Method and apparatus for providing 64-bit YUV to RGB color conversion
AssigneeCompaq Computer Corporation
InventorsRobert A. Ulichney, William I. Hallahan
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Abstract
A method of providing conversion from YUV signals to RGB signals includes the steps of determining a correspondence value between each of the Y, U, and V pixel values and the corresponding one of the R, G, and B pixel values. Three tables are generated; a Y table, a U table and a V table. During operation, each table may then be easily accessed by indexing the table with the respective Y, U or V input, to provide R,G,B data. The method may be used in a 64 bit embodiment using two registers or one register. Alternatively, the method may be used in a 32 bit embodiment. The conversion method can easily be augmented to provide color adjustment during conversion without any added complexity.
Claims16
A method for converting digital pixel data from an input YUV format to an RGB format via the following the equations:
- R1=(VR)V;
- G1=(G0u)U+(G0v)V;
- and B1=(UB)U, and R=Y+R1, G=Y+G1, and B=Y+B1, the method comprising the steps of:
- calculating the values from the above equations, wherein said calculation results in integer values for four corresponding tables, R1, G0u, G0v, and B1;
- limiting each and every value of the R1, G0u, G0v, B1 and Y values to a predetermined number of bits;
- combing the R1 and G0v to form a V table;
- combining the B1 and G0u to form a U table;
- and replicating the Y value three times in a table, wherein when addressed the three values are fetched in parallel,
- determining if the UV signal is signed, if unsigned;
- converting each unsigned U and V value to a signed value;
- addressing the U and V tables with the signed UV inputs and addressing the Y table with the Y input, and
- combining the outputs of the U and V tables and then combining the result with the outputs of the Y table as defined in the above equations to form the RGB format.
Apparatus for converting digital pixel data from an input YUV format to an RGB format via the following the equations:
- R1=(VR)V;
- G1=(G0u)U+(G0v)V;
- and B1=(UB)U, and R=Y+R1, G=Y+G1, and B=Y+B1, the apparatus comprising:
- means for calculating the component values from the above equations, wherein said calculation results in integer values for four corresponding tables R1, G0u, G0v, and B1;
- means for limiting each and every value of the R1, G0u, G0v, B1 and Y values to a predetermined number of bits;
- a V table formed by combing the R1 and G0v;
- a U table formed by combining the B1 and G0u;
- and a Y table holding Y values replicated three times, wherein when addressed the three values are fetched in parallel;
- means for determining if the UV signal is signed, if unsigned;
- means for converting each unsigned U and V value to a signed value;
- means for addressing the U and V tables with the signed UV inputs and for addressing the Y table with the Y input, and
- means for combining the outputs of the U and V tables with the output of the Y table as defined in the above equations to form the RGB format.
Dependencies are inferred from the claim text.