HDTV coding at below 45 Mbps for digital transmission

The authors describe a video coding scheme designed to transmit HDTV (high-definition television) signals at below 45 Mb/s over digital networks, such as the DS3 or the SONET fiber network. To achieve the required compression ratio of roughly 20:1, a combination of spatial and temporal processing and coding techniques was investigated. A spatial/temporal preprocessing scheme was first selected to reduce picture noise. Motion compensation with half-pixel accuracy and motion vector trimming were then applied. A previously investigated subband coding was adopted for signal decomposition. A novel 2D high-order entropy coding technique was used that resulted in significant improvement over the conventional run-length/variable-length entropy coding