Abstract: The disclosure is directed to techniques for region-of-interest (ROI) coding for video telephony (VT). The disclosed techniques include a technique for generation of a quality metric for ROI video, which jointly considers a user's degree of interest in the ROI, ROI video fidelity, and ROI perceptual quality in evaluating the quality of an encoded video sequence. The quality metric may be used to bias ROI coding and, in particular, the allocation of coding bits between ROI and non-ROI areas of a video frame.

Abstract: The disclosure is directed to techniques for region-of-interest (ROI) processing for video telephony (VT) applications. According to the disclosed techniques, a recipient device defines ROI information for video information transmitted by a sender device, i.e., far-end video information. The recipient device transmits the ROI information to the sender device. Using the ROI information transmitted by the recipient device, the sender device applies preferential encoding to an ROI within a video scene. ROI extraction may be applied to process a user description of a region of interest (ROI) to generate information specifying the ROI based on the description. The user description may be textual, graphical, or speech-based. An extraction module applies appropriate processing to generated the ROI information from the user description. The extraction module may locally reside with a video communication device, or reside in a distinct intermediate server configured for ROI extraction.

Abstract: The disclosure is directed to techniques for region-of-interest (ROI) processing for video telephone (VT) applications. According to the disclosed techniques, a recipient device defines ROI information for video information transmitted by a sender device, i.e., far-end video information. The recipient device transmits the ROI information to the sender device. Using the ROI information transmitted by the recipient device, the sender device applies preferential encoding to an ROI within a video scene. In this manner, the recipient device is able to remotely control ROI encoding of far-end video information by the sender device.

Abstract: The disclosure is directed to techniques for content-adaptive background skipping for region-of-interest (ROI) video coding. The techniques may be useful in video telephony (VT) applications such as video streaming and videoconferencing, and especially useful in low bit-rate wireless communication applications, such as mobile VT. The disclosed techniques analyze content information of a video frame to dynamically determine whether to skip a non-ROI area within the frame. For example, the skipping determination may be based on content activity, such as ROI shape deformation, ROI motion, non-ROI motion, non-ROI texture complexity, and accumulated distortion due to non-ROI skipping. The skip determination may operate in conjunction with either frame-level or macroblock-level bit allocation.

Abstract: The disclosure is directed to adaptive frame skipping techniques for rate controlled video encoding of a video sequence. According to the disclosed techniques, an encoder performs frame skipping in an intelligent manner that can improve video quality of the encoded sequence relative to encoding using conventional frame skipping. In particular, the disclosed frame skipping scheme is adaptive and considers motion activity of the video frames in order to identify certain frames that can be skipped without sacrificing significant video quality. The described frame skipping techniques may take into account the tradeoff between spatial and temporal quality of different video frames. In this manner, the techniques can allocate limited resources between the spatial and temporal quality in a way that can improve the visual appearance of a video sequence.

Abstract: The disclosed embodiments provide a method and apparatus for interoperability between CTX and DTX communications systems during transmissions of silence or background noise [FIG. 2]. Continuous eighth rate encoded noise frames are translated to discontinuous SID frames for transmission to DTX systems (402–410). Discontinuous SID frames are translated to continuous eighth rate encoded noise frames for decoding by a CTX system (602–606).

Abstract: An adaptive Intra-refresh (IR) technique for digital video encoding adjusts IR rate based on video content, or a combination of video content and channel condition. The IR rate may be applied at the frame level or macroblock (MB) level. At the frame level, the IR rate specifies the percentage of MBs to be Intra-coded within the frame. At the MB level, the IR rate defines a statistical probability that a particular MB is to be Intra-coded. The IR rate is adjusted in proportion to a combined metric that weighs estimated channel loss probability, frame-to-frame variation, and texture information. The IR rate can be determined using a close-form solution that requires relatively low implementation complexity. For example, such a close-form does not require iteration or an exhaustive search. In addition, the IR rate can be determined from parameters that are available before motion estimation and compensation are performed.

