Abstract: A hydrid encoder for video pictures comprising a motion estimator, and an inter-intraframe encoding selector which comprise a common calculation module. Known hybrid encoders for transmitting video pictures comprise a motion estimator and an inter-intraframe encoding selector. Due to the required high processing rate the motion estimator and the inter-intraframe encoding selector must have a parallel processing structure which leads to quite a considerable number of components. To this end a calculation module is proposed which can be used in the motion estimator and in the inter-intraframe encoding selector. Use of this invention, for example in hybrid encoders for video telephone apparatus.

Abstract: A predictive encoder for still pictures comprises a quantizer (Q) whose characteristic curve is variable. The encoded picture data are read and transmitted at a constant bit rate from an output memory (PMUX). A subtractor (SR) and a picture memory (BS) are used for obtaining prediction values. In order to be able to transmit the still pictures from a video camera without any noticeable loss of quality, a first frame memory (V1) is provided in which the data of all pixels of the still picture to be transmitted are stored. A selection circuit (AS) adjusts the characteristic curve after the quantizer (Q) performs the quantizing operation. If the data stored in the first frame memory (V1) are transmitted several times, the selection circuit (AS) selects, for each encoding and transmission operation, a characteristic curve corresponding to a more refined quantizing operation than the characteristic curve which was used for the previous encoding and transmission operation.