Abstract: In a method and apparatus for scalably encoding in real time a sequence of digital video frames, a target digital processor class to be used for decoding the sequence is selected. A stillperiod value is selected in accordance with the selected target digital processor class. Every Nth frame of the sequence is then encoded as a still frame, and all other frames are encoded using interframe difference values, wherein N is equal to the stillperiod value.

Abstract: A single-instruction multiple-data video signal processor employs a dual-ported local memory architecture in each local memory including a dedicated port for transfers between the local memory and a global memory. A block transfer controller, in combination with the dedicated port, permit each access to the global memory by a datapath processor to be overlapped with its instruction processing, thus usually avoiding stalling of the video signal processor.

Abstract: A method and apparatus for partially encoding an image. The image is divided into a plurality of blocks and one block is selected for processing. A boundary lying along the selected block that is associated with a discontinuity is also selected. The errors associated with the selected block are reduced unevenly by a reduction factor that increases the degree to which the errors are reduced as the distance between the errors and the boundary increases. The selected block is encoded in accordance with the reduced errors.

Abstract: An apparatus for processing visual data includes a first video random access memory (VRAM) for storing a first bit plane of visual data in a first format. A graphics controller is coupled to the first VRAM by a data bus and a storage bus. The apparatus is capable of receiving at least a second VRAM for storing at least a second bit plane of visual data in at least a second format different from the first format. The received VRAMs are coupled to the graphics controller by data and storage busses. The visual data stored on the VRAMs are merged into a pixel stream which is then converted to analog form by a digital to analog converter. Data transfer addresses are generated for each of the VRAMs simultaneously, sequentially or in overlapping timed relationship.

Abstract: A request arbitration device is provided for prioritizing requests in a data processing system. A series of requests may arrive at the arbitration device at differing arrival times. The requests are accumulated to form a set of requests which is applied to a priority decode without any information on their relative arrival times. The priority device applies a fixed predetermined priority scheme to these requests. Simultaneously with the prioritizing of the first set of requests by the priority decode, a second set of requests may arrive at different arrival times. The requests of this second set of requests are likewise accumulated by the arbitration logic of a present invention. When arbitration of the first set of requests is complete, the second set of requests is then applied to the priority decode, again without any information with respect to their relative arrival times. The second set of requests is prioritized according to the same fixed predetermined priority scheme as the first set.

Abstract: An image having at least one high frequency feature is encoded by (a) filtering the image to produce a filtered image representing the image minus the at least one high frequency feature; (b) resolving the filtered image into at least one lower level of resolution; (c) encoding a correction image at the at least one lower level of resolution; (d) producing an expanded result image having the same the level of resolution of the image; and (e) encoding at the level of resolution the image the difference between the image and the expanded result image.

Abstract: A bitstream representative of at least one digital video image is decoded in real time by providing a code-book index from the bitstream, applying the code-book index to an index table to determine an index value, and comparing the index value to a first predetermined threshold. A single fixed statistical table is used for a plurality of images. If the index value is greater than the predetermined threshold, then at least one current pixel is determined by copying a corresponding previous pixel into the location of at least one current pixel; otherwise the index value is applied to a vector table to determine at least one vector value and a current pixel is determined from the vector value and a corresponding previous pixel. A digital video image is encoded in real time by selecting at least one pixel for encoding and determining at least one difference value between the selected pixel and at least one corresponding previous pixel.

Abstract: A method is provided for performing motion estimation in a system having a test image and a plurality of candidate images. A candidate image is selected and the difference between the test image and the selected candidate image is determined. The motion of an image is estimated according to this differencing and a determination is made of the duration of the motion estimation process in the system of the present invention. The candidate image selection, the differencing and the motion estimation are then repeated according to the duration determination. The duration determination may be a determination of a time duration or a determination of a number of machine cycles. The system is adapted to iteratively decrease a measurement of the error between the test image and selected candidate images as these actions are repeated. When the error stops decreasing and begins increasing the assumption is made in the system of the present invention that a best match has been determined.

Abstract: In a method and apparatus for scalably decoding a sequence of encoded digital video frames on a digital processor, an interpolation level is determined in accordance with the processing power of the digital processor. An encoded frame is selected from the sequence for decoding. If the interpolation level is greater than a predetermined threshold, then a scalably decoded frame is formed by interpolating the selected frame in accordance with a first pixel depth level. If the interpolation level is not greater than the predetermined threshold, then a scalably decoded frame is formed by interpolating the selected frame in accordance with a second pixel depth level, the second pixel depth level having fewer bits than the first pixel depth level.

Abstract: A bitstream representative of at least one digital video image is decoded in real time by providing a code-book index from the bitstream, applying the code-book index to an index table to determine an index value, and comparing the index value to a first predetermined threshold. If the index value is greater than the predetermined threshold, then at least one current pixel is determined by copying a corresponding previous pixel into the location of at least one current pixel; otherwise the index value is applied to a vector table to determine at least one vector value and a current pixel is determined from the vector value and a corresponding previous pixel. A digital video image is encoded in real time by selecting at least one pixel for encoding and determining at least one difference value between the selected pixel and at least one corresponding previous pixel. An index value corresponding to the location in a first table of the difference value is calculated.

