between the filtered value and the original signal value of the pixel then if the difference is less than the second predetermined threshold the picture quality improvement filter 40 determines that the pixel is noise and cancels the noise if the difference is larger than the second threshold the picture quality improvement filter 40 determines that the pixel is an edge not noise and recovers the original decoded value by adding the difference to the filtered value further further the picture quality improvement filter 40 compensates for a filtering caused decrease in the value of the edge in accordance with the exemplary embodiment of the present invention the picture quality improvement filter 40 determines the picture quality of the received video data by estimating the snr of the video data to which the present invention is not limited the picture quality level can be one of stepwise values matching to predetermined snr ranges for example picture quality levels 1 2 3 4 5 and 6 can be set respectively for an snr range from 0 to below 10 an snr range from 10 to below 20 an snr range from 20 to below 30 an snr range from 30 to below 40 an snr.