Abstract: A loop-filtering method for reducing quantization effect generated when an image data is encoded and decoded, and an apparatus therefor. The loop-filtering method includes the steps of extracting a flag indicating whether the image data requires loop-filtering using the distribution of inverse quantized coefficients (IQCs) of an inverse quantized image data and a motion vector indicating the difference between the previous frame and the current frame. The image data corresponding to the flag is then filtered by a predetermined method if the extracted flag indicates a need for the loop-filtering. Using the flags and an adaptive filter reduces the quantization effect and is useful to reduce the amount of computation required for the filtering. Also, the filtering can be performed through parallel processing without multiplication and division, so that the complexity of hardware can be reduced.

Abstract: A signal adaptive filtering method for reducing blocking effect and ringing noise. a signal adaptive filter, and a computer readable medium. The signal adaptive filtering method capable of reducing blocking effect and ringing noise of image data when a frame is composed of blocks of a predetermined size includes the steps of: (a) generating blocking information for reducing the blocking effect and ringing information for reducing the ringing noise, from coefficients of predetermined pixels of the upper and left boundary regions of the data block when a frame obtained by deconstructing a bitstream image data for inverse quantization is an intraframe; and (b) adaptively filtering the image data passed through inverse quantization and inverse discrete cosine transform according to the generated blocking information and ringing information. Therefore, the blocking effect and ringing noise can be eliminated from the image restored from the block-based image, thereby enhancing the image restored from compression.

Abstract: A data transmitter transmitting a data packet containing identifier information comprising a kind of data, a sequence of data, and/or a packet generating sequence. A receiver extracting a packet number and the identifier information for an error-receipt occurring data packet based upon the identifier information recorded in a header of the packet, generating retransmission control information, such as retransmission times and priority, based on the extracted packet number and the identifier information and transmitting the retransmission control information to the transmitter of the packet. The retransmitting the error-occurring data packet according to the received retransmission control information. The number of retransmissions and the retransmission priority can be varied according to characteristics of the transmitted data, so that retransmissions is suitable for the characteristics of the data and to more stably receive the data that is more influential to the restoration of the data.

Abstract: A signal adaptive filtering method for reducing blocking effect and ringing noise, a signal adaptive filter, and a computer readable medium. The signal adaptive filtering method capable of reducing blocking effect and ringing noise of image data when a frame is composed of blocks of a predetermined size includes the steps of: (a) generating blocking information for reducing the blocking effect and ringing information for reducing the ringing noise, from coefficients of predetermined pixels of the upper and left boundary regions of the data block when a frame obtained by deconstructing a bitstream image data for inverse quantization is an intraframe; and (b) adaptively filtering the image data passed through inverse quantization and inverse discrete cosine transform according to the generated blocking information and ringing information. Therefore, the blocking effect and ringing noise can be eliminated from the image restored from the block-based image, thereby enhancing the image restored from compression.

Abstract: An image data providing system and a method thereof. A group of pictures and detailed information for a scene are stored in a first storing portion, while a lookup table, including location information and a frame number of an image of a certain format within the group of pictures, is stored in a second storing portion. When receiving from user information about a reproducing point of a request image, a data providing portion searches the lookup table for a location of a file about the image of a certain format according to information about the time, i.e., the reproducing point. The data providing portion extracts image data from the first storing portion based on the searched location of the file and provides the user with the extracted image data. Based on the location information and the frame number of the intra picture that is written in advance according to the time, the image data corresponding to the user requested location is rapidly extracted and provided to the user.

Abstract: An image data post-processing method for reducing quantization effect induced when image data compressed based on a block is decoded, and an apparatus therefor. The image data post-processing method includes the steps of: (a) detecting semaphore representing whether or not post-processing is required, using distribution of inverse quantization coefficients of inverse-quantized image data and a motion vector representing the difference between the blocks of a previous video object plane (VOP) and blocks of a current VOP; and (b) filtering the decoded image data corresponding to the semaphore by a predetermined method, if it is determined by checking the detected semaphore that post-processing is required. Therefore, the quantization effect can be reduced by using the semaphore and an adaptive filter, and the amount of computation for filtering is also reduced. Also, the complexity of the hardware is reduced by a parallel process without multiplication and division.

