In a decoding apparatus for decoding data, such as a digital video signal or the like, transmitted with a smaller number of bits than that of the original datum, sample data adjacent a sample datum to be decoded are separated from the transmitted data and compared with the sample datum to be decoded, whereupon a correcting datum is generated on the basis of the compared output. The original datum is recovered from the sample datum to be decoded and the correcting datum, whereby the quantizing error or distortion can be reduced without increasing the amount of encoded data.
In order to reduce the flicker and blur of a result obtained by, for example, converting an interlace scan image into a progressive scan image, an image still area determination device comprises a unit for calculating the average value of the values of the relevant pixel and pixels adjacent to the pixel in each of the current frame image and a frame image immediately before it, a unit for calculating a difference between the average values of a pair of pixels located in the same position of each of two frame images and a unit for determining a still area in each of the two frame images, using its output and a predetermined threshold value.
In a highly efficient coding apparatus, for coding digital video data in a block format and allowing video data compression for transmission using a data transmitter having a predetermined transmission capacity; maximum and minimum values of the digital video data of plural picture elements in a block are detected, the digital video data having values between the maximum value and a first value which is a first predetermined level lower than the maximum value are averaged for generating a modified maximum value, the digital video data having values between the minimum value and a second predetermined level higher than the minimum value are averaged for generating a modified minimum value, the modified minimum value is subtracted from the digital video data for each of the picture elements to generate modified digital video data, modified dynamic range information is generated from the modified maximum and minimum values, an encoding bit number is determined for each block during a predetermined period from the predetermined transmission capacity of the data transmitter, the modified digital video data is subjected to edge-match encoding with the encoding bit number, and an output of the encoder, a first additional code for each block formed of at least two of the modified maximum and minimum values and a signal based on the modified dynamic range information, and a second additional code for each predetermined period referred to above are transmitted.
An input digital information signal is prediction-encoded and thereby difference signals are generated. The difference signals are block segmented. A maximum value and a minimum value of each block are detected. Whether or not the range of levels of the maximum value MAX and the minimum value MIN crosses 0, a mode determining circuit 5 determines a quantizing mode and generates a mode signal MODE that represents the determined quantizing mode. When the range of the levels crosses 0, a first quantizing mode is selected. Otherwise, a second quantizing mode is selected. In the first quantizing mode, the quantizing circuit 6 performs the normal quantizing process. In the second quantizing mode, the quantizing circuit 6 performs a code conversion in such a manner that the number of bits of quantized output data is smaller than that of the normal quantizing process.
An input digital information signal is prediction-encoded and thereby difference signals are generated. The difference signals are block segmented. A maximum value and a minimum value of each block are detected. Whether or not the range of levels of the maximum value MAX and the minimum value MIN crosses 0, a mode determining circuit 5 determines a quantizing mode and generates a mode signal MODE that represents the determined quantizing mode. When the range of the levels crosses 0, a first quantizing mode is selected. Otherwise, a second quantizing mode is selected. In the first quantizing mode, the quantizing circuit 6 performs the normal quantizing process. In the second quantizing mode, the quantizing circuit 6 performs a code conversion in such a manner that the number of bits of quantized output data is smaller than that of the normal quantizing process.
A highly efficient coding system includes a blocking device for dividing input signals representing sampled values into a plurality of blocks and outputting first output signals representing the plurality of blocks. An orthogonal transformation device effects an orthogonal transformation of the first output signals of the blocking device corresponding to the blocks, to divide the results of the orthogonal transformation into a mean component and variation components thereof, and to output the mean component and the variation components. A first normalizing device is provided for effecting interblock normalization of the mean component and the variation components outputted from the orthogonal transformation device and for outputting second output signals representing results of the interblock normalization, and a second normalizing device normalizes variation components of the second output signals of the first normalizing device in each of the blocks.
