Multi-function USB capture chip using bufferless data compression

An apparatus for simultaneously performing vertical scaling and 4:2:2 to 4:2:0 color format conversion on incoming 4:2:2 color space component data of a video frame, the incoming color space component data having first color space component data, second color space component data, and third color space component data, the apparatus comprising:

• an accumulator having a first input operatively coupled to the incoming color space component data, a second input operatively coupled to an initializer value for rounding accumulated data, a third input operatively coupled to a component signal adapted for selecting the first, second, or third color space component to be scaled, a fourth input operatively coupled to a set_initial signal used to reset the accumulator, a fifth input for receiving intermediate accumulation results, and an output producing a sum of the incoming color space component data;
• a shifter having a first input operatively coupled to the accumulator output, a second input indicating a number of bits to shift the sum right, and an output;
• a multiplexer having a first input operatively coupled to the accumulator output, a second input operatively coupled to the shifter output, a select line operatively coupled to a final_shift signal indicating when a final shift is to be performed, and an output, the select line selecting the second input when the final shift is to be performed, and otherwise selecting the first input;
• and
• a buffer control module for storing the multiplexer output, the buffer control module adapted for providing the multiplexer output to a DCT module when the final_shift signal indicates the final shift is to be performed, and otherwise providing the multiplexer output to the fifth accumulator input.