In accordance with an illustrative embodiment of the invention, a composite video signal is decoded as follows. A filtered and optionally re-sampled luminance component is obtained by vertical low-pass filtering the composite video signal using a vertical low-pass filter. The vertical low-pass filter may also be a re-sampler so that the output is optionally a filtered and re-sampled luminance signal. (Note that the use of a single vertical low-pass filter and re-sampler is more efficient than the prior art which uses a luma comb filter followed by a vertical filter/re-sampler to obtain the filtered and optionally re-sampled luminance component). Filtered and re-sampled chrominance components are obtained by first vertically high-pass filtering and re-sampling the composite video signal using a vertical high pass filter/re-sampler. This results in filtered and re-sampled but still quadrature modulated chroma signals. These signals are then demodulated and horizontal low-pass filtered to obtain separate filtered and re-sampled chroma components. (Note this process is more efficient than the prior art which utilizes a chroma comb filter, a demodulator, and a vertical filter/re-sampler to obtain the filtered and re-sampled chroma components). In short, the present invention eliminates the need to directly obtain the Y, U, and V components and then vertically filter and re-sample the Y, U, and V components. Instead, according to the invention, the vertically filtered and re-sampled Y, U, and V components are directly obtained.
A color signal reproducing circuit having A/D converter 101, sync separator 102, YC separator 103, gain controller 105, multipliers 106 and 107, low-pass filters 108 and 109, burst-period cumulative adders 110 and 111, SINCOS generator 112, clock generator 113, and ramp-wave generator 114. The simple structure allows a color signal reproducing circuit to be used commonly in a different television systems without changing its clock frequency considerably in accordance with broadcasting systems and also achieves YC separation and color signal demodulation from analog composite signal with a higher degree of precision.
Systems and methods are provided for detecting motion within a composite video signal. A first chroma difference element compares an in-phase chroma component of the composite video signal to a delayed representation of the in-phase chroma component to produce a first chroma difference value for a given pixel. A second chroma difference element compares a quadrature chroma component of the composite video signal to a delayed representation of the quadrature chroma component to produce a second chroma difference value for the pixel. A parameter mapping component maps the first and second difference values to respective first and second motion parameters that indicates the degree of change in the chroma properties of the pixel. A parameter selector determines a composite motion parameter for the pixel from the first and second motion parameters.
Systems and method are provided for luma-chroma separation. A demodulator system demodulates a composite video signal to produce at least two baseband chroma signals. A given baseband chroma signal contains chroma information for one of a plurality of video frames comprising the composite signal. A three-dimensional (3-D) comb filter removes luma information from a given baseband chroma signal by combining sets of at least two baseband chroma signals to form a 3-D filtered baseband signal.
Systems and methods are provided for correcting color phase error in a video decoder system. A demodulator system demodulates the composite input signal and the at least one delayed signal to produce sets of baseband chroma components based on a phase correction value. Color phase correction logic determines the phase correction value for the demodulator system based upon characteristics of the baseband chroma components associated with a series of at least two consecutive frames.
A technique is provided for programmably vertically filtering pixel values of frames of a sequence of video frames. The technique includes separating luminance components and chrominance components of the pixel values within a vertical filter buffer, then vertically filtering luminance components of the pixel values using programmable luminance filter coefficients, and vertically filtering chrominance components of the pixel values using programmable chrominance filter coefficients. The filtered luminance component data and filtered chrominance component data is subsequently merged onto a single luminance/chrominance bus for further filtering and/or encoding. The luminance and chrominance filter coefficients are programmable and may be changed dynamically and repeatedly at picture boundaries. In one embodiment, the programmable vertical filter includes a four tap luminance component filter and a five tap chrominance component filter.
