Method and apparatus for generating RGB color signals from composite digital video signal

In a method for converting a bit stream representing a color video signal to red, green, and blue (RGB) color control signals for a RGB monitor or color printer where consecutive fields of bits in said bit stream represent codes for predetermined colors, an improvement comprising the steps of:

• examining fields of bits in said bit stream to determine when a color change occurs;
• examining fields of bits in said bit stream to determine said predetermined colors;
• using one of the predetermined colors detecting prior to said determination of said color change until the passage of a certain number of bits is detected in said bit stream, then switching to the changed color;
• whereby better transition from one color to another color results.

In a method for converting a bit stream representing a composite color video signal to red, green and blue (RGB) color control signals for a RGB color monitor or a color printer where consecutive fields of n bits in said bit stream represent codes for predetermined colors, an improvement comprising the steps of:

• determining from changing patterns of bits in said bit stream when a color change is occurring;
• examining fields of n bits where a new field of n bits is formed for every bit in said bit stream, said examining being used to detect one of said predetermined colors;
• using one of the predetermined colors detected prior to said determination of said color change until said color change is complete;
• whereby better transition from one color to another color occurs.

In a method for converting a bit stream representing a composite color video signal to a parallel control signals for a color monitor or color printer where consecutive color fields in said bit stream represent codes for predetermined colors and wherein each field comprises a certain number of bits, an improvement comprising;

• comparing the nth bit of one of said fields with the nth bit of the next of said fields;
• detecting a change in said nth bits of said one field and said next field;
• and,
• maintaining the color associated with said one field when said change is detected, then switching to the changed color;
• whereby better transition from one color to another color occurs.

In a method for converting a bit stream representing a composite color video signal to red, green and blue (RGB) color control signals for a RGB color monitor or color printer where each four bit field in said bit stream represents codes for a predetermined color, an improvement comprising the steps of:

• determining from changing patterns of bits in said bit stream when a color change occurs;
• examining groups of four bits where a group of four bits is formed for every new bit in said bit stream for detecting said predetermined colors;
• using one of the predetermined colors detected prior to said determination of said color change until the passage of a certain number of bits is detected, then switching to the changed color;
• whereby better transition from one color to another color results.

In an apparatus for converting a serial bit stream representing color codes of a video signal to parallel control signals for a video display, an improvement comprising:

• comparator means for comparing bits in said field to detect when a color change occurs;
• examination means for loading bits from said serial bits stream and examining consecutive bit fields of said bit stream to detect predetermined colors, coupled to said comparator means;
• control means coupled to said comparator means and said examination means for substituting the one of said predetermined colors detected prior to said color change until the passage of a certain number of bits is detected and for switching to the next color;
• whereby smooth transition from one color to another results.

An apparatus for converting a serial bit stream representing color codes of a composite video signal to parallel control signals for a color monitor or color printer comprising:

• a shift register for receiving said bit stream and for providing a first parallel output;
• a barrel shifter coupled to said shift register for receiving said parallel output, said barrel shifter providing a second parallel output;
• comparator means for comparing said bit stream coupled to said shift register and one of said first parallel outputs of said shift register, said comparator means providing a control signal;
• multiplexer means coupled to said second parallel output for receiving a first input from said barrel shifter;
• storage means for storing a digital signal coupled to the output of said multiplexer, the output of said storage means being coupled to the input of said multiplexer so as to provide a second input to said multiplexer;
• said multiplexer being controlled by said control signal from said comparator means, said multiplexer for providing either said first input or said said second input as an output;
• whereby the output of said storage means is recirculated through said multiplexer means when said color change occurs providing for a smooth color transition.