An experimental system of the digital HDTV source compression codec at bitrates less than 22Mb/s is presented. It is based on the MPEG-2 standard. The emphasis is put on the adaptive frame/field Discrete Cosine Transformation(DCT)
frame/field scanning
the design of quantizer
the controlling strategy of bit-rate and buffer and the layer structure of bit-stream. A bit-stream completely consistent with MPEG-2 standard is produced. The subjective and objective assesments of restored pictures provide satisfactory results.