Abstract: Systems and methods of dynamically adapting multimedia data transmit rates of data senders to available bandwidths of data receivers, in which the available bandwidths are estimated by the data senders using at least reception quality feedback information provided in real-time transport control protocol (RTCP) report packets. The data senders can obtain several bandwidth estimation parameters, such as a packet loss ratio and a round trip delay, from the reception quality feedback information, as well as multimedia data transmit rates from the data senders to the data receivers, and obtain estimates of the available bandwidths of the data receivers using at least the bandwidth estimation parameters and multimedia data transmit rates. Further, using the estimated available bandwidth, the data senders can dynamically adapt the multimedia data transmit rates to the available bandwidths for more reliably achieving the quality of experience (QoE) desired and/or required for multimedia data transmissions.

Abstract: Systems and methods of handling packet errors associated with multimedia data received at data receivers from data senders, in which packet error feedback information is provided by the data receivers to the data senders in one or more real-time transport control protocol (RTCP) feedback packets. The data receivers can calculate, determine, or otherwise obtain costs associated with providing specific forms of packet error feedback information in the RTCP feedback packets, and further calculate, determine, or otherwise obtain wait times for handling out-of-order packets, as well as receiving retransmissions of lost packets. By handling packet errors associated with multimedia data while taking into account such costs and wait times, each of which can have an impact on system bandwidth and/or latency, the systems and methods can more reliably achieve the quality of experience (QoE) generally desired and/or required for multimedia data transmissions.

Abstract: Systems and methods that employ an application-assisted approach to adaptive spatio-temporal error concealment in video decoders. The systems and methods employ a video receiver that can receive real-time video frames from a video transmitter over a wired and/or wireless network. The video receiver includes an end system configurable as an application for consuming the content of the real-time video frames. The end system application can determine whether each received real-time video frame is complete or incomplete, whether each received slice is complete or incomplete, and provide such information to the video decoder for use in avoiding errors while decoding the respective real-time video frames.

Abstract: Systems and methods of performing rate control in scalable video encoders that can be used to provide videoconferencing, announcements, and live video streaming to multiple participant devices having diverse bandwidths, resolutions, and/or other device characteristics. The systems and methods can accommodate different target bit rates of the multiple participant devices by operating on scalable video bitstreams in a multi-layer video format, including a base layer having one or more reference video frames, and an enhancement layer having one or more disposable non-reference, predictive video frames.

Abstract: Systems and methods of video conferencing, in which existing video encoders associated with a multipoint control unit (MCU) can be shared among conference participant devices, depending upon the availability of processor and/or memory resources for the MCU. In making decisions regarding the sharing of video encoders, the systems and methods take into account various parameters associated with potential conference participant devices and the total cost of the processor/memory resources for the MCU, to determine whether a video encoder of the MCU can be shared with, or allocated to, the respective conference participant devices. By determining whether to share or allocate a video encoder of the MCU, depending upon the available processor/memory resources for the MCU, the MCU can be made to operate with increased stability. The systems and methods can be applied to any application that sends the same content to multiple receivers, including announcement and video streaming applications.

Abstract: Provided are methods and systems for rate-distortion optimized quantization and for skipping transform blocks that can take into account the rate-distortion tradeoff as well as the perceptual quality of reconstructed video.

Abstract: Provided are methods and systems for rate-distortion optimized quantization and for skipping transform blocks that can take into account the rate-distortion tradeoff as well as the perceptual quality of reconstructed video.

Abstract: A rate control algorithm for a predictive video encoder is provided to accurately control the coding rate while requiring a small complexity. The algorithm assumes the video encoder to consist of two processors, pre-processor and main processor, and the rate control located in main processor uses prediction cost and residual cost for each picture that are computed in pre-processor. Prediction cost represents the estimated number of bits needed to generate an error image, and residual cost describes the difficulty of encoding the resultant error image. Accurate and simple rate control is made possible by using a new rate model that adapts to the local characteristic of a video sequence, and by targeting to maintain the quantization parameter as constant as possible in a given set of pictures, GOP, instead of the conventional two step approach.

Abstract: Methods and apparatus for performing near lossless-concatenated N-level constrained quantization Hadamard transform decoding are provided. Accordingly, the present invention provides a transform-based coding technique, where the coding loss introduced during repeated encoding and decoding is reduced to a substantially insignificant level. This is accomplished by employing a constrained quantization and inverse quantization operation in each level of encoding/decoding in the decoder. In this manner, the concatenation error between each level of a decoder is reduced to a substantially minimum level and the quantization error introduced during quantization operations, i.e., originally at the encoder and in each level of the decoder, is substantially reduced. Thus, the decoded bit stream that is output at the N-th level of the decoder is substantially the same as the original bit stream provided to the input of the encoder.

