Inter/intraframe coding of color TV signals for transmission at the third level of the digital hierarchy

The data rate of the third level of the digital hierarchy is regarded as particularly economical for the international exchange of television programs via satellite. Nonetheless, the exchange is aggravated by the fact that this level has not been standardized on a world-wide scale. For example, a rate of 32 Mbits/s is used in Japan, 34 Mbits/s in Europe, and 44 Mbits/s in North America. The present paper details a procedure which allows digital TV signals of studio standard to be transmitted on 32-, 34-, or 44-Mbit/s channels by means of sampling rate conversion and adaptive source coding. For the case where an international link consists of sections using different data rates, a transcoding method is described and tested in computer simulations which converts the third-level rates into each other, without cascading of DPCM-decoders and-encoders.