Error control codes for advanced television signals based upon preliminary and post filtering

Methods for the design and implementation of prefilters that can provide error control capability for ATV (advanced television) signals are described. The prefilters together with error estimators and optional postfilters implement outer codes that can be used with either digital or analog TV systems. The prefiltering accomplishes encoding without the addition of redundancy, but does introduce a small amount of distortion, often imperceptible. The computational requirements for the filtering are very modest, only 2 additions per pixel and P multiplications per column or diagonal line. A field store and a line buffer are required. A convenient algorithm is presented which can implement both vertical and diagonal filtering