摘要:
A system that incorporates teachings of the present disclosure may include, for example, distorting a seed image to generate first and second images where the distortions cause the first and second images to have a potential false tie according to a target quality estimator and generating a third image from the first and second images where the third image is generated based on a proxy quality estimator so that the third image has a potential false ordering according to the target quality estimator. Other embodiments are disclosed.
摘要:
A system that incorporates teachings of the present disclosure may include, for example, distorting a seed image to generate first and second images where the distortions cause the first and second images to have a potential false tie according to a target quality estimator and generating a third image from the first and second images where the third image is generated based on a proxy quality estimator so that the third image has a potential false ordering according to the target quality estimator. Other embodiments are disclosed.
摘要:
A method and apparatus reliably encode and decode information over a communication system. The method includes transforming two coefficients into two pairs of random variables, one random variable in each pair having substantially equal energy as one random variable in the other pair. The method further includes quantizing each of the pairs of random variables and entropy coding each quantized random variable separately creating an encoded bitstreams. The encoded bitstreams are received by a decoder which first determines which channels of the communication system are working. The encoded bitstream is entropy decoded, inversed quantized and inversed transformed. An inverse transform performs three different transformations depending upon which channels are working, i.e., whether the first, second or both channels are working.
摘要:
A method and apparatus reliably encode and decode information over a communication system. The method includes transforming two coefficients into two pairs of random variables, one random variable in each pair having substantially equal energy as one random variable in the other pair. The method further includes quantizing each of the pairs of random variables and entropy coding each quantized random variable separately creating an encoded bitstreams. The encoded bitstreams are received by a decoder which first determines which channels of the communication system are working. The encoded bitstream is entropy decoded, inversed quantized and inversed transformed. An inverse transform performs three different transformations depending upon which channels are working, i.e., whether the first, second or both channels are working.
摘要:
Encoder/decoder buffer overflow and underflow encountered when employing actually variable or effectively variable bit-rate channels for communicating encoded video images and corresponding audio signals are overcome by adjusting the parameters of a video encoder in response to a representation of cell delay variation, i.e., jitter, determined at a remote decoder.
摘要:
A video processing system is disclosed that separates and separately encodes and decodes the low and high spatial frequency coefficients of images for transmission or storage. Each block of an image is transformed into the frequency domain. High frequency coefficients of the resulting transform matrix are separated from the low frequency coefficients. The low frequency coefficients are motion prediction compensated to derive motion vectors and a prediction error signal. The motion vectors, prediction error signal and high frequency coefficients are channel encoded for storage or transmission. In a receiver, the motion vectors and prediction error signal are used to reconstruct a low frequency motion-compensated version of the image. The high frequency coefficients are inverse transformed into the pel domain and are combined with the reconstructed low frequency verison of the image to reconstruct a version of the original image.
摘要:
Encoder/decoder buffer overflow and underflow encountered when employing actually variable or effectively variable bit-rate channels for communicating encoded video images and corresponding audio signals are overcome by adjusting the parameters of a video encoder in response to a representation of cell delay variation, i.e., jitter, determined at a remote decoder.
摘要:
A method and apparatus reliably encode and decode information over a communication system. The method includes transforming two coefficients into two pairs of random variables, one random variable in each pair having substantially equal energy as one random variable in the other pair. The method further includes quantizing each of the pairs of random variables and entropy coding each quantized random variable separately creating an encoded bitstreams. The encoded bitstreams are received by a decoder which first determines which channels of the communication system are working. The encoded bitstream is entropy decoded, inversed quantized and inversed transformed. An inverse transform performs three different transformations depending upon which channels are working, i.e., whether the first, second or both channels are working.
摘要:
The quality of video images received at the remote end of an ATM network capable of transmitting data at high and low priorities is greatly improved at high cell loss levels by employing a two-layered video encoding technique that adapts the method for encoding information transmitted in the low-priority bit-stream to the rate of cell loss on the network so that compression efficiency and image quality are high when the network load is low and resiliency to cell loss is high when the network load is high. The encoder adapts its encoding method in response to a cell loss information signal generated by the remote decoder by selecting the prediction mode used to encode the low-priority bit-stream, and by changing the frequency at which slice-start synchronization codes are placed within the low-priority bit-stream.
摘要:
Complications of timing recovery in an ATM receiver are overcome by employing a first phase lock loop including a phase comparator, filter, voltage controlled oscillator (VCO) and output counter to lock to systems clock reference (SCR) values which are asynchronously received from a remote ATM transmitter. The SCR values represent the instantaneous values of a system timing clock (STC) at the instant of transmission of the asynchronous SCR values. In the receiver, the output counter is first set to the value of the initial received SCR value so that the derived STC is available for decoding data cells in the initial received packets. Then, so-called Presentation/Decode Time Stamps (PTS/DTS) included in the audio and video data are advantageously employed in conjunction with STC to display properly the received data. Invention, underflow of the receiver data buffers is alleviated by the addition of a "jitter-delay (D.sub.j)" value which causes an extra accumulation of data in the data buffers prior to decoding. Dynamic tracking of the jitter-delay of the channel is obtained by monitoring the fullness of the data buffers and controllably adjusting the jitter-delay, accordingly. The stability of the decoder video timing is enhanced by employing an additional phase locked loop in a video display control which is supplied with a timing error signal. The additional phase locked loop includes a switch, filter, clipper and voltage controlled oscillator (VCO). The switch is enabled in response to output pulses from the VCO to supply the instantaneous error signal input to the filter for each so-called video presentation unit. The VCO has a very stable center frequency which variation is limited by clipping an input control voltage to some small voltage range. Output pulses from the VCO are employed to enable decoding of the presentation units. Faster synchronization is provided at start-up by increasing, via control of the clipper, the allowable voltage range of the VCO.