Abstract: A video disk recorder is such an apparatus as to compresses a video signal contained in a television signal at a predetermined compression rate to record it on an optical disk, and then play back the recorded signal. In such a video disk recorder, the television signal being input into a signal inputting portion is then compressed by a variable-rate encoder, and then sent out to a recording/playing portion. The signal sent out to the recording/playing portion is then recorded on an optical disk. In particular, the video disk recorder has a probability calculating portion for weighting signals according to degree of importance of the contents of the television signals, and a controlling portion for varying the compression rate in compliance with the weight.

Abstract: A data reproducing apparatus includes a memory separate from a recording medium. The memory stores updatable management information indicating an updatable limitation on playback of a content. Data representative of the content are read out from the recording medium. The management information is read out from the memory. A decision is made as to whether playback of the content is permitted or prohibited in response to the management information read out from the memory. When it is decided that playback of the content is permitted, playback of the content represented by the data read out from the recording medium is implemented. The management information in the memory is updated in response to the implemented content playback.

Abstract: A method for variable bit rate encoding is composed of a step of obtaining first encoded data by encoding a video signal in a predetermined bit rate, a step of recording the first encoded data, a step of observing encoded information of the recorded first encoded data, a step of decoding the recorded first encoded data at a predetermined time interval, a step of obtaining second encoded data by encoding the decoded first encoded data in variable bit rate at the predetermined time interval on the basis of either one of a combination of the encoded information and an average variable bit rate to be targeted and another combination of the encoded information and information related to a target code rate, and a step of recording the second encoded data encoded in the variable bit rate. The method for variable bit rate encoding records the first and second encoded data in a recording medium while buffering the first and second encoded data respectively in the steps of recording the first and second encoded data.

Abstract: A data recording apparatus includes a first device for changing a present date represented by first information, and a second device for limiting a number of times the first device changes the present date represented by the first information. The data recording apparatus may further include a third device receiving data, a fourth device for deciding whether or not the present date represented by the first information precedes a date of feed of the data which is equal to a date of the reception of the data by the third device, and a fifth device for, when the fourth device decides that the present date represented by the first information precedes the date of feed of the data, correcting the present date represented by the first information into agreement with the date of feed of the data.

Abstract: In a method of managing the copying of data representing contents, contents and a copyright number given from a copyright holder to the user regarding the contents are sent to a user as virtual contents files whose number is equal to the copyright number. In cases where the user copies the contents from a source recording medium to a destination recording medium, the virtual contents files are moved from the source recording medium and are erased therefrom.

Abstract: An information recording medium provides a first signal recording area (A) on which a first data is recorded, and a second signal recording area (B) which is a signal recording area outer from the first area in the radius direction, records a second data at a density higher than that of the first data, and wherein the second data includes the same contents of information as the first data. The recording density of the second data may be 2 to 10 times that of the first data. The sampling rate, the number of quantized bits, and the number of pixels of the second data may be more than the sampling rate, the number of quantized bits, and the number of pixels of the first data, respectively. The first data may be recorded at a fixed transfer rate, and the second data may be recorded at a variable transfer rate. A music signal of an audible band may be recorded for the first data, and a music signal up to an ultrasound band other than an audible band may be recorded for the second data.

Abstract: A test signal is recorded on a first recording disk according to a constant linear velocity technique. The test signal is reproduced from the first recording disk. A quality of the reproduced test signal is evaluated as a function of a position on the first recording disk. An information signal is recorded on a second recording disk having first and second areas. A degree of deterioration in record quality in the first area is greater than a degree of deterioration in record quality in the second area. A recording density in the recording of the information signal on the first area is decreased below a recording density in the recording of the information signal on the second area. A degree of the decrease in the recording density is changed as a function of a position on the second recording disk in response to the evaluated quality.

Abstract: A reproducing apparatus for reproducing plural types of optical discs comprising: a comparator for digitizing a reproduced signal obtained by reproduction of a first optical disc which is to be reproduced under a first optical condition defined by a first reproducing reference under a second optical condition defined by a second reproducing reference applied to reproduction of a second optical disc having a recording density higher than that of the first optical disc, the comparing operation of the reproduced signal with a reference voltage different from that defined by the first reproducing reference; and a pulse length correction circuit for correcting a pulse length of a digital signal outputted from the comparator such that the pulse length of the digital signal is equal to another pulse length which would be obtained by digitizing another reproduced signal using the reference voltage defined by the first reproducing reference, the another reproduce signal being obtained by reproducing the first optical

Abstract: A reflective optical rotary encoder device detects an angular speed or position of a rotatable member with a light beam applied to and reflected from a reflective optical encoder disc. The reflective optical rotary encoder disc has an annular encoder track for reflecting the light beam, the encoder track being composed of an annular pattern of angularly spaced pit units each including a plurality of radially spaced arcuate pits, and a pit-free annular focus servo track for focusing the light beam onto the encoder track, the focus servo track extending along and being disposed radially substantially centrally in the annular encoder track.

Abstract: An optical apparatus reproduces an information signal recorded as pits along track turns of a rotating recording medium. At least one kind of reference signal is recorded along and overlapping the lateral edges of the adjacent track turns of the information signal. A light source projects a first light beam onto the surface of the recording medium to simultaneously reproduce the information and reference signals. A detector responds to reflections of the projected light which includes and reproduces the information signal and the reference signal. The optical system is controlled so that the center of the light beam coincides with the centerline of the track. A circuit separates the reference signal from the total reproduced signal and produces a tracking control signal in response thereto.The optical system also projects a second light beam onto the recording medium and its reflected component is used for focus control.