摘要:
The invention relates to a device for pre-processing video images intended to be coded in the MPEG 2 format. The MPEG 2 standard provides that, mode which exploits the spatial redundancy of the images. The images thus coded then define a succession of groups of images, a group of images being referred to as a GOP. The pre-processing device according to the invention comprises an image memory and an analysis circuit. The image memory makes it possible to store the various images contained in the forecast GOP of rank ok and ax of the first few images contained in the GOP of rank ok+l, ax being an integer greater than or equal to 1. The analysis circuit is linked to the image memory and makes it possible to perform measurements on the images contained therein. The knowledge about the images of the GOP of rank and about the first images of the forecast GOP of rank k+1 which is ascertained following the above mentioned measurements is then used for coding the GOP of rank k. The invention applies to systems for coding images according to the MPEG 2 standard.
摘要:
The invention relates to a process for coding digital data of a video sequence for its transmission and a variable bit rate. It is characterized in that the bit rate regulation in respect of the image at the instant n is performed as a function of a bit rate prediction in respect of the transmission channel for the instant n+&tgr;, &tgr; being a constant time between the instant of storage of an image in the buffer of the coder and the instant of output of this image from the buffer of the decoder.
摘要:
A method and a device for coding and decoding a sequence of images or pictures is disclosed. One exemplary embodiment disclosed codes by dividing each picture into blocks of picture elements. Each element of a block being represented by a digital value. Two types of coding are utilized in order to reduce the amount of data; inter-coding, which takes into account a corresponding block in a previous picture and intra coding, which is independent from a previous picture. Blocks being thus coded so that a further reduction of data is obtained by transmitting high spatial frequencies with less weight than low spatial frequencies. This is accomplished with the use of weighting coefficients. Weighting coefficients are variable as a function of the quantity of information to be transmitted.
摘要:
The locking device locks the valve control lever in both its closed or open positions. It consists of a male part and a female part. The male part includes a lengthwise cavity, for flatly and freely receiving the valve lever, and a U-shape extension, transversely extending from one end of the male part main body. The female part defines a channel for sliding engagement by the interconnected male part and valve lever, to interlock same. A padlock interlocks the male and female parts by engaging registering ears thereof.
摘要:
A variable length encoding method for encoding a finite or infinite series of values corresponding to a random variable whose distribution monotonically decreases on either side of the mean value in which the encoding tree has a regular structure which is defined by an arithmetic and logic device. In order to encode each value E, a first binary word, including only bits having a same value and whose number of bits B is an increasing function of the value to the encoded E, is determined. The number of bits B is computed according to a predetermined arithmetic and logic function B(E). The method also involves determining a second binary word having a value to be encoded, in the set of values to be encoded arranged in order of decreasing probability, and whose number of bits B' is derived from the function B(E) and from the number of bits B in the first binary word. A code word is formed by combining the first and second binary words thus determined.
摘要:
A method and a device for coding and decoding a sequence of images or pictures is disclosed. One exemplary embodiment disclosed codes by dividing each picture into blocks of picture elements. Each element of a block being represented by a digital value. Two types of coding are utilized in order to reduce the amount of data; inter-coding, which takes into account a corresponding block in a previous picture and intra coding, which is independent from a previous picture. Blocks being thus coded so that a further reduction of data is obtained by transmitting high spatial frequencies with less weight than low spatial frequencies. This is accomplished with the use of weighting coefficients. Weighting coefficients are variable as a function of the quantity of information to be transmitted.
摘要:
Synchronization for a device receiving an input sequence of variable length rasters even in the presence of transmission errors. Each variable length raster is preceded by an N times identically repeated prefix, this prefix is composed of a fixed binary pattern separator and a parameter word describing the variable length raster to follow. Upon identifying a fixed binary pattern separator, even in the presence of transmission errors, the synchronization device outputs asynchronization signal signaling that a parameter word is to follow. The parameter word input is then subjected to transmission error elimination and output to the receiving device. Thus the receiving device is able to properly input the incoming variable length raster based on a accurate parameter word.
摘要:
A method and a device for coding and decoding a sequence of images or pictures is disclosed. One exemplary embodiment disclosed codes by dividing each picture into blocks of picture elements. Each element of a block being represented by a digital value. Two types of coding are utilized in order to reduce the amount of data; inter-coding, which takes into account a corresponding block in a previous picture and intra coding, which is independent from a previous picture. Blocks being thus coded so that a further reduction of data is obtained by transmitting high spatial frequencies with less weight than low spatial frequencies. This is accomplished with the use of weighting coefficients. Weighting coefficients are variable as a function of the quantity of information to be transmitted.
摘要:
The present invention relates to a method and apparatus of encoding and decoding blocks of data words. Each block has a fixed number of data words with a maximum of nbits, and a position of a data word within a block is diagonally identified by a series of absolute addresses having consecutive values. In the encoding of the data words of a block, the data words are classified into groups based on their most significant non-zero bit. Then the corresponding absolute address of each classified data word is encoded based on the absolute address of a previously encoded data word in the same class as the current classified data word and the number of data words encoded in classes less than the current classified data word since the previous encoding of a data word in the class of the current classified data word. Each data word with its ith and greater bits omitted is then transmitted along with the encoded absolute address. The encoded data words are decoded by determining the class of each encoded data word and storing, class by class, the encoded data words and their corresponding encoded addresses. The ith and greater bits of each encoded data words are reconstituted, and the encoded absolute addresses of each data word are then reconstituted into absolute addresses to reconstitute a block of data words.
摘要:
The synchronization method, consists in transmitting, in addition to the data:inter-block separators, for separating the data corresponding to separate blocks, each inter-block separator comprising: a fixed radical, a first binary word representing the rank of a block of picture elements associated with this separator, and a second binary word representing the sum of this rank and of the number of events which are encoded by the data corresponding to the block associated with this separator;picture separators, for separating the data corresponding to successive pictures, each picture separator being repeated several times and comprising a fixed radical followed by a binary word indicating the rank of the separator in the repetitions;synchronization patterns at the picture line frequency and synchronization patterns at the picture frequency, transmitted while interrupting the transmission of the data and of the separators.application to the transmission of digital video pictures on an asynchronous channel.