摘要:
According to a first aspect of the invention, digital image data are recorded in the form of compressed codewords with check information and flags. The flags indicate codewords containing uncorrected errors. Each time the data are copied, error detection and correction are performed and the flags are updated to indicate any new uncorrectable errors that are detected. The flags can be used for error concealment, to avoid error miscorrection, and to permit the check information to be regenerated each time the data are copied. According to a second aspect of the invention, when image data are copied, the same check information is used to perform error detection and correction twice. Flags identifying uncorrected errors can be transferred from the first error-detecting-and-correcting process to the second.
摘要:
A coding method and apparatus is for coding a digital video signal of interlaced type. Three-dimensional (horizontal, vertical and temporal directions) blocks are constructed for each of a plurality of picture elements, orthogonal transform is performed to each of the three-dimensional blocks and coefficients are coded. Coefficients non-effected by a pseudo-moving part are weighted with a low rate, and coefficients effected by a pseudo-moving part are weighted with high rate. After the vertical positions of picture elements of odd-number fields and those of even-number fields are coincided with each other by an intra-field picture element operation, the digital video signal is formatted and three-dimensional orthogonal transform is performed.
摘要:
In a high-efficiency encoder which performs motion-compensation prediction, an intra-field is set every n fields. The presence of a scene change is detected. When a scene change occurs, a reference picture of motion-compensation prediction is switched, or the field immediately after the scene change is set as an intra-field.
摘要:
A pulse code modulation (PCM) recording and reproducing apparatus for recording analog signals from N channels which are sampled at a predetermined sampling frequency and converted into samples of a variable number of bits each. The samples of PCM data are assembled into a frame consisting of a specific number of samples and the frames are assembled into a number of blocks of PCM data comprising a specific number of tracks. The number of bits per frame is set to a value equal to the least common multiple of all values of bit quantization numbers which the samples may have such that digital signal sources of varying bit quantization formats may be accomodated by the recording apparatus utilizing a simplified structure.
摘要:
A reproduced PCM signal in the form of continuous frames is subjected to a code check after the separation of its frame synchronizing signals and then stored in a memory. If more than two consecutive frames are determined to include code errors resulting from a spliced portion of the associated PCM magnetic tape than those frames are prevented from being written into the memory but the latter is continuously read out by skipping the lost data and reading other data stored in the memory. Also the amount of data stored in the memory is sensed and maintained at a predetermined constant magnitude by controlling the speed of travel of the tape.
摘要:
A PCM signal is divided into groups each including S sampled values represented by B bits respectively and R code error check bits are added to each group to form one frame. The frames are successively and repeatedly recorded in N tracks on a recording medium with frame synchronizing signals each including M bits, the signals alternating the frame in each track. The frame synchronizing signal in each track delays the next track by m bits. The m satisfiesm = (B .times. S + R - m')/(N - 1) and M = m - m'Where m' designates the number of bits fully filling a temporal spacing between the end of the frame synchronizing signal in each track and the beginning of the next track.
摘要:
This repair device includes a casing, a slide shaft slidably arranged with respect to the casing, a turn table rotatably arranged with respect to the slide shaft, a cutting mechanism installed on the turn table and including a cutting tool, and an advancing and retracting mechanism that displaces a radius of rotation of the cutting mechanism with respect to rotations of the turn table forward and backward. In a state where the casing is centered and positioned with respect to the pipe, the turn table is rotationally displaced while the slide shaft slides in an axial direction, and the advancing and retracting mechanism displaces the cutting mechanism forward and backward. Accordingly, the cutting tool helically turns along an inner peripheral shape of the pipe to cut an inner periphery of the pipe.
摘要:
In a high-efficiency encoder which performs motion-compensation prediction, an intra-field is set every n fields. The presence of a scene change is detected. When a scene change occurs, a reference picture of motion-compensation prediction is switched, or the field immediately after the scene change is set as an intra-field.
摘要:
In a high-efficiency encoder which performs motion-compensation prediction, an intra-field is set every n fields. The presence of a scene change is detected. When a scene change occurs, a reference picture of motion-compensation prediction is switched, or the field immediately after the scene change is set as an intra-field.
摘要:
A digital video/audio recording and reproducing apparatus comprising a video signal high-efficiency encoder having a variable reduction rate, an audio signal high-efficiency encoder having a variable reduction rate, and a controller for controlling the reduction rates in both of the high-efficiency encoders. The reduction rates in both of the high-efficiency encoders are controlled in such a manner that the sum of the information amount of the video signal and that of the audio signal, after high-efficiency encoding, is maintained constant. When recording multi-channel audio signals, the reduction rates in both of the high-efficiency encoders are controlled according to the number of audio signal channels to be recorded. The high frequency components of the high-efficiency encoded video and audio signals are recorded at the end portions of recording tracks on a magnetic tape, while the low frequency components thereof are recorded in the central portion of the recording tracks.