Video compression and encoding method
Disclosed herein is a method for decoding a video signal having at least one frame with a plurality of blocks including a current block, including generating, for at least a selected pixel in the current block, a predicted value for at least one pixel located in a row i and a column j of the current block using a processor and according to the following equation: X ij =L i +A j −C; wherein X ij is the predicted value, L i is the value of a pixel to the left of the current block, A j is the value of a pixel in a row above the current block and C is the value of a pixel in the row above and the column to the left of the current block and decoding the current block using the predicted value.
1. A method for decoding a frame in a video stream, the frame having a plurality of blocks, the method comprising:
identifying, using a motion vector associated with a current block in the frame, a block in a reference frame;
determining if the motion vector includes at least one fractional component;
if the motion vector includes the at least one fractional component, applying a 6-tap interpolation filter to the block in the reference frame to form a predictor block using a processor;
wherein coefficients of the 6-tap interpolation filter are selected from at least one of the following:
{2, −11, 108, 36, −8, 1} for ¼ pixel position;
{3, −16, 77, 77, −16, 3} for ½ pixel position; or
{1, −8, 36, 108, −11, 2} for ¾ pixel position; and
decoding the current block using the predictor block.
2. The method of claim 1 , wherein the 6-tap interpolation filter is a two-dimensional filter including a horizontal dimension and a vertical dimension.
3. The method of claim 2 , wherein applying the 6-tap interpolation filter to the block in the reference frame to form the predictor block comprises:
filtering the block in the horizontal dimension and then in the a vertical dimension to form the predictor block.
4. The method of claim 1 , wherein applying the 6-tap interpolation filter to the block in the reference frame to form the predictor block comprises:
filtering the block in the vertical dimension and then in the horizontal dimension to form the predictor block.
5. The method of claim 1 , further comprising:
selecting the 6-tap interpolation filter from a plurality of interpolation filters.
6. The method of claim 5 , wherein the plurality of interpolation filters includes at least one of a bi-linear filter or a bi-cubic filter.
7. The method of claim 1 , wherein the motion vector includes a horizontal displacement component and a vertical displacement component and wherein determining if the motion vector includes the at least one fractional component comprises:
determining if the horizontal displacement component of the motion vector includes a fractional component; and
determining if the vertical displacement component of the motion vector includes a fractional component.
8. The method of claim 7 , applying the 6-tap interpolation filter to the block in the reference frame to form the predictor block, comprises:
horizontally interpolating the predictor block using the 6-tap interpolation filter if the horizontal component includes the fractional component.
9. The method of claim 8 , applying the 6-tap interpolation filter to the block in the reference frame to form the predictor block, comprises:
vertically interpolating the horizontally interpolated predictor block using the 6-tap interpolation filter if the vertical component includes the fractional component.
10. The method of claim 7 , applying the 6-tap interpolation filter to the block in the reference frame to form the predictor block, comprises:
vertically interpolating the predictor block using the 6-tap interpolation filter if the vertical component includes the fractional component.
11. The method of claim 8 , applying the 6-tap interpolation filter to the block in the reference frame to form the predictor block, comprises:
horizontally interpolating the vertically interpolated predictor block using the 6-tap interpolation filter if the horizontal component includes the fractional component.
12. An apparatus for decoding a frame in a video stream, the frame having a plurality of blocks, the apparatus comprising:
means for identifying, using a motion vector associated with a current block in the frame, a block in a reference frame;
means for determining if the motion vector includes at least one fractional component;
if the motion vector includes the at least one fractional component, means for applying a 6-tap interpolation filter to the block in the reference frame to form a predictor block;
wherein coefficients of the 6-tap interpolation filter are selected from at least one of the following:
{2, −11, 108, 36, −8, 1} for ¼pixel position;
{3, −16, 77, 77, −16, 3} for ½ pixel position; or
{1, −8, 36, 108, −11, 2} for ¾pixel position; and
means for decoding the current block using the predictor block.
13. The apparatus of claim 12 , wherein the 6-tap interpolation filter is a two-dimensional filter including a horizontal dimension and a vertical dimension.
14. The apparatus of claim 13 , wherein the means for applying the 6-tap interpolation filter to the block in the reference frame to form the predictor block comprises:
means for filtering the block in the horizontal dimension and then in the a vertical dimension to form the predictor block.
15. The apparatus of claim 13 , wherein the means for applying the 6-tap interpolation filter to the block in the reference frame to form the predictor block comprises:
means for filtering the block in the vertical dimension and then in the horizontal dimension to form the predictor block.
16. The method of claim 7 , further comprising:
means for selecting the 6-tap interpolation filter from a plurality of interpolation filters.
17. The method of claim 11 , wherein the plurality of interpolation filters includes at least one of a bi-linear filter or a bi-cubic filter.
18. A method for decoding blocks of pixels using a processor, comprising:
determining the location of a block in a previously decoded reference frame to be used as a predictor block, relative to the spatial position of a block being predicted, using a motion vector, wherein the motion vector is one of ½ and ¼pixel precision in the luma domain and one of ¼ and ⅛ pixel precision in the chroma domain;
applying a 6-tap 2 dimensional interpolation filter to the predictor block using the processor, whose coefficients, when implemented as a separable 2-dimensional filter such that the predictor block is first filtered in one of a horizontal and vertical dimension and the resulting filtered block is then filtered in the other dimension, are as follows:
{2, −11, 108, 36, −8, 1} (¼pixel)
{3, −16, 77, 77, −16, 3} (½ pixel)
{1, −8, 36, 108, −11, 2} (¾pixel).
19. The method of claim 1 , further comprising:
selecting the 6-tap interpolation filter from a plurality of interpolation filters.
20. The method of claim 1 , wherein the plurality of interpolation filters includes at least one of a bi-linear filter or a bi-cubic filter.