Abstract: A GOP-independent dynamic bit-rate controller system includes a user interface to receive one or more input parameters, a bit-rate controller and an encoder. The bit-rate controller regulates a bit-rate of an output bit-stream. The bit-rate controller includes multiple bit-rate modules to determine a bit-estimate and a quantization parameter, and a control module to calculate a convergence period based on the received input parameters and a frame rate. The control module selects a bit rate module based on the convergence period and the encoder generates the output bit-stream using the quantization parameter determined by the bit rate module.

Abstract: A moving-image signal, such as typically a luminance signal organized in blocks of pixels is coded via a technique that envisages the steps of: comparing a block to be coded with a plurality of candidate prediction blocks; determining, for each candidate prediction block, a respective value of an index representing the difference between the block to be coded and each candidate prediction block; and choosing between the candidate prediction blocks, as a function of the respective value of the aforesaid index, a prediction block to be used for coding of the block to be coded. The signal is sampled pixel by pixel on the block to be coded and on the plurality of candidate prediction blocks, thus generating respective surfaces representing the pattern of the signal in the block to be coded and in the candidate prediction blocks. Chosen as an index is an index of the parallelism between the aforesaid respective surfaces.

Abstract: A spatial-type de-interlacing process to be applied to a digital image for obtaining a spatial reconstruction. Furthermore, to the digital image there are also applied one or more temporal-type motion compensation de-interlacing processes for obtaining one or more temporal reconstructions, and the spatial reconstruction and the one or more temporal reconstructions are sent to a decision module. The decision module applies a cost function to the spatial reconstruction and the temporal reconstructions and chooses from among the spatial reconstruction and the temporal reconstructions the one that minimizes the cost function. Preferential application is to display systems, in particular displays of a cathode-ray type, liquid-crystal type, and plasma type which use a mechanism of progressive scan.

Abstract: A process for format conversion of DCT macroblocks in an MPEG video bitstream that are divided into blocks, each of which includes a plurality of microblocks. In each DCT block, the significant frequencies are identified and preserved, isolating a corresponding microblock preferably consisting of the microblock on the top left of each block and setting to zero the coefficients of the remaining microblocks. On the microblock thus isolated there is performed an inverse discrete cosine transform, and the microblock thus obtained is merged with the homologous microblocks obtained from the other blocks comprised in a respective starting macroblock, so as to give rise to a merging block. The merging block thus obtained undergoes a discrete cosine transform so as to obtain a final block, which can be assembled into a macroblock with converted format.

Abstract: A process and a system is described for generating an MPEG output bitstream starting from an MPEG input bitstream. The output bitstream has a resolution modified with respect to the resolution of the input bitstream. In the input bitstream, first portions that substantially do not affect and second portions that do affect resolution variation are distinguished. The second portions are then subjected to a function of modification of the resolution obtained by filtering the second portions in a domain of the discrete cosine transform, and then are transferred to the output bitstream. A corresponding computer program product is also provided.

Abstract: A moving-image signal, such as typically a luminance signal organized in blocks of pixels is coded via a technique that envisages the steps of: comparing a block to be coded with a plurality of candidate prediction blocks; determining, for each candidate prediction block, a respective value of an index representing the difference between the block to be coded and each candidate prediction block; and choosing between the candidate prediction blocks, as a function of the respective value of the aforesaid index, a prediction block to be used for coding of the block to be coded. The signal is sampled pixel by pixel on the block to be coded and on the plurality of candidate prediction blocks, thus generating respective surfaces representing the pattern of the signal in the block to be coded and in the candidate prediction blocks. Chosen as an index is an index of the parallelism between the aforesaid respective surfaces.

