Abstract: A transcoder and a method of transcoding which reduces computational requirements without picture deterioration. A mode decision unit decides a mode of a scaled output macro block based on an area of the scaled macro block overlapped with a non-scaled macro block of a reference frame and a mode of the overlapped macro block. A motion vector decision unit decides a reference motion vector of the output macro block based on a motion vector with respect to the overlapped macro blocks. A picture quality preference mode selection unit receives a user picture quality preference command. A motion vector compensation unit compensates the motion vector of the output macro block based on the decided reference motion vector and the picture quality preference command.

Abstract: An apparatus and method for variable length coding are provided. The apparatus for variable length coding includes a central processing unit which has a software module programmed in advance for variable length coding in a predetermined method, performs variable length coding of input symbol data by using the software module, and generates variable length code information. The apparatus further includes a bitstream processor which is a separate processor receiving the variable length code information from the central processing unit and generating a bitstream. According to the apparatus and method, modification or addition of a VLC table can be more easily performed through downloading software such that new video data coding standards can be easily supported. Also, by implementing the bitstream processor as a separate dedicated processor and thus implementing variable length coding as a software module, load to the central processing unit is reduced and high speed processing is enabled.

Abstract: A video decoding method and a video decoding apparatus capable of reducing a memory bandwidth in an intensity compensation process are provided. The video decoding apparatus includes: a bit stream parsing unit which parses an input bit stream, extracts intensity compensation data of a picture to be decoded; a decoding unit which decodes the picture to be decoded; and a memory which stores the decoded picture, wherein the decoding unit comprises a motion compensation unit which reads a motion compensation picture, that is referred by the picture to be decoded for motion compensation, from the memory in block unit of a predetermined size, performs intensity compensation with respect to a motion compensation block of the motion compensation block using the intensity compensation data, and performs the motion compensation with respect to the intensity-compensated motion compensation block.

Abstract: A video codec system, a data processing method for processing data between the system and an external host system, and an encoding/decoding control method in the system are provided. The video codec system includes an encoder buffer; a decoder buffer; a task status register for writing the task statuses of the encoder, decoder, encoder buffer and decoder buffer; a command identification register for writing a command to be executed by the encoder and decoder; and an interface and control manager for parsing the command sent from the host system, writing the command in the command identification register, checking each task through the task status register, and then controlling the encoder and decoder through the command identification register. Therefore, the video codec system enhances the performance and reliability of the video code and makes the control of the encoding and decoding tasks easier.

Abstract: A variable length coding apparatus and a variable length coding method including a prepacking unit which processes two data items, each of which is formed with a code value and a code length and is received from a variable length code generator at each clock cycle, into one data item and outputs the processed data item to perform bitstream packing. With this structure, a variable length coding apparatus operating at a high speed without idling can be implemented.

Abstract: Provided is a method and apparatus for re-concealing an error included in a decoded image. The method includes determining whether a first reference block in a first reference frame, which is used for motion compensation of a current block, includes an error concealed area, and performing error re-concealment on the error concealed area included in the current block if the first reference block includes the error concealed area.

Abstract: A variable length coding method and apparatus is provided. The variable length coding method includes the steps of (a) selecting predetermined macroblocks from among the previous macroblocks of a macroblock to be coded in a current frame, (b) analyzing the occurrence statistics of symbols with respect to the selected macroblocks, (c) resetting a mapping relationship based on the analyzed occurrence statistics of symbols, and (d) variable length coding a current macroblock based on the reset mapping relationship. The variable length coding method dynamically varies the mapping relationship between symbols and bit patterns based on the occurrence statistics of the symbols, thereby reducing the amount of bits generated when coding images of the same picture quality.

Abstract: A variable length coding apparatus and a variable length coding method including a prepacking unit which processes two data items, each of which is formed with a code value and a code length and is received from a variable length code generator at each clock cycle, into one data item and outputs the processed data item to perform bitstream packing. With this structure, a variable length coding apparatus operating at a high speed without idling can be implemented.

