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Showing posts with the label mpeg

HDTV without the HDTV

About 5 years ago, I recall noticing the difference in quality between the signals that I received on non cable based tv from say 10 years ago and today's digital cable signals. The main difference lay in the fact that digital tv replaces ghost and snow artifacts for digital pixelization. In the early days I noticed a marked difference in quality as when both signals were at their best , the local cable provider applied enough compression to a signal that various scenes would clearly show the artifacts. The compression used on the digital signals is mostly mpeg format compression which uses a discrete cosine based method to compress luminance but mostly chrominance information to reduce the bandwidth requirements of the signal for transmission. However, cosine based compression is subject to quantization errors and artifacts having to do with the selection of a specific sized quantization kernel for the compression algorithm, for scene data that moves faster than the algorithm can ...