Method and apparatus for diagonal scan and simplified coding of transform coefficients

1. A method of encoding video data comprising:

providing a two dimensional array of transform coefficients representing a portion of video data;

determining a location of a last significant transform coefficient;

re-ordering at least a portion of the two dimensional array of transform coefficients to a one dimensional array of data by diagonally scanning the portion in at least two scan lines, each scan line directed in a single common diagonal direction;

generating a significance map comprising syntax elements indicating the location of the last significant transform coefficient and locations of additional non-zero transform coefficients in the one dimensional array;

representing at least a portion of the one dimensional array of data using a series of additional syntax elements;

coding the significance map syntax elements;

coding the series of additional syntax elements; and

transmitting the coded significance map syntax elements, and the arithmetic coded series of additional syntax elements.

2. The method of claim 1 , generating the significance map comprising:

generating the significance map comprising significant_coeff_flag, last_significant_coefficient_x, and last_significant_coefficient_y syntax elements.

3. The method of claim 1 , representing comprising:

representing the at least a portion of the one dimensional array of data using coeff_abs_level_greater1_flag, coeff_abs_level_greater2_flag, and coeff_sign_flag syntax elements.

4. The method of claim 1 , comprising:

determining the single common diagonal direction based on the determined location of the last significant transform coefficient.

5. The method of claim 1 , coding the significance map syntax elements comprising:

arithmetic coding the significance map syntax elements.

6. The method of claim 1 , coding the series of additional syntax elements comprising:

arithmetic coding the series of additional syntax elements.

7. A method of encoding video data comprising:

providing a two dimensional array of transform coefficients representing a portion of video data;

determining a location of a last significant transform coefficient based on the common diagonal scan direction;

re-ordering at least a portion of the two dimensional array of transform coefficients to a one dimensional array of data by diagonally scanning the portion in at least two scan lines, each scan line directed in a single common diagonal direction;

generating a significance map comprising syntax elements indicating the location of the last significant transform coefficient and locations of additional non-zero transform coefficients in the one dimensional array;

coding the significance map; and

transmitting the coded significance map syntax elements.

8. The method of claim 7 , generating the significance map comprising:

generating the significance map comprising significant_coeff_flag, last_significant_coefficient_x, and last_significant_coefficient_y syntax elements.

9. The method of claim 7 , comprising:

determining the single common diagonal direction based on the determined location of the last significant transform coefficient.

10. The method of claim 7 , coding the significance map syntax elements comprising:

arithmetic coding the significance map syntax elements.

11. A method of encoding video data comprising:

providing a two dimensional array of transform coefficients representing a portion of video data;

re-ordering at least a portion of the two dimensional array of transform coefficients to a one dimensional array of data by diagonally scanning the portion in at least two scan lines, each scan line directed in a single common diagonal direction;

representing at least a portion of the one dimensional array of data using a series of syntax elements;

coding the series of syntax elements; and

transmitting the coded syntax elements.

12. The method of claim 11 , representing comprising:

representing the at least a portion of the one dimensional array of data using coeff_abs_level_greater1_flag, coeff_abs_level_greater2_flag, and coeff_sign_flag syntax elements.

13. The method of claim 11 , comprising:

determining a location of a last significant transform coefficient;

determining the single common diagonal direction based on the determined location of the last significant transform coefficient.