Abstract: According to the present invention, when an ATV signal is recorded by a digital VCR in the conventional television signal record mode, variable speed reproduction data composed of HP data containing I frame is redundantly recorded in a surplus record area that is formed by the difference between the transmission rate of the ATV signal and the transmission rate of the conventional compressed digital video signal. When variable speed reproduction is performed, the variable speed reproduction data is reproduced.

Abstract: A coding apparatus and method for intraframe and interframe coding a digital video signal to produce intraframe coded data and interframe coded data, respectively. The intraframe and interframe coded data are both orthogonally transformed to produce transformed intraframe and interframe coded data. Either the transformed intraframe coded data or the transformed interframe coded data is selected in accordance with respective coefficient data of the intraframe and interframe coded data.

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: 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 picture type identifier, indicating one of intra-picture coding (an I-picture), forward or backward predictive coding (a P-picture) and bi-directionally predictive coding (a B-picture), is included with a picture signal when the signal is encoded and when the signal is decoded. Each of initial and subsequent encoding and decoding is a function of the included picture type.

Abstract: In an encoding and decoding method of color signal components of picture signals having a plurality of resolutions, an encoding system and a decoding system can be obtained color pictures with higher definition, so that color difference signals in a format of the macroblock of 4:4:4 are encoded by a circuit 102. These color difference signals with the highest definition are down-sampled by a down sampling circuit 103 and then encoded by a circuit 101. These color difference signals with intermediate definition are further down-sampled by a down sampling circuit 104 to produce the color difference signals with the lowest definition. These color difference signals in a format of the macroblock of 4:2:0 are supplied to and encoded by a circuit 100. Data output from the circuits 100, 101, and 102 are composed by a combining circuit 105 and transmitted.

Abstract: In a video signal transmission system, in which video signals are transformed to high efficiency coded data and are then transmitted, a quantization step size is enlarged when quantizing intra coded picture data to avoid an excessive increase in the amount of data generated. The amount of residual data in a transmission buffer memory is monitored, and frame dropping is initiated when it exceeds a certain predetermined level, but the frame dropping operation is not completed until the amount of residual data falls below a different, smaller predetermined level. Video signals which are sent immediately after a transmission line is connected to a destination are intra coded to enhance system usability.