Abstract: The digital VTR includes an extractor, variable-length decoder, quantizer and variable-length encoder. The extractor receives digital data divided into blocks, and which is quantized and variable-length coded on a block-by-block basis. Portions of the digital data are encoded according to a first type of encodation, and other portions of the digital data are encoded according to a second type of encodation. The extractor identifies and extracts the digital data encoded according to the first type of encodation. The variable-length decoder variable-length decodes the extracted portions of the digital data, while the quantizer quantizes the decoded data output by the variable length decoder. The variable length encoder variable-length encodes the quantized decoded data to form special-playback data. Alternatively, a convertor converts the extracted portions of the digital data into variable-length coded data having different quantization steps to form the special-playback data.

Abstract: A data separating device extracts intra-frame or intra-field encoded blocks from an intra-frame or intra-field encoded, and inter-frame or inter-field encoded digital video signal, and a digital audio signal contained in an input bit stream. An error correction code appending device appends error correction codes to the extracted intra-encoded blocks. A recording device records the data having the error correction code appended, in special replay data recording areas predefined on the magnetic recording tape. During fast replay or slow replay, error correction is achieved even for the replay signal with a low output level and a poor symbol rate.

Abstract: In a digital VTR which receives at least a digital video signal input in the form of a bit stream, and which records the bit stream according to a transparent recording method, header information is extracted from the bit stream and modified. Intra-coded block components are also detected and extracted from the bit stream, and one track is configured with an area for recording the input bit stream and an area for recording fast playback HP data. Extracted as the intra-coded block components are a predefined number of orthogonal transform coefficients, and the fast playback HP data is configured without appending EOB codes to the intra-coding block components. Alternatively, EOB codes are appended except that the shortest EOB code from a plurality of code maps is used.

Abstract: In a digital signal playback device for playing back data from a recording medium on which intraframe, intrafield, interframe or interfield encoded digital video signals and digital audio signals input in the form of packets have been recorded transparently, and special playback data for special playback generated from said intraframe or intrafield encoded digital video signals has been recorded at predetermined positions, the special playback data is separated from a playback signal during special playback, and stored in a data storage circuit stores the separated special playback data. A still image slice data generator generates slice data with the motion vectors being 0 and prediction errors being 0 for all macroblocks in the slice.

Abstract: A video signal recording and reproducing apparatus for recording a video signal whose information amount is compressed using a high-efficiency encoding employing an orthogonal transform, wherein encoded data obtained by encoding only low-frequency coefficients are recorded separately from normal encoded data. When the amount of information after compression falls short of a presdetermined amount available for recording, the encoded data of low-frequency coefficients are added to fill the vacancy. For the low-frequency coefficients, check words are appended that which provide a greater minimum distance compared with other coefficients. The low-frequency coefficients are doubly encoded for error-correction.

Abstract: A video scan converter has a deflickering circuit that attenuates spatial frequency components that combine high vertical spatial frequency with low horizontal spatial frequency. The resulting signal is converted from progressive scanning to interlaced scanning by appropriate selection of even and odd horizontal scanning lines. The deflickering circuit may also expand a selected part of the video signal by vertical interpolation, followed by vertical low-pass filtering, in which case a separate horizontal interpolating circuit expands the selected part horizontally, preferably after progressive-to-interlaced scan conversion.

Abstract: A magnetic recording and reproduction apparatus wherein the drum motor is controlled so that the rotation number of the drum during playback at the normal speed multiplied by N (N is an integer) changes by a fixed factor to R(1+q/Q) (Q, q are integers satisfying .vertline.q.vertline.<.vertline.Q.vertline.), assuming the rotation number of the drum during normal playback as R rpm. Also a magnetic recording and reproduction apparatus wherein the drum motor is controlled so that the average rotation number of the drum during playback at the normal speed multiplied by N (N is an integer) becomes approximately R rpm by changing the rotation number of the drum periodically and combining a rotation number of R rpm or less and a rotation number of R rpm or more, assuming the rotation number of the drum during normal playback as R rpm.

Abstract: A high-efficiency encoding apparatus having a data division circuit which applies 1-dimensional scanning to the orthogonal-transformed data obtained by applying orthogonal transformation to blocked digital data in the unit of block and divides the data into run-length data and coefficient data, an encoding circuit which applies run-length encoding to the divided run-length data by employing data of the highest probability of occurrence (for example 0), and an encoding circuit which applies run-length encoding to the divided coefficient data by employing data of the highest probability of occurrence (for example 1), thereby reduces the amount of the digital data.

Abstract: A magnetic type recording and reproducing apparatus comprises means for extracting by a first head and a second head a plurality of pilot signal components and means for finding an error for control of tracking with using a proper pilot signal component in accordance with a data rate of signals.The magnetic type recording and reproducing apparatus controls a recording tape speed in accordance with the data rate of signals, controls a playback tape speed in accordance with a high playback speed and the data rate, and arranges high speed playback data in areas which are to be traced by both heads during a playback with a plurality of data rates.

Abstract: In a magnetic recording/playback apparatus for recording and playing back a digital video signal on a helical track of a magnetic tape using two or more rotary heads, the playback image at the time of high-speed playback is improved by setting the tape travel speed at the time of high-speed playback at an even multiple of a normal playback speed. Further, a tracking phase is offset by one half the track pitch with respect to the tracking during normal speed playback. Alternatively, essential information of the information having been high-efficiency coded is recorded in the central part, and near the ends of the tracks, while high-precision information is recorded in intermediate parts intermediate between the central part and the parts near the ends. Still alternatively, the video data of one of the consecutive fields is recorded in the central part of the tracks and the video data of the other of the consecutive fields is recorded near the ends of the tracks.