Abstract: An apparatus and method for variable length coding are provided. The apparatus for variable length coding includes a central processing unit which has a software module programmed in advance for variable length coding in a predetermined method, performs variable length coding of input symbol data by using the software module, and generates variable length code information. The apparatus further includes a bitstream processor which is a separate processor receiving the variable length code information from the central processing unit and generating a bitstream. According to the apparatus and method, modification or addition of a VLC table can be more easily performed through downloading software such that new video data coding standards can be easily supported. Also, by implementing the bitstream processor as a separate dedicated processor and thus implementing variable length coding as a software module, load to the central processing unit is reduced and high speed processing is enabled.

Abstract: A transcoding apparatus and method, and target bit-allocation and picture complexity estimation units and methods used for the same are provided. The transcoding apparatus includes: a video decoding unit which receives a compressed bitstream and performs decoding thereof to output decoded pictures; a complexity estimation unit which estimates complexity of a current picture among the decoded pictures to encode the current picture; a target bit-allocation unit which performs desired bit-allocation using the complexity information of the current picture; a bit-rate control unit which controls bit-rate using bit-allocation information and state information from memory, which outputs an encoded bitstream; and a video encoding unit which encodes the decoded pictures on the basis of the bit-allocation and state information of the bit-rate control unit. Therefore, an effect exists for transcoding that improves image quality.

Abstract: A variable length coding method and apparatus is provided. The variable length coding method includes the steps of analyzing the occurrence statistics of symbols with respect to previous frames, generating a mapping table for variably mapping input symbols to bit patterns based on the analyzed occurrence statistics of the input symbols, resetting the mapping relationship between symbols and bit patterns based on the generated mapping table, and variable length coding a current frame based on the reset mapping relationship. The variable length coding method efficiently reduces the number of bits generated by dynamically varying the mapping between input symbols and bit patterns depending on the occurrence statistics of the input symbols.

Abstract: A transcoder and a method of transcoding which reduces computational requirements without picture deterioration. A mode decision unit decides a mode of a scaled output macro block based on an area of the scaled macro block overlapped with a non-scaled macro block of a reference frame and a mode of the overlapped macro block. A motion vector decision unit decides a reference motion vector of the output macro block based on a motion vector with respect to the overlapped macro blocks. A picture quality preference mode selection unit receives a user picture quality preference command. A motion vector compensation unit compensates the motion vector of the output macro block based on the decided reference motion vector and the picture quality preference command.

Abstract: A video codec system, a data processing method for processing data between the system and an external host system, and an encoding/decoding control method in the system are provided. The video codec system includes an encoder buffer; a decoder buffer; a task status register for writing the task statuses of the encoder, decoder, encoder buffer and decoder buffer; a command identification register for writing a command to be executed by the encoder and decoder; and an interface and control manager for parsing the command sent from the host system, writing the command in the command identification register, checking each task through the task status register, and then controlling the encoder and decoder through the command identification register. Therefore, the video codec system enhances the performance and reliability of the video code and makes the control of the encoding and decoding tasks easier.

Abstract: A multi-bit data latch includes a gated input buffer having a buffer input terminal, a buffer output terminal, and a buffer control terminal. The gated input buffer provides an output signal at the buffer output terminal responsive to an input signal applied to the buffer input terminal subject to a buffer control signal at the buffer control terminal. A first latch circuit has a first latch output terminal and a first latch input terminal, and a second latch circuit has a second latch output terminal and a second latch input terminal. A first switching circuit is operative to connect and disconnect the first latch input terminal to a reference voltage source responsive to an output signal at the buffer output terminal and to a first latch control signal. A second switching circuit is operative to connect and disconnect the second latch input terminal to the reference voltage source responsive to an output signal at the buffer output terminal and to a second latch control signal.

Abstract: A method and a device for wet desulfurization of flue gas to remove a sulfur dioxide(SO.sub.2) contained in flue gas discharged from thermal power stations and boilers are disclosed. In the method the device with a gas layered sieve plate for wet desulfurization of flue gas, an absorbing liquid improves reacting conditions by effecting it own circulation without using additional power due to the structural characteristics possessed by the device and flue gas is treated very satisfactorily thanks to high gas-liquid contact efficiency. In order to minimize power consumption and the size of the device but promote desulfurization to an unusual degree, an absorber is divided into an upper froth layer and a lower liquid layer by a single-stage gas dispersing plate with a large number of gas ejection holes bored therein.