Please help improve this article by adding citations to reliable sources.When the number of discrete symbols in a given stream is reduced, the stream becomes more compressible.
For example, reducing the number of colors required to represent a digital image makes it possible to reduce its file size. Specific applications include DCT data quantization in JPEG and DWT data quantization in JPEG 2000. Most bitmap editors and many operating systems have built-in support for color quantization. Popular modern color quantization algorithms include the nearest color algorithm (for fixed palettes), the median cut algorithm, and an algorithm based on octrees. This is done by simply dividing each component in the frequency domain by a constant for that component, and then rounding to the nearest integer. As a result of this, it is typically the case that many of the higher frequency components are rounded to zero, and many of the rest become small positive or negative numbers. Matlab Program For Uniform Quantization Encoding Meaning Code And DividedThe resulting block (the same size as the original block) is then pre-multiplied by the quantisation scale code and divided element-wise by the quantization matrix, and rounding each resultant element. The quantization matrix is designed to provide more resolution to more perceivable frequency components over less perceivable components (usually lower frequencies over high frequencies) in addition to transforming as many components to 0, which can be encoded with greatest efficiency. Many video encoders (such as DivX, Xvid, and 3ivx ) and compression standards (such as MPEG-2 and H.264AVC ) allow custom matrices to be used. Matlab Program For Uniform Quantization Encoding Meaning Full Quantizer MatrixThe extent of the reduction may be varied by changing the quantizer scale code, taking up much less bandwidth than a full quantizer matrix. By using a zig-zag ordering to group the non-zero entries and run length encoding, the quantized matrix can be much more efficiently stored than the non-quantized version. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
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