Abstract: An RGB digital video signal destined to be displayed on a display such as a liquid crystal display (LCD) is converted from the RGB color space to the YUV color space. The signal converted into the YUV color space is subjected to at least a processing operation selected among a sub-sampling operation (24) and a data compression operation (26). The signal is then stored in a memory and the signal read from said memory (12) is then subjected to at least a return operation (28, 30) complementary to the aforesaid processing operation (24, 26). The signal subjected to the aforesaid return operation is lastly reconverted from the YUV color space to the RGB color space, thus being susceptible to be displayed on the display.

Abstract: Transcoder apparatus for transcoding an input video bit-stream having a first encoding profile (e.g., MPEG-2) into an output video bit-stream having a second encoding profile (e.g., H.264), the first encoding profile including motion estimation information, the apparatus including: a front-end for extracting the motion estimation information from the input video bit-stream, and a back-end for constructing the output bit-stream. The front-end and the back-end of the apparatus are interconnected (e.g., via a buffer) to pass the motion estimation information from the front-end to the back-end, thereby avoiding motion estimation in constructing the output bit-stream at the apparatus back-end.

Abstract: A coprocessor circuit for processing image data in digital form, having a motion vector controller block for generating, starting from the image data, motion vector values that include predictor data and macroblock data relating to a current macroblock of the image data to be estimated and being adapted to be stored at respective memory addresses. Also included is an address generator block for extracting respective addresses from the motion vector values, a predictor fetch block for retrieving predictor data based on respective addresses extracted by the address generator block, a current macroblock fetch and distengine block for retrieving macroblock data based on respective addresses extracted by the address generator block and for processing the macroblock data according to a given function, and a decision block for collecting the retrieved data as partial results and selecting the best result therefrom.

Abstract: A method controls operation of a network wherein at least one coded information stream is delivered to at least one user via at least one link exposed to variable operating conditions. The method includes the steps of: monitoring the operating conditions of the at least one link, and selectively transcoding the at least one coded information stream by selectively varying at least one transcoding parameter as a function of the operating conditions monitored. The monitoring operating conditions of the at least one link includes evaluating a set of cost functions related to an available bit rate and to complexity of said coded information stream and the selective variation of at least one transcoding parameter includes selecting among a plurality of transcoding levels associated to different values of quantization, resolution and frame rate.

Abstract: A spatial-type de-interlacing process to be applied to a digital image for obtaining a spatial reconstruction. Furthermore, to the digital image there are also applied one or more temporal-type motion compensation de-interlacing processes for obtaining one or more temporal reconstructions, and the spatial reconstruction and the one or more temporal reconstructions are sent to a decision module. The decision module applies a cost function to the spatial reconstruction and the temporal reconstructions and chooses from among the spatial reconstruction and the temporal reconstructions the one that minimizes the cost function. Preferential application is to display systems, in particular displays of a cathode-ray type, liquid-crystal type, and plasma type which use a mechanism of progressive scan.

Abstract: A process for encoding digital video signals organized in frames comprises the operations of dividing the frames into blocks starting from macroblocks subjected to motion-compensation and applying to the blocks a discrete cosine transform in such a way as to generate respective sets of coefficients. The sets of coefficients are then assembled by being organized into sets of vectors by a assembling module. Once the variance of the vectors has been detected, the vectors themselves are quantized on a number of available bits by a pyramid vector quantizer, associating to the vectors respective quantization pyramids having given sizes according to the variance detected and to the number of available bits. Finally, the vectors are encoded with respective codewords.

Abstract: A motion estimation process in video signals organized in successive frames divided into macroblocks that is carried out by the identification of motion vectors. In a first identification phase, starting from a current motion vector, a best motion vector predictor is identified, chosen from a set of candidates. The best predictor thus identified is then subjected to a second refining phase. The aforesaid set of candidates is identified by selecting vectors belonging to macroblocks close to the current vector within the current frame and the preceding frame. Preferably, the refining phase comprises the definition of a grid of n points centered on the central position to which the best motion vector points and the distance of the points of the grid from the center is defined as a function of the matching error typically consisting of an SAD function, defined in the first identification phase. Application to the IPB and APM operating modes of the H.263+ video standard is envisaged.