Abstract: A wireless packetization apparatus for transmitting and/or receiving multimedia data including video data in a radio transmitting/receiving system, and a method thereof are provided. According to the present invention, error resilience can be increased by adding error protection codes to one portion and a plurality of portions of multimedia-related header information, respectively, when multimedia data such as video data requiring real time or low delay are transmitted and received in a wireless environment, and a packet drop rate can thereby be reduced. Also, information can be more precise recovered by inserting length identifier and length information on an information region into the header.

Abstract: A wireless packetization apparatus for transmitting/receiving multimedia data including video data in a radio transmitting/receiving system, and a method thereof are provided. According to the present invention, error resilience can be increased by adding an error protection code and a corruption indication flag to header information on a radio link protocol (RLP) layer when multimedia data such as video data requiring real time or low delay is transmitted and received in a wireless environment, and a packet drop rate can be thereby reduced.

Abstract: An apparatus and method of transceiving a bit stream, by which a video bit stream is stably transmitted by the effective use of two logic channels when communication is established by the two logic channels during transmission of the video bit stream in a communication network, is provided. In this method, a source is encoded into a bit stream using a predetermined type of coding. Then, the encoded bit stream is transmitted to each communication protocol layer, while the header of each communication protocol layer is added to a payload. The header is transmitted separately from the bit stream.

Abstract: A signal adaptive filtering method is disclosed for reducing a blocking effect and ringing noise of an image data. A gradient of the image data is calculated for each pixel of the image data. Then, the gradient data of each pixel is compared with a global threshold value (Tg) which is determined based on a predetermined quantization step size (Q), and global edge map information of the pixel is generated. Meanwhile, the gradient data of each pixel is compared with a local threshold value (Tn) determined for each block having a predetermined size, and local edge map information of the pixel is generated. An OR operation is performed with respect to the global edge map information and the local edge map information to generate binary edge map information. Then, a predetermined sized filter window is applied to determine whether edges are present in the binary edge map information within the filter window.

Abstract: A gradient is calculated at each pixel of the image data to be filtered using a one-dimensional horizontal gradient operator of 1×2 size and a one-dimensional vertical gradient operator of 2×1 size, each of the gradient operators having a weighted value (1,−1). The absolute value of the calculated gradient is then compared with a predetermined threshold value to generate a binary value. This gradient calculation and comparison with a threshold is repeated for pixel blocks having a predetermined size to generate a binary edge map with respect to a whole block. A filter window of a predetermined size is then applied to the generated binary edge map to determine whether edges are present in the filter window. If no edges are present in the filter window, then the pixel values of the corresponding filter window pixel are filtered pixel-by-pixel by using a predetermined first set of weighted values to generate a new pixel value.

Abstract: A one-dimensional signal adaptive filtering method and a one-dimensional signal adaptive filter.

Abstract: A loop filtering method and a loop filter therefor are provided.

Abstract: An adaptive signal filtering method is provided to reduce blocking effects caused by decompression the block-based compressed images.

Abstract: A signal adaptive loop filter reduces blocking effects and ringing noise of motion-compensated image data. In the loop filter, binary edge map information on which global thresholding and local thresholding with respect to the motion-compensated image are reflected, is used to judge whether the binary edge map information within a predetermined size of the filter window is either a homogeneous or an edge area. If it is judged as a homogeneous area, predetermined first weight factors corresponding thereto are used for generating a filtered pixel value for the corresponding filter window. While, in the case that it is judged as an edge area, predetermined second weight factors are varied according to the binary edge map information corresponding to pixels, and the filter window having the varied second weight factors is used for generating the filtered pixel value corresponding to respective pixels.