A digital video signal record and playback device for recording on a recording medium a digital video signal coded by using a motion compensation prediction and an orthogonal transform and playing back data from the recording medium. In a data arrangement of a digital video signal, an I picture which can be independently represented in a picture is divided into n areas in the vertical direction, and the data is arranged from the front of one GOP in the unit of area by giving a priority to an area located at the center of the screen. A playback picture is outputted by playing back the I picture read from the recording medium in the unit of area unit. In the case where the whole I picture area cannot be read within a definite time, the area which cannot be read are interpolated by the use of the data of the preceding screen.

Digital video signal record and playback device and method for giving priority to a center of an I frame

An excellent picture coding scheme, adapted to suit any particular picture movement, divides an input picture data into two-dimensional small blocks including frame small blocks and field small blocks, then calculates the block activity of the frame and field small blocks. By comparing field block activity with frame block activity, a total of two-dimensional blocks indicating that field block activity is greater than frame block activity is calculated. When the total calculated above is equal to or greater than a predetermined value, frame unit coding is performed. When the total calculated above, however, is below the predetermined value, the frame is divided into odd-and even-numbered fields and a field unit coding is performed for the frame.

Method and apparatus for picture coding and method and apparatus for picture decoding

The quantity of spherical aberration correction is predetermined for each recording plane of an optical disk on which focusing control is performed. Before operating the focusing control, the quantity of spherical aberration to be corrected by an aberration correcting system is set based on an output signal from an aberration correction quantity switching device that corresponds to the type of the optical disk and the recording plane to be subjected to the focusing control. This makes it possible to perform stable focusing control on each recording plane of a multi-layer optical disk with high density by using an objecting lens having a large NA after spherical aberration has been corrected properly.

Optical disk apparatus

Video encoding and decoding methods and apparatuses are provided which are effective for error correction and error concealment in an error-prone environment. The video encoding method includes determining an encoding operation to encode raw video among a frame encoding operation, a top/bottom field encoding operation, and a left/right field encoding operation based on at least one characteristic of the raw video; and generating a bit stream by adaptively performing the encoding operation that is determined to encode the raw video. Further, video may be divided into frame pictures, top/bottom field pictures and left/right field pictures, and encoded accordingly. Therefore, a compression rate can be increased, and error correction and concealment can be effectively performed on a lost field by using a normally received field.

Video encoding and decoding methods and apparatuses

An optical disk apparatus comprising a device for moving a focal point of a light beam for reproducing information recorded on an information face of a disk, in the direction perpendicular to the information face; a device for detecting a reflected light from the disk; and a device for discriminating whether the disk set in the apparatus is a disk having a thick base substrate or a disk having a thin base substrate. In this apparatus, a maximum value AS1Lmax of an output signal from the reflected light detecting device and a maximum value ENVmax of an amplitude of an information reproducing signal are detected while driving the focal point moving device so that the focal point passes through the information face, and the discriminating device discriminates whether the disk set in the apparatus is a disk having a thick base substrate or a disk having a thin base substrate, on the basis of the ratio of ENVmax to AS1Lmax. Therefore, it is possible to discriminate between a DVD having a thin base substrate and a CD having a thick base substrate.

Optical disk thickness discriminating apparatus

PURPOSE:To improve processing efficiency by detecting intra-frame and odd and even inter-field moving vectors and the added difference of the absolute value of each picture element, selecting an efficient mode from movement compensation and respective block division modes, and controlling a frame memories with movement compensation device. CONSTITUTION:Frame/field movement detection circuits 22 and 21 detects the intra-frame and add and even inter-field moving vectors as well as the added difference of the absolute value of each picture element. A movement prediction mode discrimination circuit 23 and a selector 24 select the efficient mode from among the movement compensation modes in the unit of frame/field. A block division mode discrimination circuit 25 selects the efficient mode from among the respective block division modes for frame/field orthogonal transformation. An address generator 11 controls a frame memory group 10 based on the output of the circuit 25, and a frame memory group 20 with a movement compensation device operates based on the outputs of the circuits 23, 25. Thus, the field or frame processing efficiency can be improved.

