CODER FOR VIDEO SIGNAL

摘要

PURPOSE:To attain accurate chromakie synthesis with respect to a video signal after decoding by applying coding to a picture part including an edge of a key color with high picture quality in the coder sending or storing a video signal having source quality. CONSTITUTION:A luminance signal and a chroma signal are inputted to orthogonal transformation coding means 120, 121 in the unit of a picture element block respectively. A quantization step width of the orthogonal transformation coding means 120, 121 is controlled based on the presence of a preset key color in a picture element block and edge information in the picture element block obtained from the transformation coefficients of high frequency regions of both the signals. After the quantization, video data by the luminance signal and the chroma signal are multiplexed and sent or stored via a buffer memory 170.