Patent US 6,101,313

An encoder considers a frame representing a picture as comprised of areas. For each area, the encoder decides which of frame-based or field-based orthogonal transformation will be most efficient at reducing spatial redundancy in that area. For each area, the encoder decides which of frame-based or field-based predictive encoding will be most efficient at reducing temporal redundancy in that area. The encoder encodes each area of the picture frame using the most efficient orthogonal transformation technique and using the most efficient predictive encoding technique to produce an encoded signal. A decoder decodes the encoded signal. The encoded signal is recorded on a recording medium, transmitted over a transmission channel, or broadcast.