Abstract: In a digital signal recording and playback device, the transmission rate of input transport packets is identified. A recording mode, a rate at which data is to be recorded, is set on the basis of the identified transmission rate. Intra-frame or intra-field coded digital video data is extracted from the transport packets, and the extracted intra-frame or intra-field coded digital video data is reconstructed to generate special playback data. A recording format is generated such that the input transport packets and special playback data will be recorded at predefined positions on a track of a recording medium. The number of repetitions of the special playback data to be recorded on the recording medium or the recording format is varied depending on the recording mode. Because of the improvement in the recording rate of the fast playback data, the playback picture quality during fast playback can be improved.

Abstract: A magnetic recording and reproducing apparatus wherein synchronizing separation of a reproduction video signal can be performed accurately and a stabilized reproduction video signal can be obtained. The magnetic recording and reproducing apparatus includes a switch device for selectively inserting, upon recording, a PCM modulated audio signal into a blanking period of an FM modulated video signal, a PCM region signal generator for identifying a region of a PCM modulated audio signal in a reproduction signal reproduced by a rotary head and generating a control signal representative of a PCM audio signal region, an FM demodulator for FM demodulating a reproduction signal from the rotary head into a reproduction FM demodulation signal, and a clip circuit for clipping a lower end portion of a PCM audio signal region of a reproduction FM demodulation signal from the FM demodulator in accordance with a control signal generated from the PCM region signal generator.

Abstract: A codeword contains information symbols representing elements of a Galois field, a parity check symbol generated using a certain element of the Galois field, and additional check symbols generated using a polynomial of which this certain element is not a root. The reliability of corrected codewords is assessed by counting the number of symbols found to be in error, or by counting the number of symbols having at least a certain number of bits in error. When a row-column array is decoded, rows of intermediate reliability are not corrected but their error patterns are stored in a memory, and columns of intermediate reliability are corrected if their error patterns match the error information stored in the memory.

Abstract: To reduce the undetected errors without degradation of the burst error correction capability, in error correction decoding of the digital signal with three-dimensional error correction codes appended thereto. For correcting errors by applying error correction codes in three directions of a recording direction, perpendicular direction, and direction of tracks, whether a burst error has occurred is checked, and an error-correction decoding algorithm is switched between one used when a burst error has occurred, and one used when no burst error has occurred.

Abstract: Data separating means extracts intra-frame or intra-field encoded blocks from an intra-frame or intra-field encoded, and inter-frame or inter-field encoded digital video signal, and a digital audio signal contained in an input bit stream. Error correction code appending means appends error correction codes to the extracted intra-encoded blocks. Recording means records the data having the error correction code appended, in special replay data recording areas predefined on the magnetic recording tape. During fast replay or slow replay, error correction is achieved even for the replay signal with a low output level and a poor symbol rate.

Abstract: A digital video signal recording and reproducing apparatus which obtains a favorable reproduced picture even when the data overwritten by edited data is interpolated with the data of the preceding field or preceding frame by recording the video data of the visually inconspicuous peripheral area on a track that is possibly overwritten by the editing data at a cut-in point or cut-out point in assemble editing or insert editing. The apparatus further obtains a natural picture without any fixed error even in speed search mode by exchanging the recording order of the video data of one field on plural tracks according to the head scanning trace in the speed search.

Abstract: A high-efficiency encoding apparatus having a data division circuit which applies 1-dimensional scanning to the orthogonal-transformed data obtained by applying orthogonal transformation to blocked digital data in the unit of block and divides the data into run-length data and coefficient data, an encoding circuit which applies run-length encoding to the divided run-length data by employing data of the highest probability of occurrence (for example 0), and an encoding circuit which applies run-length encoding to the divided coefficient data by employing data of the highest probability of occurrence (for example 1), thereby reduces the amount of the digital data.

Abstract: Fast speed playback is performed with a reduced error-correcting capability as compared with that for normal speed playback. Information of K symbols is encoded with a first error-correcting code C1 and appended with (N-K) check symbols. After that, m symbols out of the check symbols are punctured, and the information of K symbols is divided into a block of K.sub.1 symbols and a block of K.sub.2 symbols, the block of K.sub.1 symbols being further encoded with a second error-correcting code Cm and appended with m.sub.1 check symbols for error correction. For efficient error-correction coding of auxiliary data which is usually not used but which becomes necessary on occasions, the presence or absence of auxiliary data is written in ID information, and the number of error-correcting check symbols is changed accordingly.

Abstract: In an error-correcting apparatus for correcting errors included in reproduced data which are stored in a RAM, a syndrome generation circuit, a polynomial calculation circuit for calculating an error position polynomial and an error value polynomial, and a position calculation circuit for calculating an error position are operated in parallel. A divider section of the error-correcting apparatus has a divider for performing the division of highest-degree coefficients of two polynomials, a multiplier for multiplying the coefficient of the polynomial set in the divisor side of the divider by the output of the divider, and an adder for adding the output of the multiplier and the coefficient of the polynomial set in the dividend side of the divider. The divider section executes the division over a Galois field while sequentially shifting the contents of registers which store the coefficient data of the dividend polynomial.

Abstract: In an error-correcting apparatus for correcting errors included in reproduced data which are stored in a RAM, a syndrome generation circuit, a polynomial calculation circuit for calculating an error position polynomial and an error value polynomial, and a position calculation circuit for calculating an error position are operated in parallel. A divider section of the error-correcting apparatus has a divider for performing the division of highest-degree coefficients of two polynomials, a multiplier for multiplying the coefficient of the polynomial set in the divisor side of the divider by the output of the divider, and an adder for adding the output of the multiplier and the coefficient of the polynomial set in the dividend side of the divider. The divider section executes the division over a Galois field while sequentially shifting the contents of registers which store the coefficient data of the dividend polynomial.