摘要:
In a transmitter, a standard stream of encoded multi-media data and uniform error correction data is transmitted through a first channel. The uniform error correction data provides substantially the same error correction for all portions of the encoded multimedia data. Simultaneously, additional unequal error correction data is generated for critical portions of the standard stream and not for other portions of the standard stream, and the additional error correct data is transmitted through a second channel. In a receiver, the additional error correct data is used to error correct just the critical portions of the standard stream, and then the uniform error correction data is used to error correct all the portions of the encoded multimedia data of the standard stream.
摘要:
A video signal is coded by generating, at a transmitter, a difference signal (at 2) representing the differences between a picture to be transmitted and a predicted picture based on a stored locally decoded picture. This is decoded to generate a fresh locally decoded picture. The transmitter also generates a check signal, such as a CRC, as a function of the locally decoded picture. The receiver decodes the difference signal to create a decoded picture. It compares the decoded picture with the check signal, and generates an error signal if the two do not tally.
摘要:
An error detecting method and apparatus may be provided for a moving image transmitting system. An error detection code may be generated for each data block of a frame. The generated error detection code may be inserted into a byte alignment code of the data block. The frame may then be transmitted from a transmitting side to a receiving side. A byte alignment code may be extracted from each data block after the frame is received at the receiving side. Errors may be detected based on the extracted code. The method may enable a moving image encoder to be stably operated and allow improvement of the picture quality. Also, the method may allow the byte alignment code, which has been regarded as meaningless information, to be associated with a channel code so as to enhance error detection efficiency.
摘要:
In a digital satellite television system in which a television receives its signal via receiver/decoder, such as a set top box, interactive applications can be downloaded and run on the receiver/decoder. The application code is arranged as modules, and the downloading of modules is preceded by searching a directory module within a specified local address. The modules are signed and the directory module is signed and encrypted so that a single encryption applies to all of the modules making up the application. Multiple public encryption keys are stored in ROM in the receiver/decoder, so that applications can be created by different sources, without the sources needing to know each other's private encryption keys. A facility is provided to enable an encryption key to be temporarily stored in RAM in the receiver/decoder, so that a manufacturer of the receiver/decoder can check its functionality. A signature of the directory may be hidden at a variable position in a block of dummy data in the directory module. An application to be downloaded may be checked against an application validation bitmap stored in the receiver/decoder.
摘要:
A data encoding system includes a modifier, an encoder, and a feedback. The modifier receives a first data stream and modifies the first data stream so as to provide a second data stream. The encoder encodes the second data stream in order to provide an output. At least a portion of the output has predetermined symbol values. A feedback from the encoder to the modifier provides encoder states to the modifier. The modifier modifies the first data stream based on the encoder states so as to facilitate the encoder in providing the portion of the output having the predetermined symbol values. A receiver receives a signal based on the output and decodes the signal.
摘要:
An active stream format is defined and adopted for a logical structure that encapsulates multiple data streams. The data streams may be of different media. The data of the data streams is partitioned into packets that are suitable for transmission over a transport medium. The packets may include error correcting information. The packets may also include clock licenses for dictating the advancement of a clock when the data streams are rendered. The format of ASF facilitates flexibility and choice of packet size and in specifying maximum bit rate at which data may be rendered. Error concealment strategies may be employed in the packetization of data to distribute portions of samples to multiple packets. Property information may be replicated and stored in separate packets to enhance its error tolerance. The format facilitates dynamic definition of media types and the packetization of data in such dynamically defined data types within the format.
摘要:
In a coding system wherein an error correction/detect-ion coding is combined with a synchronization recovering technique using a synchronization code, the problems of a pseudo synchronization and a step out due to error detect-ion are solved. There is provided a coding part for coding an input multiplexed code string to an error correcting/detecting code comprising an information bit and a check bit, and code string assembling part for inserting a synchronization code into any one of a plurality of periodically predetermined synchronization code inserting positions in a code string, for arranging the information bit at an optional position in the code string, and for arranging the check bit at a position other than the synchronization code inserting positions in the code string to assemble an output code string.
摘要:
Video data recording apparatus for recording video data representing successive video images comprises a tape recording system in which video data is recorded on successive tracks of a tape recording medium, video data representing each image occupying a predetermined plurality (n) of successive tracks; and a data shuffler for shuffling the video data according to a shuffle pattern, for recording on the successive tracks of the tape recording medium, so that video data representing each of a plurality of sub-areas of an image is recorded in respective parts on all n tracks occupied by that image, at respective track positions so that corresponding positions along pairs of adjacent tracks are occupied by data representing different ones of the plurality of sub-areas.
摘要:
A data communications protocol for single path media having low data error rate requires the generation of a data packet with a start code field having a predetermined pattern, a byte count field for defining a data field having a maximum predetermined length in bytes, a data payload field having a byte count according to the value of the byte count field and a cyclic redundancy check field of predetermined length. The value of the byte count field may be fixed, may be changed from packet to packet or may be changed upon initialization. The described data communications protocol permits utilization with data types varying from high definition television to alarm reporting applications. Moreover, the data rate may be varied by varying an idle time signal duration up to a maximum (when the idle time signal duration is reduced to zero). According to one exemplary embodiment for plastic fiber optic media, MPEG2 transport stream packets may be transmitted at 54 MBaud over distances of 20 meters or even more with other media.
摘要:
An image processing apparatus comprises a receiving device for receiving encoded image data which is encoded by using orthogonal transform in a predetermined block unit, an error detecting device for detecting a transmission error of the encoded image data, a correcting device for correcting the transmission error in the predetermined block unit, and a decoding device for decoding the encoded image data and outputting image data for reproducing an image. The image processing apparatus satisfactorily controls the amount of compressed data and prevents a deterioration of image quality even if any error occurs on a transmission path, thereby reproducing good image quality.