Abstract: An apparatus and method for concealing error in moving picture decompression system is disclosed. The present invention predicts motion vectors of a damaged block from motion information of a previous block and an upper block adjacent to the damaged block when an error occurs, and compensate the damaged block. Therefore, the error concealment apparatus and method compensates for and maintains good picture quality at the receiving terminal against errors occurring in a channel.

Abstract: An MPEG-2 video decoding system simultaneously decodes two or more HD-class MPEG sequences using a single video decoder, and reduces memory capacity and bandwidth. According to the video decoding system, a buffer size is reduced by efficiently sharing a video buffer, and a great reduction of a gate size can be obtained by integrating a VLD unit and a picture controller, and by integrating a motion compensation unit and a memory interface, respectively. Also, two or more HD-class MPEG sequences are displayed in the form of a PIP or a split screen. In the case of the PIP display, a DTV main picture is displayed in a non-compression mode, and a DTV sub-picture is displayed in a ¼-compression mode. In the case of the split-screen display, the DTV main picture and the DTV sub-picture are displayed in a ½-compression mode.

Abstract: An MPEG video decoding system with a PVR (Personal Video Recorder) function is disclosed. By applying the PVR function to an MPEG-2 decoder chip, which is the standard recommendation of the digital video transmission field, diverse high-performance PVR services such as video storage and search using an HDD application in the video decoder chip can be used, and two HD-class displays can simultaneously be supported. Also, the features of the video TS bitstream stored through the video decoding chip having a proposed PVR engine can be extracted in real time, and the playback or trick play of the stored video contents can be diversely and easily performed. According to the PVR-support video decoding system, an improved storage and search function of a video bitstream, and diverse video services can be provided, and the added value of the digital video recorder can be heightened.

Abstract: A moving picture compression/decompression system utilizes a method for concealing errors in a received picture. A macro block, lost due to an error, is compensated using either a temporal or spatial prediction method, depending upon the type of frame and the characteristics of the picture. Thus, the displayed picture quality can be significantly improved.

Abstract: A method for concealing an error in a motion picture compression/restoration device is disclosed. In the present invention, a damaged macro block is restored by predicting an optimal motion vector V*x and V*y from all possible motion vectors Vx and Vy within a fixed search range of a previous frame by application of a weighted value function. Accordingly, the damaged macro block is replaced with a macro block from a previous frame obtained by the predicted motion vector. The present invention not only improves the visual effects of a restored image, but also reduces the amount of necessary calculation, allowing realtime compensation.

Abstract: A video decoding system and a memory interface thereof are disclosed, in which Y, Cb and Cr data of one macro block is rearranged to be simultaneously stored in an external memory and to be simultaneously read from the external memory, when storing video decoded data in the external memory, and outputting the stored data for motion compensation with a data bus of 96 bits, thereby decreasing an entire bandwidth of a video decoder and a local processing time.

Abstract: An MPEG-2 video decoding system is disclosed, which is applied to a digital TV or a digital video conference. In the present invention, ‘I’ or ‘P’ as a reference frame is reduced in a horizontal direction at 1/2, and then is stored in an external memory. Meanwhile, in a case of ‘B’ picture which is not used as a reference frame, ‘B’ picture is reduced in both horizontal and vertical directions by 1/2, so that ‘B’ picture is reduced at 3/4, and then is stored in the external memory. Accordingly, it is possible to reduce memory at 50% to 62.5% and to maintain a good picture quality in the present invention. Also, field information of the vertical direction is maintained, thereby decreasing drift errors during decoding MPEG video.

Abstract: An apparatus and method of transcoding a video snap image is disclosed. The apparatus includes a video decoder for performing a variable length decoding (VLD), inverse discrete cosine transform (IDCT), and inverse quantization with respect to an input bit stream to display the decoded bit stream, a DC extraction section for extracting DC components from discrete cosine transform (DCT) coefficients of variable-length-decoded macro blocks, an adder for averaging the extracted DC components, a differential pulse code modulation (DPCM) section for obtaining and outputting a difference value between the DC component averaged by the adder or the DC component outputted from the DC extraction section and a DC component of a previous macro block, a Huffman encoding section for Huffman-encoding the difference value outputted from the DPCM section, and a storage device for storing a Huffman-encoded snap image and the video bit stream.

Abstract: An error concealment method of a motion video decompression system is disclosed. The present invention uses motion vector estimation to recover video signals, with errors generated by a transmission state, nearly to the original video. Particularly, the present method includes estimating motion information of a lost video, and restoring the lost video from a video adjacent to the lost video by using the estimated motion information.

Abstract: Disclosed is a video transcoding apparatus converting a specific bit rate of an MPEG (moving pictures experts group) bit stream into a different rate thereof for transportation. The present invention includes a video pre-processing unit having a predetermined matrix structure and down-sampling a macro block decoded by the video decoder by transforming the macro block into a corresponding picture structure to the compressed video bit stream, a transcoding parameter control unit detecting information about a picture from a previous bit stream variable-length-decoded by the video decoder and setting up an encoding mode for a transcoding in accordance with the detected information, etc. Therefore, the present invention does not need the motion estimation unit of encoder and reduce the complexity of the bit allocation unit. When changing HD-rated MPEG sequence over 10 Mbps into NTSC-rated MPEG sequence below 6 Mbps, the present invention reduces calculation time and complexity of hardware.

Abstract: A method and an apparatus of transcoding image data in a digital TV system are disclosed. The method and apparatus of the present invention performs global and local motion compensation processes while converting the particular data bit rate of input image data to a different data bit rate. As a result, the quality of the image can be greatly improved compared to other existing techniques. When there is no global motion detected in an image frame, the local motion compensation is performed based on new local motion vectors estimated or on the previous local motion information.

Abstract: The present invention relates to a video decoder with a down conversion function, and a method for decoding a video signal.

Abstract: A memory reducing device in an apparatus for receiving moving pictures is applied to the fields such as a digital television receiver, a digital video conference system and the like. The memory reducing device enables to reduce an external memory of an MPEG-2 video decoding chip and obtain standard deviations by predicting the current pixel using a pixel located at the highly-related direction which is determined by having the deviation estimating part measure the relation between the horizontal or vertical direction of the pixels adjacent there between and to be currently encoded. Moreover, the memory reducing device enables to increase a compression ratio as well as provide clear distinction of high definition by reducing the difference less than the bit precision of the current pixel by means of predicting the current pixel by selecting the pixel located at the highly-related direction with the above same method and performing quantization with the prediction.

Abstract: An apparatus for receiving digital motion pictures for down-conversion of interlaced scanning sequence in DTVs or application fields of digital picture meeting systems is disclosed, in which received DCT coded blocks are down-sampled as they are if the blocks are field DCT coded blocks, or converted to the field DCT coded blocks to carry out the down-sampling and stored in the memory for the motion picture if the blocks are frame DCT coded blocks, or the field DCT coded blocks and the frame DCT coded blocks are stored after down-conversion into pictures having fixed top field pixels for the motion prediction compensation, so that 75% memory reduction effect may be obtained by a video decoder having a down converter for the interlaced scanning sequence of the HD grade, and a screen of the SD grade with high screen quality may be obtained in the display devices for the various PIPs or the low resolution display.