block for compensating the lost block application_number US 76983196 A description referring to fig1 a video signal is decoded at a decoding circuit 400 through the use of conventional decoding techniques such as a variable length decoding an inverse quantization and an inverse dct the video signal being divided into a multiplicity of blocks e g a block of n u00d7 m pixels with n and m being positive integers and the decoded video signal is stored at a frame memory 300 the video signal is also fed to a block detector 100 and the block detector 100 first checks a lost block in the video signal to thereby provide lost block information including position data representing the position of the lost block in the video signal onto a line l20 the lost block having lost or damaged pixel values and provides neighboring block information retrieved through a line l30 from the decoded video signal stored at the frame memory 300 based on the lost block information to an error concealment circuit 200 via a line l10 the neighboring block information including pixel values for each of neighboring blocks for the lost block the error concealment circuit 200 generates a substitution block for compensating the lost block within the video signal the substitution block being produced based on the neighboring block information on the line l10 from the block detector 100 in fig2 a and 2b there are represented detailed block diagrams of the error concealment circuit 200 shown in fig1 in accordance with the preferred embodiments of the present invention and a direction classification unit 210 commonly included in fig2 a and 2b is described in fig3 in more detail the structure of the error concealment circuit 200 and its operation will be.