding interlaced texture information on a reference VOP to perform a motion estimation detects whether said each texture macroblock of the reference VOP is a boundary block or not. After the undefined texture pixels of the boundary block are extrapolated from the defined texture pixels thereof by using a horizontal repetitive padding, a transparent row padding and a transparent field padding sequentially, an undefined adjacent block is expanded based on the extrapolated boundary block.

1. A method for encoding interlaced texture information on a texture macroblock basis through a motion estimation between a current VOP and its one or more reference VOP's, wherein each texture macroblock of the current and the reference VOP's has M×N defined or undefined texture pixels, M and N being positive even integers, respectively, the method comprising the steps of:
 (a) detecting whether said each texture macroblock of each reference VOP is a boundary block or not, wherein the boundary block has at least one defined texture pixel and at least one undefined texture pixel; 
 (b) dividing the boundary block into two field blocks, each field block having M/2×N texture pixels; 
 (c) extrapolating the undefined texture pixels of each field block based on the defined texture pixels thereof to generate an extrapolated boundary block for said two field blocks; 
 (d) if the boundary block has an undefined field block and a defined field block, padding the undefined field block based on the defined field block, wherein the undefined field block and the defined field block represent one field block having the undefined texture pixels only and the other field block having at least one defined texture pixel, respectively; and 
 (f) expanding an undefined adjacent block based on the extrapolated boundary block, wherein the undefined adjacent block is adjacent to the extrapolated boundary block and has only undefined texture pixels, 
 wherein the step (c) further includes the step of (c1) field-padding said at least one undefined texture pixel in a field block from said at least one defined texture pixel therein, to thereby generate a padded field block for the field block, 
 wherein the step (c1) has the steps of:
 (c11) row-padding said at least one undefined texture pixel on a row-by-row basis to generate a padded row; and 
 (c12) padding, if there exists a transparent row, the transparent row from at least one nearest padded row, wherein the transparent row represents a row having the undefined texture pixels only. 
 
 
     
     
       2. The method as recited in  claim 1 , wherein said step (f) includes the steps of:
 (f1) selecting, if said undefined adjacent block is surrounded by a plurality of extrapolated boundary blocks, one of the left, the upper, the right and the below extrapolated boundary blocks of said undefined adjacent block in this priority; and 
 (f2) replicating a vertical or a horizontal border of the selected extrapolated boundary block rightwards, downwards, leftwards or upwards, to thereby expand the undefined adjacent block, wherein the vertical or the horizontal border adjoins said undefined adjacent block. 
 
     
     
       3. The method as recited in  claim 1 , wherein all the undefined texture pixels of said undefined field block are padded with a constant value. 
     
     
       4. The method as recited in  claim 3 , wherein all the undefined texture pixels of said undefined field block are padded with a mean value of both the defined texture pixels and padded texture pixels within the padded field block for the other field block, wherein the padded texture pixels are field-padded through the step (c1). 
     
     
       5. The method as recited in  claim 3 , wherein all the undefined texture pixels of said undefined field block are padded with a mean value of the defined texture pixels within the padded field block for the other field block. 
     
     
       6. The method as recited in  claim 3 , wherein the constant value is 2 L−1 , wherein L is the number of bits assigned for each pixel. 
     
     
       7. The method as recited in  claim 6 , wherein L is 8. 
     
     
       8. An apparatus for encoding interlaced texture information on a texture macroblock basis through a motion estimation between a current VOP and its one or more reference VOP's, wherein each texture macroblock of the current and reference VOP's has M×N texture pixels, M and N being positive even integers, respectively, the apparatus comprising:
 a boundary block detector for detecting whether said each texture macroblock of each reference VOP is a boundary block or not, wherein the boundary block has at least one defined texture pixel and at least one undefined texture pixel; 
 a field divider for dividing the boundary block into two field blocks, each field block having M/2×N texture pixels; 
 a texture pixel padding circuit for extrapolating the undefined texture pixels of each field block based on the defined texture pixels thereof to generate an extrapolated boundary block for said two field blocks; 
 a transparent field padding circuit for padding an undefined field block of the boundary block based on the other field block thereof, wherein the undefined field block represents a field block having the undefined texture pixels only; 
 an adjacent block padding circuit for expanding an undefined adjacent block based on the extrapolated boundary block, wherein the undefined adjacent block is adjacent to the extrapolated boundary block and has the undefined texture pixels only; and 
 a field-padding circuit for field-padding the undefined texture pixels in a field block from the defined texture pixels therein, to thereby generate a padded field block for the field block, wherein the field-padding circuit includes:
 a horizontal padding circuit for padding the undefined texture pixels on a row-by-row basis to generate a padded row; and 
 a transparent row padding circuit for padding the transparent row from at least one nearest padded row, wherein the transparent row represents a row having the defined texture pixels only. 
 
