Abstract: The present invention improves a digital signal processor, more particularly, calculation methods for motion compensation in reducing a required amount of calculations when an amount of distortion between a last frame block and a current frame block; in processing a direct memory access at a higher efficiency; in processing a subdivided data calculation at a higher speed; in processing a branch instruction occurring in the pipeline process at a higher efficiency; and in processing an interruption occurring in a repeat process operation at greater convenience, and furthermore in reducing a required amount of calculations through minimum distortion searching processes hierarchized.

Abstract: A video codec system inputs consecutively frame after frame of sub-sampled video data obtained by sub-sampling video data in units of frames. The video data is coded in parallel by internal coding circuits. This averages the numbers of significant pixels in the sub-sampled video data to be processed. The coded video data is composed so as to comply with specifications of the receiving equipment. Upon transmission, the data is again sub-sampled depending on the number of coding circuits on the receiving side. Each piece of the sub-sampled data is given a header for consecutive transmission. This allows for a certain period of time between pieces of data that arrive at the receiving side, thereby eliminating time differences in receiving and coding.

Abstract: An adaptive quantization coder/decoder having a limiter in a quantization coding module so that a reconstruction value of a quantization level is not in excess of a predetermined allowable range, or providing a limiter in a local quantization decoding module so that an output signal level falls within a predetermined allowable range, or providing a limiter in a quantization decoding module so that the output signal level falls within the predetermined allowable range.

Abstract: A digital signal processor of a simple circuit configuration capable of implementing arithmetic processes and interruption processes efficiently in a reduced number of steps at a high processing speed. The digital signal processor comprises instruction execution pipeline stages including a stage in which data is read from a data memory and the data is applied to an arithmetic unit; an arithmetic unit for the execution stage, including a barrel shifter, a multiplier and an arithmetic and logic unit, a normalizing barrel shifter, a round-off/accumulation adder, internal data memories and a DMA transfer bus for a write/accumulation stage, an address generating unit capable of parallel and two-dimensional generation of two inputs one output data memory addresses and a DMA control unit for controlling the two-dimensional data transfer through a DMA bus between the internal data memories and an external data memory for an instruction execution stage.