Abstract: A tampering detection device includes tampering detection circuitry configured to acquire an access pattern of a monitoring target file, extract a time-series pattern of access for each monitoring target file from the access pattern acquired, and determine a scan pattern on a basis of the time-series pattern of access extracted.

Abstract: To achieve a reduction in circuit size without causing output leakage from a frame memory. A frame memory temporarily stores a plurality of input video signals. A plurality of encoders perform compression coding on the video signals read from the frame memory. A control unit controls the operations of writing into and reading from the frame memory. The video signals are written into the frame memory at respective frame frequencies. The video signals are read from the frame memory at a common output frame frequency. The output frame frequency is assumed to be the highest frame frequency or more of the video signals.

Abstract: To achieve a reduction in circuit size without causing output leakage from a frame memory. A frame memory temporarily stores a plurality of input video signals. A plurality of encoders perform compression coding on the video signals read from the frame memory. A control unit controls the operations of writing into and reading from the frame memory. The video signals are written into the frame memory at respective frame frequencies. The video signals are read from the frame memory at a common output frame frequency. The output frame frequency is assumed to be the highest frame frequency or more of the video signals.

Abstract: This invention relates to a data recording and reproduction apparatus, wherein video data VD and audio data AD are recorded in a recording medium while they are mixed in a compressed state respectively, and are reproduced from this recording medium. The video data is recorded in a recording medium in units of a predetermined length, and subsequently thereto, the audio data is recorded in the recording medium in units of a predetermined length. To each head portion of the video data and audio data, header data VH and AH, which are identification information for identifying these data, are added. When the video data and audio data recorded at different areas in the recording medium are reproduced, the access time is shortened by making the head seeking operation on the basis of the header data and reducing the number of seeking operation.

Abstract: A part of the reference signal used as the reference in recording and reproduction is recorded with the polarity thereof being inverted in a data recording medium or in a data recording apparatus in order to positively reproduce recorded data with a simple configuration. When identification signal NRZI for each sector is repeatedly recorded, for example, a part of this identification signal is recorded with the polarity thereof being inverted.

Abstract: A data modulation apparatus for modulating data by run-length limited (1,7) modulation including constant data adding means for receiving input data and adding constant data after the input data, status data producing means for performing, in each modulation period, logical operations on at least part of the data output by the constant data adding means of each modulation period and the status data of the modulation period immediately before each modulation period to produce status data of each modulation period, and modulated data producing means for performing, in each modulation period, logical operations on the data output by the constant data adding means of each modulation period and the status data of the modulation period immediately before each modulation period to perform run-length limited (1,7) modulation and produce modulated data. Also, a data demodulation apparatus, run-length limited (1,7) modulated data recording apparatus, and a recording medium used with the same.

Abstract: A data recording apparatus which simultaneously records data to a plurality of radially divided recording areas of a disc recording medium by the CAV method, including a data dividing unit for dividing the input data into amounts of data proportional to the radial lengths of the plurality of recording areas and a plurality of data recording units for simultaneously recording the data to the corresponding recording areas at data recording rates proportional to the radial lengths of the recording areas; a data reproducing apparatus which reproduces data recorded by such a data recording apparatus including a plurality of data reproducing units, provided corresponding to the data recording areas, for simultaneously reproducing data from the recording areas, and a data rearranging unit for rearranging the data reproduced from the recording areas to the same order as the original input data; and a data recording/reproducing apparatus including such a data recording apparatus and data reproducing apparatus.

Abstract: To improve the reliability of reproduction by performing signal processing so that substantially (almost) all DC is eliminated when digital data is recorded on a recording medium such as a magneto-optical disk. When data is recorded on a recording medium such as a magneto-optical disk, generally the digital data is modulated and encoded before being recorded, but sometimes the modulation code is not DC free due to a recording channel code of an NRZI system, etc. According to the present invention, data is divided into parts each having a certain constant length so as to prevent the DC component from building up.

Abstract: A recording and/or reproducing apparatus for grouping input video data at an interval of a predetermined number of pixels and encoding each block by a DCT circuit, a quantization circuit and an entropy encoding circuit, recording the encoded data on a magnetic tape, and reproducing the magnetic tape for producing block-by-block data, which is decoded to produce output video data, includes a filtering circuit for reducing horizontal and vertical frequency components generated by repetitive occurrences of the respective data blocks. For a differential speed playback mode, such as shuttle playback, the video data reproduced and decoded during the differential speed playback mode is passed through the filtering circuit for producing a satisfactory playback image in which block components are suppressed even for the differential speed playback mode.

Abstract: In a digital information signal reproducing apparatus in which a first digital audio signal and a second digital audio signal having the same contents are recorded on two oblique tracks which are close to each other on a record tape while the latter is run at a normal speed, and in which the first and second digital audio signals are reproduced from the tape by plural rotary heads; a head position controller is operative to control a scanning position of each of the rotary heads so that the latter scan the tracks during variable speed reproduction when the tape is run at a speed different from the normal speed, and to cause the heads to periodically jump over a plurality of the tracks; a detector detects when the rotary heads controlled by the head position controller jump over the plurality of tracks; and a processor responsive to the detector for switching the first digital audio signal and the second digital audio signal, as in a cross-fading operation, for a predetermined period when a jump is detected an

Abstract: In an apparatus, such as a digital video tape recorder, for reproducing data signals recorded on helical scan recording tracks each having a plurality of sectors, with two adjacent tracks forming a segment and three segments forming a field, changes of sector and segment identical data are detected during reproduction, and an error signal is generated when a change in a segment occurs without a change in a sector. Either an error correction circuit or a concealing circuit receives the error signal, and is activated to perform error correction or error concealment. As a result, high quality reproduction is achieved, even in a shuttle reproduction mode.