Abstract: A compression-coded high definition television signal is decoded and converted to a standard NTSC signal without loss of interlacing so that the resulting picture exhibits smooth motion. The compression-coding of the HDTV signal includes DCT processing to produce an 8.times.8 block of coefficient data. Upon decoding, the upper left quadrant of the coefficient data array is used to form a 4.times.4 subblock of coefficient data but the last row of elements of the subblock is replaced by corresponding elements of the eighth row of the 8.times.8 block of coefficient data.

Abstract: Apparatus for deriving from a motion picture film for transfer to a video recording medium a video signal having increased vertical resolution for display using progressive scanning. In the apparatus, a deriving system derives the video signal from the motion picture film; a flag signal generating circuit generates a flag signal indicating that the video signal is for display using progressive scanning; and a recording system records the video signal and the flag signal in the recording medium. In a method of deriving from an interlaced high-definition video signal an interlaced standard-definition video signal having increased vertical resolution, the interlaced high-definition video signal is converted into a progressive high-definition video signal. The number of pixels in the progressive high-definition video signal is reduced to provide a progressive standard-definition video signal, which is converted into the interlaced standard-definition video signal.

Abstract: Reproducing an input image of reduced resolution with respect to the vertical and horizontal directions in high picture quality by processing a coded bit stream of normal resolution. A difference signal (mismatching error signal) representing the difference between a predicted image of the normal resolution and a predicted image of a half resolution with respect to the vertical and horizontal directions is coded and the coded difference signal is transmitted. When producing the predicted image, image data is subjected to motion compensation according to a specified prediction mode.

Abstract: In an encoder, an input picture of a non-interlace structure is sampled by down sampling to form an interlace picture, and the interlace picture is encoded. The encoded data are decoded to form an interlace decoded picture, and the interlace decoded picture is sampled by up sampling and utilized as a predictive picture upon encoding of the non-interlace input picture. In a decoder, a bit stream corresponding to an interlace picture of a low resolution is decoded into an interlace decoded picture. The interlace decoded picture is sampled by up sampling and is utilized as a predictive picture upon decoding of a bit stream corresponding to a non-interlace picture of a high resolution.

Abstract: A digital data reproducing apparatus and method which allows reproduction for a long period of time without deterioration in picture quality. Data are reproduced from an optical disk by a pickup and are transferred to and stored in a ring buffer memory. Data read from the ring buffer memory are transferred to and stored into a video code buffer of an encoder section. The data stored in the video code buffer are encoded in the encoder section and displayed on a display. A track jump judging circuit produces a track jumping instruction to cause the pickup to track jump back to a preceding track when the amount of data stored in the ring buffer memory reaches a predetermined value.

Abstract: A method for coding an input video signal with a field rate of 60 Hz derived from a motion picture film source using 2-3 pulldown. In the method, duplicate fields are detected in the input video signal. Each duplicate field is eliminated from the input video signal to produce a progressive video signal comprising plural frames with a frame rate of 24 Hz. Finally, the progressive video signal is coded to produce a coded video signal. Preferably, when a duplicate field is detected in the input video signal, a control signal is generated in response to each detected duplicated field. Each control signal is then included in the coded video signal.

Abstract: In connection with compression-coding of video signals on the basis of inter-frame correlation, a single reference table is used for variable length encoding of inter-frame motion vectors established on the basis of various motion vector value ranges and degrees of accuracy. A reference table is provided for variable length encoding motion vectors based on a particular value range and degree of accuracy. In order to use the same table for motion vectors based on a larger value range than that for which the table was designed, the value of a motion vector to be encoded is divided to form a quotient and a remainder. An addition bit code is formed on the basis of the remainder and is appended to a variable length code which corresponds in the reference table to the quotient so that a variable length code value is formed for the motion vector based on the larger range.

Abstract: A motion picture coding and decoding system is provided, which permits high picture quality to be obtained with less information amount than that in case of a system having the sole function of DCT coding, permits reduction of block distortion of reproduced picture and permits coding efficiency increase. One picture frame is divided into a plurality of blocks for block-by-block coding. At this time, discrete cosine transform (DCT) coding and intra-block non-transform coding (NTC) are adaptively switched one over to the other according to the character of pattern. In case of the intra-block non-transform coding, predictive values of block and quantizing width are transmitted. Each block is adaptively selected with sub block of frame construction or sub block of field construction.

Abstract: A video image data decoding apparatus includes a pair of buffer memories for storing decoded intra coded picture data or forward prediction coded picture data, a switch circuit for selecting either the decoded intra coded picture data or forward prediction coded picture data to be sequentially stored in the pair of buffer memories, and a generating circuit utilizing picture data stored in one of the pair of buffer memories for generating picture data to be stored into another buffer memory and also utilizing picture data stored in one buffer memory for generating picture data to be newly stored again into the same buffer memory. The generating circuit performs motion compensation by utilizing picture data stored in one buffer memory for generating picture data to be stored into another buffer memory.