 
     
     
       9. The apparatus as recited in  claim 8 , wherein said adjacent block padding circuit includes:
 a selector for selecting one of the left, the upper, the right and the below extrapolated boundary blocks of said undefined adjacent block in this priority; and 
 means for replicating a vertical or a horizontal border of the selected extrapolated boundary block rightwards, downwards, leftwards or upwards, to thereby expand the undefined adjacent block, wherein the vertical or the horizontal border adjoins said undefined adjacent block. 
 
     
     
       10. The apparatus as recited in  claim 8 , wherein all the undefined texture pixels of said undefined field block are padded with a constant value. 
     
     
       11. The apparatus as recited in  claim 10 , wherein all the undefined texture pixels of said undefined field block are padded with a mean value of both the defined texture pixels and padded texture pixels within the padded field block for the other field block, wherein the padded texture pixels are field-padded through the field-padding circuit. 
     
     
       12. The apparatus as recited in  claim 10 , wherein all the undefined texture pixels of said undefined field block are padded with a mean value of the defined texture pixels within the padded field block for the other field block. 
     
     
       13. The apparatus as recited in  claim 10 , wherein the constant value is 2 L− , L being the number of bits assigned for each pixel. 
     
     
       14. The apparatus as recited in  claim 13 , wherein L is 8. 
     
     
       15. An apparatus for encoding interlaced texture information on a texture macroblock basis using a field prediction between a current VOP and one or more reference VOP's, the apparatus comprising:
 a motion estimator configured to determine a field motion vector for each current top or bottom field block on a field-by-field basis, the each current top or bottom field block comprising undefined texture pixels and defined texture pixels;   a motion compensator configured to provide a predicted top or bottom field block for each current top or bottom field block;   a subtractor configured to subtract the predicted top or bottom field block from each current top or bottom field block on a corresponding pixel-by-pixel basis to obtain the error field block;   a texture encoding circuit configured to discrete-cosine transform the error field block on a DCT block-by-DCT block basis, and to quantize the discrete-cosine-transformed coefficients;   a statistical encoding circuit configured to perform a statistical encoding on the quantized coefficient fed from the texture encoding circuit and the field motion vector for each current top or bottom field block fed from the motion estimator;   a texture reconstruction circuit configured to perform an inverse quantization and inverse transform on the quantized transform coefficients to obtain a reconstructed error field block;   an adder configured to combine the reconstructed error field block from the texture reconstruction circuit and the predicted top or bottom field block from the motion compensator on a pixel-by-pixel basis; and   a reference frame processing circuit configured to pad a reconstructed top or bottom field block based on shape information for the current VOP, to thereby store the padded top or bottom field blocks as reference interlaced texture information, the reference frame processing circuit comprising:
 a texture pixel padding circuit configured to extrapolate the undefined texture pixels based on the defined texture pixels to generate an extrapolated boundary block for the top or the bottom field block; 
 a transparent field padding circuit configured to pad an undefined field block of the extrapolated boundary block based on the other field block thereof, wherein the undefined field block represents a field block comprising the undefined texture pixels only; 
 an adjacent block padding circuit configured to expand an undefined adjacent block based on the extrapolated boundary block, wherein the undefined adjacent block is adjacent to the extrapolated boundary block and has the undefined texture pixels only; 
 a field-padding circuit configured to pad the undefined texture pixels in a field block from the defined texture pixels therein, to thereby generate a padded field block for the field block; 
 a transparent row padding circuit configured to pad the transparent row from at least one nearest padded row, wherein the transparent row represents a row having the defined texture pixels only; 
 a first padding device configured to pad the undefined texture pixel in a row of the field block having at least one defined texture based on one or more of the defined texture pixels in said row, 
 a second padding device configured to pad the undefined texture pixel in a row of the field block having at least one defined texture based on one or more of the defined texture pixels in another one or more rows in said field block, and 
 a third padding device configured to pad the field block of boundary VOP having only the undefined texture pixels with a constant value. 
   
     
     
       16. The apparatus of claim 15, wherein the reference frame processing circuit further comprises:
 an adjacent macroblock padding circuit for expanding an undefined adjacent macroblock based on the padded boundary macroblock, wherein the undefined adjacent macroblock is adjacent to the padded boundary macroblock and has only undefined texture pixels, and   a remaining macroblock padding circuit for padding the exterior macroblock not adjacent to the padded boundary macroblock with a constant value.   
     
     
       17. The apparatus of claim 15, wherein the constant value is 2 L−1 , and L is a number of bits assigned for each pixel. 
     
     
       18. The apparatus of claim 15, wherein said padding of the field block with a constant value includes padding said field block with a constant value of 128.