Abstract: A method and apparatus for encoding an original image. The original image is divided into a plurality of regions and a region is selected therefrom for processing. A region energy value is determined in accordance with the magnitudes of the pixels in the selected region. The region energy value is compared to a threshold and a filtered image is formed by selectively zeroing the selected region in accordance with the comparison. The filtered image is resolved into at least one lower resolution image which is encoded. An expanded image is formed in accordance with the encoded lower resolution image, the expanded image being of the same level of resolution as the original image. An image representative of the difference between the original image and the expanded image is encoded at full resolution.

Abstract: A method and apparatus for encoding an original image. A first error image is formed from the original image and a first predicted image. A second error image is formed from the original image and a second predicted image. The first error image is resolved into at least one lower resolution image which is encoded. An expanded image is formed based on the encoded lower resolution image, the expanded image being of the same level of resolution as the second error image. An image representative of the difference between the second error image and the expanded image is encoded at full resolution.

Abstract: A method is disclosed for performing a discrete cosine transform on a transform input value wherein the discrete cosine transform has a plurality of predetermined transform coefficients. A number N.sub.1 of shift operations is determined independently of the transform input value in order to provide a set of N.sub.1 of shift operations. A number N.sub.2 of add operations is determined independently of the transform input value in order to provide a set of N.sub.2 add operations. The transform input value is operated upon only by the N.sub.1 shift operations and the N.sub.2 add operations to provide a discrete cosine transform output value without any multiplication. This method may be applied to both forward and inverse discrete cosine transforms. The transform coefficients are simplified coefficients which are provided by truncating and modifying prior art transform coefficients.

Abstract: A method and apparatus for compressing a dissolve region within a sequence of digital motion video frames. A function is calculated based on statistical data derived from frames in the sequence. Dissolve region boundaries are then detected based on characteristics of the calculated function. Consecutive detected boundaries may be flagged as a dissolve region based on the average value of the function between the consecutive detected boundaries and the distance between the consecutive detected boundaries.

Abstract: A method and apparatus for creating computer generated lines using a single or multiple instruction multiple data processor in conjunction with a modified version of Bresenham's line drawing algorithm wherein the speed of the operation is enhanced by allowing the processor to perform its memory writes in page mode.

Abstract: In a method of encoding a sequence of images of a digital motion video signal, information regarding future images in the image sequence is obtained by making an initial analysis of the image data before compression. The initial analysis provides information to the compression system regarding variations in complexity between images. This information is used to determine the setting of a compression controller. From this setting, other compression system thresholds and quantizers are scaled. In addition, the initial analysis provides qualitative information regarding events such as scene changes, brief periods of rapid motion, dissolves, wipes, and the appearance of a single anomalous image.

Abstract: A method and apparatus for encoding a sequence of digital motion video images at more than one resolution. In a first embodiment, it is determined whether an image selected from the sequence is part of either a dissolve, a fade, a fast motion region or a complex motion region. If the selected image is part of either a dissolve, a fade, a fast motion region or a complex motion region, then the selected image is encoded at a reduced resolution level. In a further embodiment, a selected image is provided for encoding. A determination is then made whether a parameter derived from an estimate of the available decoding time is above a predetermined threshold. If the parameter is above the predetermined threshold, then the selected image is encoded at a reduced resolution. In a still further embodiment, a selected image from a sub-sequence of images is provided for encoding. A determination is then made whether the quantization step size associated with the image is greater than a predetermined threshold.

Abstract: A method and apparatus for detecting a fade within a sequence of digital motion video frames. A first frame and a previous frame are selected from the sequence as first and second regions, respectively, for processing. The mean of the first region and the mean of the second region are each calculated and the relative mean change between the means is determined. A fade is detected if the relative mean change exceeds a first predetermined threshold. Alternatively, a fade is detected if the relative mean change is less than the first predetermined threshold but greater than a second predetermined threshold and the magnitude of the difference between the means is greater than a third predetermined threshold.

Abstract: A full motion color digital video signal is compressed, formatted for transmission, recorded on compact disc media and decoded at conventional video frame rates. During compression, regions of a frame are individually analyzed to select optimum fill coding methods specific to each region. Region decoding time estimates are made to optimize compression thresholds. Region descriptive codes conveying the size and locations of the regions are grouped together in a first segment of a data stream. Region fill codes conveying pixel amplitude indications for the regions are grouped together according to fill code type and placed in other segments of the data stream. The data stream segments are individually variable length coded according to their respective statistical distributions and formatted to form data frames.

Abstract: A video signal processor includes cicuitry which may be conditioned by a mode control signal to operate as a single 16-bit adder or as two eight-bit adders. The circuitry includes two eight-bit adders, each of which has a carry-in input terminal and a carry-out output terminal. The carry-out output terminal of one of the adders is selectively coupled, via an AND gate, to the carry-in input terminal of the other adder. The AND gate is controlled by the mode control signal. In the mode where the circuitry operates as two eight-bit adders, additional circuiry is included to detect output values which may exceed the zero to 255 range of valid values and to saturate these invalid values either at zero or 255.