Abstract: A ROM containing a variable length coding table for a 2 picture element range is provided. A motion vector within the range of 2 picture elements is provided to the ROM to produce a VLC code corresponding to the motion vector within the range of 2 picture elements. In a calculation circuit, assuming that the value of a motion vector within the range of 4 picture elements is X, a quotient Y and a remainder Z are obtained by the division of X by 2. The quotient Y is supplied to the ROM and the output of the ROM is added the remainder Z at an addition circuit to obtain a VLC code corresponding to the motion vector lying within the range of 4 picture elements. This is equivalent to variable length coding for a 4 picture element range. By transmitting a flag indicating whether the motion vector range is 2 picture elements or 4 picture elements, the motion vector is correctly reproduced from the VLC code.

Abstract: Coded moving picture data is recorded in groups of frames, each frame representing a video image frame and each group being formed of intraframe, interframe and interpolated frame coded data signals. Typically, at least one interpolated frame coded data is derived, in part, from a video image frame that is represented in a preceding group of frames. If a recorded group of frames is edited, said at least one interpolated frame coded data in the edited group of frames no longer is related to the preceding group of frames on the record medium and, similarly, the interpolated frame coded data in the group of frames that immediately follows the edited group of frames no longer is related to the recorded group of frames which precedes it. Accordingly, an edit flag is set in the edited group of frames and/or in the immediately following group of frames to apprise decoding circuitry not to decode the said at least one interpolated frame coded data.

Abstract: In a method for encoding successive frames of a digital motion video signal in the form of compressed digital data including an intraframe coded signal and a plurality of interframe coded signals, a first frame of the digital motion video signal is encoded to form one of an intraframe coded signal and an interframe coded signal to produce a compressed digital signal; the compressed digital signal is decoded to form a decoded signal; a plurality of predicted video signal frames are produced representing a second frame of the digital motion video signal other than the first frame, at least one of the plurality of predicted video signal frames being produced with the use of the decoded signal and a motion vector representing motion between frames of the digital motion video signal; the plurality of predicted video signal frames are compared with the second frame of the digital motion video signal for producing a plurality of difference data each corresponding with a respective one of the plurality of predicted v

Abstract: Image data is recorded in successive turns on a rotatable record medium driven at substantially constant linear velocity by converting a first of successive image frames of image data to an intraframe code signal, converting the (n-1) next-following frames to (n-1) interframe code signals, and recording the intraframe and (n-1 ) interframe code signals on the record medium. In one embodiment, n is the maximum number of image frames that can be recorded in the innermost turn of the record medium and n is constant for all turns, whereby the same number (n--1 ) of interframe code signals separate successive intraframe code signals from turn to turn. In another embodiment, n is a variable and increases as the radius of the turn in which the code signals are recorded increases, whereby a larger number (n-1) of interframe code signals separate successive intraframe code signals as the turn radius increases.

Abstract: In a video signal coding method for generating transmission data, a digital video signal is quantized by a quantization step which is controlled on the basis of significant picture information to be transmitted. The significant picture information is, for example, the quantity of information in a main region and in a sub region, the quantity of picture information to be coded, the picture motion in coded regions, the amount of variations in picture information between regions to be coded, or the components of spatial frequency with respect to regions to be coded. By reason of such control of the quantization step, deterioration of picture quality of the transmission data can be avoided, while the quantity of transmitted data is reduced.

Abstract: Video signal transmitting system in which digital video signal are divided into groups of predetermined frames. Digital video signals of at least one frame are intraframe coded and then transmitted. Remaining digital video signals are interframe coded with reference to the intraframe coded digital video signals, and intraframe coded digital video signals of a subsequent group of frames and are then transmitted. A motion vector from a predetermined reference frame is detected. Video signals are interframe coded by the motion vector to transmit the video signals. A motion vector from a first frame which is a plurality of frames away from the reference frame is converted to a motion vector for a one frame interval between the reference frame and the first frame. The motion vector is optimized, and is then transmitted.

Abstract: A method of encoding a video signal into highly efficiently encoded data comprises the steps of: digitizing and blocking the video signal; performing a discrete cosine or Fourier transform on the blocked data; controlling the amount of data in each block to be substantially constant according to an amount of encoded data awaiting transmission; calculating a threshold amplitude; and selecting data larger in amplitude than the threshold amplitude as encoded data for transmission.

Abstract: Intraframe coding and interframe coding are selectively employed for generating a compressed digital video frame in order to record a motion video signal on a small capacity recording medium such as a CD ROM. Motion compensation is also employed for effective compression, and motion compensation in only one direction is applied to an area of the frame in which interframe coding is applied that corresponds to an area of a previous frame in which the intraframe coding was applied.

Abstract: A key signal generating apparatus for a digital chromakey system for generating a key signal in accordance with the difference between a reference hue corresponding to a back color data and a hue of an input video data in U-V chroma signal coordinates, in which the gain of key signal is determined by quadratic curve groups in the U-V chroma signal coordinates.