摘要:
The present invention is an apparatus and method to remove delay fluctuations generated on a plurality of networks.A reception apparatus 22 receives ATM cells transmitted through a network 4-1 and a network 4-2, converting the cells into a transport stream. At that time, the reception apparatus 22 expresses a PCR packet's timing of arrival at the reception apparatus 22 by a count value obtained as a result of counting the number of clock pulses (clock pulses Nr) synchronous with a network clock signal of the network 4-2. The reception apparatus 22 also computes a new PCR value W on the basis of the count value and the phase-difference information used as synchronization information. The reception apparatus 22 then computes a new PCR value X on the basis of an original PCR value E recorded from the beginning on the encoding side and the PCR value W, newly recording the PCR value X.
摘要:
A transmission side of a communication apparatus of the present invention makes use of a clock signal synchronized with a network to transmit an arrival interval of a PCR packet in which a PCR value is included and a synchronization residual. A reception side of the communication apparatus of the present invention calculates delay fluctuations caused by the network from the arrival interval and the synchronization residual included in the received PCR packet and modifies the PCR value based on the delay fluctuations.
摘要:
Synchronous information indicates a difference (&bgr;) between a PCR value E and a counter value N (=3240000), if the third PCR packet is assumed to arrive at a transmitting apparatus 201 at the time (time t1) the count value N becomes 3240000, on the basis of a difference (&agr;) between the PCR value E3 and the count value N3, both generated while as many clocks as (count value N3—reference clock value B) are being counted. Hence, the delay fluctuation generated on a network can be eliminated.
摘要:
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.
摘要:
Encoding parameters of picture and higher layers of importance to a number of applications, and encoding parameters of slice and lower layers of no importance to all applications are converted into auxiliary packets inserted respectively into a V-blanking area and an H-blanking area of a video-data signal output by a history-information-multiplexing apparatus employed in a video-decoding system. On the other hand, a video-encoding system extracts back the auxiliary packets superposed on the V-blanking area and the H-blanking area from an input base-band video signal. As a result, a technique of superposing information on data can be changed in accordance with the importance of the information and required information can be fetched with ease.
摘要:
A picture encoding method in which the picture signal can be scrambled without deteriorating the picture quality of the encoded picture of the MPEG system. A B-picture f the input picture signal is given random offset in the horizontal direction on the slice basis and encoded by an MPEG encoding device. An offset amount is written as a key on the disc along with the encoded data. A decoding device corrects the offset amount in the slice basis using the key of the reproduced signal. The picture signal can be scrambled in this manner without modifying the MPEG system.
摘要:
A method for encoding a digital signal which is free from overflow and/or underflow of decoder buffer when video and audio data are reproduced while switching a plurality of bit streams from one to another, is disclosed. The method includes the steps of receiving a plurality of digital signal bit streams, detecting sizes of access units, as an encoding unit, of the plural digital signal bit streams, and decode times thereof, comparing the detected sizes of the access units at each decode time, with each other to select a maximum value thereof, providing a virtual stream composed of access units each having a size identical to the selected maximum value at each decode time, and packetizing each of the plural digital signal bit streams, wherein the plural digital signal bit streams are packetized by using padding packets each having a size corresponding to a difference in size between each access unit of the plural digital signal bit streams and that of the virtual stream, when the size of the access unit of the plural digital signal bit streams is less than the size of the access unit of the virtual stream. In accordance with the present invention, there are also provided an apparatus for encoding the digital signal, a method for recording the digital signal on a recording medium, and a method for transmitting the digital signal.
摘要:
A method and apparatus for encoding moving picture signals. A plurality of encoding picture groups, each consisting of a pre-set number of encoding pictures freed of redundant pictures from a plurality of original pictures represented by the input moving picture signals, are formed, and the number of original pictures used for forming the encoding picture groups and the group-based target bit amount are calculated. The moving picture signals of the encoding pictures are encoded from one picture group to another based upon the target bit amount. Even if the encoding picture rate is changed from one picture group to another, the target bit amount can be adaptively controlled with these changes in the encoding picture rate. Consequently, there is no risk of the output bit rate significantly surpassing the target value. In addition, there is no risk of the total bit amount in the bit stream exceeding the target amount to render it impossible to record the bit stream on a desired moving picture signal recording medium.
摘要:
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.
摘要:
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.