Abstract: A method of estimating the motion field of a digital picture sequence includes subdividing a current picture to examine in an integer number of macroblocks, for each macroblock of the current picture determining a search window centered on a macroblock of a preceding picture placed in the same position of the considered macroblock of the current picture, carrying out a motion estimation between the considered macroblock of the current picture and the macroblock most similar to it included in the window. At least a dimension of the search window is established as a function of the corresponding dimension of the search window used for the preceding picture, the estimated motion field of the preceding picture and certain threshold values.

Abstract: An RGB digital video signal destined to be displayed on a display such as a liquid crystal display (LCD) is converted from the RGB color space to the YUV color space. The signal converted into the YUV color space is subjected to at least a processing operation selected among a sub-sampling operation (24) and a data compression operation (26). The signal is then stored in a memory and the signal read from said memory (12) is then subjected to at least a return operation (28, 30) complementary to the aforesaid processing operation (24, 26). The signal subjected to the aforesaid return operation is lastly reconverted from the YUV color space to the RGB color space, thus being susceptible to be displayed on the display.

Abstract: A method of estimating the motion field of a digital picture sequence includes subdividing a current picture to examine in an integer number of macroblocks, for each macroblock of the current picture determining a search window centered on a macroblock of a preceding picture placed in the same position of the considered macroblock of the current picture, carrying out a motion estimation between the considered macroblock of the current picture and the macroblock most similar to it included in the window. At least a dimension of the search window is established as a function of the corresponding dimension of the search window used for the preceding picture, the estimated motion field of the preceding picture and certain threshold values.

Abstract: A process for format conversion of DCT macroblocks in an MPEG video bitstream that are divided into blocks, each of which includes a plurality of microblocks. In each DCT block, the significant frequencies are identified and preserved, isolating a corresponding microblock preferably consisting of the microblock on the top left of each block and setting to zero the coefficients of the remaining microblocks. On the microblock thus isolated there is performed an inverse discrete cosine transform, and the microblock thus obtained is merged with the homologous microblocks obtained from the other blocks comprised in a respective starting macroblock, so as to give rise to a merging block. The merging block thus obtained undergoes a discrete cosine transform so as to obtain a final block, which can be assembled into a macroblock with converted format.

Abstract: A method for coding video data according to the MPEG-2 standard is provided. Non-Intra fields are identified among Intra fields and various coding options exist for the non-Intra fields, including removal of temporal redundancy using a motion estimation algorithm and identification of predictor macroblocks for providing approximation according to a prediction mode selectable among respective predicting modes of the different types of non-Intra fields. The method includes calculating a discrete cosine transform (DCT) for blocks of data of the predictor macroblocks according to a frame mode of decomposition with the blocks being composed of lines of data belonging to even lines semifield and to odd lines semifield, or in a field mode of decomposition with the blocks being composed of lines of data belonging to the same semifield. The data resulting from the DCT carried out by blocks of data to be stored is quantized and coded.

Abstract: A process for encoding digital video signals organized in frames comprises the operations of dividing said frames into blocks starting from macroblocks subjected to motion-compensation and applying to said blocks a discrete cosine transform in such a way as to generate respective sets of coefficients. The said sets of coefficients are then assembled by being organized into sets of vectors by means of masking. Once the variance of the vectors has been detected, the vectors themselves are quantized on a number of available bits by means of a pyramid vector quantizer, associating to the vectors respective quantization pyramids having given sizes according to the variance detected and to the number of available bits. Finally, the vectors are encoded with respective codewords.

Abstract: A method for compressing encoding data of a sequence of pictures is based on a motion estimation among the successive images to remove the temporal redundancy from the data. The method recognizes a 3:2 pulldown conversion of a series of photograms of a filmed sequence in a sequence of TV frames. The TV frames have a number greater than the number of the photograms by duplicating certain pictures in a certain order. The redundancy due to such picture duplications is eliminated.