Image signal high efficiency encoder and decoder

PURPOSE: To discriminate a low density optical disk and a high density optical disk even if they are in the same shape from a signal detected by an optical pickup. CONSTITUTION: An optical disk D is driven to rotate at constant angular velocity at the start-up time by a constant angular velocity driving control circuit 14. Then, an optical pickup 1 is moved into a specific position in the radial direction of the optical disk D, for instance, an innermost circumferential part by a slide movement control circuit 21. A pit length of a track in the innermost circumferential part as in the specific position in the radial direction is measured by a pulse width measuring circuit 8. A max. value in pulse width measured by the pulse width measuring circuit 8, i.e., the max. pit length is held in a max. pulse width hold circuit 10. A min. value in pulse width measured by the pulse width measuring circuit 8, i.e., the min. pit length is held in a min. pulse width hold circuit 11. The kind of an optical disk is discriminated by a disk discriminating circuit 12 in accordance with the max. pit length and the min. pit length. COPYRIGHT: (C)1995,JPO

Optical disk reproducing device

PURPOSE:To obtain high picture quality with less information quantity, to minia turize the scale of the hardware and to reduce a frame buffer in a decoder. CONSTITUTION:A limit mode discrimination circuit 34(a) selects the mode inhibiting the inter-frame prediction coding in all macro blocks in one slicing or the mode inhibiting the inter-field prediction coding in a frame coded at present in all macro blocks in one slicing adaptively. Furthermore, the prediction from an odd number field to an even number field is inhibited in a B frame and the prediction from an odd number field (e.g., Io field) of a forward prediction reference frame is inhibited.

High efficient coding for picture signal, decoder and recording medium

PURPOSE:To relieve the load of the hardware when plural kinds of ranges and accuracy of motion vectors are in existence CONSTITUTION:The system is provided with a ROM 2 forming a variable length code table within a range of + or -2 picture elements A motion vector within a range of + or -2 picture elements is fed to the ROM 2 to obtain a VLC code equivalent to a motion vector within a range of + or -2 picture elements An arithmetic operation circuit 1 divides an X by 2 to obtain a quotient Y and a residue Z, where X is a motion vector within a range of + or -4 picture elements The quotient Y is fed to the ROM 2, an addition circuit 3 adds a residue Z to the output of the ROM 2 to obtain the VLC code equivalent to the motion vector within a range of + or -4 picture elements Thus, it is equivalent with that the vector is coded by a variable length code table within a range of + or -4 picture elements A flag representing whether a range of the motion vector is + or -2 picture elements or + or -4 picture elements is sent and the motion vector is accurately reproduced by the VLC code Since the variable length code table (ROM2) is used to code the motion vector with the range of + or -2 picture elements or + or -4 picture elements and the load of the hardware is relieved

Variable length coding system for motion vector

PURPOSE:To perform the efficient field processing or frame processing even in the case of a picture with little movement, a picture with much movement, or picture consisting of both of them on the field dynamic picture. CONSTITUTION:The coder-decoder is provided with frame/field motion detecting circuits 22 and 21 detecting the motion vector between intra-frame and inter feed and the absolute value differential sum, frame/field mode decision circuit 33 discriminating the first and second modes for the blocking of the motion prediction and the orthogonal conversion, a coding processing mode decision circuit 34 discriminating the coding processing mode for the adaptive changeover of the blocking mode and the coding processing mode taking the blocking mode as the field, an address generator 35 controlling a frame memory group 10 based on the output of the circuit 33, and a frame memory group 20 with motion compensator operating based on the output of the circuits 33 and 34.

勝治五十嵐

Papers

Image signal high efficiency encoder and decoder

Optical disk reproducing device

High efficient coding for picture signal, decoder and recording medium

Variable length coding system for motion vector

High efficiency coder-decoder for picture signal

勝治 五十嵐

Papers

Image signal high efficiency encoder and decoder

Optical disk reproducing device

High efficient coding for picture signal, decoder and recording medium

Variable length coding system for motion vector

High efficiency coder-decoder for picture signal

勝治五十嵐