Abstract: A method for providing an AIN (Advanced Intelligent Network) switching system employing a thread call structure with timers for threads by providing a plurality of timer items respectively for the produced threads, wherein each of the timer items includes a thread ID region for storing the identifying data of the corresponding thread, a timer ID region for storing the identifying data of the corresponding timer, a time count region for storing the count data which represents the time taken for driving the corresponding timer item of the corresponding timer, a rear pointer region for detecting the previous timer item, and a front pointer region for detecting the subsequent timer item. The structure further providing a head item for starting a timer drive process every second, wherein the head item includes a head region for storing the head information and a front pointer region for indicating the timer item having the shortest count data.

Abstract: A technique for use in a block transform-based coding system of processing (e.g., encoding and/or decoding) one or more block transform coefficients associated with at least one block of visual data (e.g., an image and/or video sequence) comprises the following steps. First, one or more previously reconstructed block transform coefficients associated with the visual data are identified. Then, a context selection value is computed for use in processing a block transform coefficient associated with the at least one block, the context selection value being based on the one or more previously reconstructed block transform coefficients. The context selection value may be computed as a function of one or more values respectively associated with one or more previously reconstructed block transform coefficients in near proximity, with respect to a scanning order, to the block transform coefficient to be processed.

Abstract: A system and method to convert a CIF compressed video to a QCIF video bitstream provides compatibility between the various digital video sources and application uses. A coding mode and a motion vector for a macroblock in a QCIF video sequence are selected from those of a corresponding CIF video sequence without motion estimation.

Abstract: A technique is provided for use in a video processing system for selecting between an inter-frame coding mode and an intra-frame coding mode when processing a current portion of a video sequence. The technique includes identifying previously reconstructed samples associated with the current portion from a current frame and a reference frame of the video sequence. Then, a selection is made whether to implement the inter-frame coding technique or the intra-frame coding technique on the current portion based on comparisons associated with the previously reconstructed samples. The technique may be implemented in both a video encoder and a video decoder. As a result, the encoder does not need to transmit coding mode-related overhead information to a corresponding decoder. By way of example, the invention may be implemented in a pixel-based coding system or a block transform-based coding system.

Abstract: There is provided a private branch exchange (PBX) system for interworking a digital telephone with a computer such as a personal computer (PC). In the private branch exchange system, a switch has a subscriber interface, a computer telephony interface module (CTIM) is connected to the subscriber interface of the switch, the digital telephone is connected to the switch through the computer telephony interface module, and the computer is connected to the switch through the computer telephony interface module and interworks with the digital telephone. The computer telephony interface module sends a computer-directed message generated from the switch to the computer and sends both the switch and the computer a call origination event message received from the digital telephone.

Abstract: A method of encoding a video sequence including a sequence of video images includes comparing elements of a portion of a first video image with elements of a portion of a second video image to generate respective intensity difference values for the element comparisons. Then, a first value is assigned to the intensity difference values that are at least above a visually perceptible threshold value and a second value is assigned to the intensity difference values that are not at least above the visually perceptible threshold value. Next, the method includes dividing the portion of the first video image into sub-portions and summing the first and second values associated with each corresponding sub-portion to generate respective sums. If a respective sum is at least greater than a decision value, a variable associated with that sub-portion is set to a first value. If a respective sum is not at least greater than the decision value, the variable associated with that sub-portion is set to a second value.

Abstract: A method of perceptually quantizing a block of an image or video sequence includes generating a non-perceptibility of distortion value. The non-perceptibility of distortion value is calculated from one or more masking values, e.g., complexity, brightness, movement, etc., which themselves are respectively calculated from previously reconstructed samples associated with the image or video sequence. The reconstructed samples form one or more causal templates that are used to calculate such masking effects and, thus, the non-perceptibility of distortion value. The perceptual quantization method then includes generating a quantization step size value which is a function of the non-perceptibility of distortion value. Since templates consisting only of previously reconstructed samples are used to derive the quantization step size value, the templates used at the encoder are also available at the decoder.

Abstract: A method of generating a motion vector associated with a current block of a current frame of a video sequence includes searching at least a section of a reference frame to identify previously reconstructed samples from the reference frame that best estimate motion associated with previously reconstructed samples from the current frame associated with the current block. The previously reconstructed samples may form sets of samples. Such sets may be in the form of respective templates. The method then includes computing a motion vector identifying the location of the set of previously reconstructed samples from the reference frame that best estimates the set of previously reconstructed samples from the current frame associated with the current block. It is to be appreciated such a motion estimation technique is performed in both a video encoder and video decoder so that motion vector data does not need to be transmitted from the encoder to the decoder.

Abstract: A new method for real time implementation of rate-distortion optimized coding mode selection is disclosed that can be efficiently applied to H-263-compatible video codecs and other codecs of similar type. A normalized rate-distortion model is used to efficiently compute the rate and the distortion when encoding motion-compensated prediction error signals, instead of performing DCT, quantization and entropy-encoding. A fast algorithm is also disclosed that determines sub-optimal values of coding parameters such as the quantization parameter and the Lagrangian multiplier, .lambda., for the trellis search. Very good rate control and picture quality are achieved, especially when the disclosed techniques are applied in very low bitrate video coding.