Abstract: A video demultiplexer and video decoder include features for efficient video data recovery in the event of channel error. The demultiplexer detects a boundary between physical layer data units and adds boundary information to the bitstream produced by the demultiplexer. The demultiplexer produces adaptation layer data units, which are processed by the adaptation layer to produce an application layer bitstream. When the video decoder encounters an error in the bitstream, it uses the boundary information to limit the amount of data that must be concealed. In particular, the boundary information permits the error to be associated with a small segment of data. The video decoder conceals data from the beginning of the segment of data, rather than an entire slice or frame in which the segment resides. In this manner, the video decoder provides efficient data recovery, limiting the loss of useful data that otherwise would be purposely discarded for concealment purposes.

Abstract: The disclosure is directed to techniques for encoder-assisted adaptive interpolation of video frames. According to the disclosed techniques, an encoder generates information to assist a decoder in interpolation of a skipped video frame, i.e., an S frame. The information permits the decoder to reduce visual artifacts in the interpolated frame and thereby achieve improved visual quality. The information may include interpolation equation labels that identify selected interpolation equations to be used by the decoder for individual video blocks. As an option, to conserve bandwidth, the equation labels may be transmitted for only selected video blocks that meet a criterion for encoder-assisted interpolation. Other video blocks without equation labels may be interpolated according to a default interpolation technique.

Abstract: The disclosure is directed to a video slicing technique that promotes low complexity, bandwidth efficiency and error resiliency. A video encoder places an RM close to the beginning of each logical transmission unit (LTU) so that all but a very small end segment of each video slice fits substantially within an LTU. Instead of requiring placement of RMs exactly at the LTU boundaries, a video encoder applies an approximate alignment technique. Video slices are encoded so that RMs are placed close to the beginning of each LTU, e.g., at the end of the first MB falling within the LTU. A portion of the last MB from the preceding slice carries over into the next LTU. Loss of an LTU results in loss of virtually the entire current slice plus a very small portion of the previous slice.

Abstract: Methods and apparatus are presented for supporting the transmission of variable-rate vocoder frames over non-compatible communication channels. Variable-rate vocoder frames are re-formatted as cargo in multi-rate vocoder frames. At the receiver, a determination is made as to whether a received multi-rate vocoder frame carries a variable-rate vocoder frame cargo. If a variable-rate vocoder frame is cargo, then a determination of the frame type is made. Various embodiments for conveying cargo information are presented.

Abstract: Methods and apparatus are presented for reducing the computational complexity of coding mode decisions by exploiting the correlations across spatially and/or temporally close coding mode decisions. A mode decision for a current macroblock is based on the mode decisions of spatially and/or temporarily close macroblocks.

Abstract: Methods and apparatus are presented herein to perform selective and/or scalable complexity control of the video codec, so that the amount of processing resources consumed by a video codec may be increased or reduced. Based on the configurable thresholds set within complexity control algorithms, the nonpredictive and the predictive coding sections of the video codec may be selectively implemented. The configurable thresholds are used to determine whether a desired amount of spatial information, such as texture information or motion information, is present within a video frame.

Abstract: A system and method for detection of rate determination algorithm errors in variable rate communications system receivers. The disclosed embodiments prevent rate determination algorithm errors from causing audible artifacts such as screeches or beeps. The disclosed system and method detects frames with incorrectly determined data rates and performs frame erasure processing and/or memory state clean up to prevent propagation of distortion across multiple frames. Frames with incorrectly determined data rates are detected by checking illegal rate transitions, reserved bits, validating unused filter type bit combinations and analyzing relationships between fixed code-book gains and linear prediction coefficient gains.

Abstract: The disclosed embodiments provide a method and apparatus for interoperability between CTX and DTX communications systems during transmissions of silence or background noise [FIG. 2]. Continuous eighth rate encoded noise frames are translated to discontinuous SID frames for transmission to DTX systems (402-410). Discontinuous SID frames are translated to continuous eighth rate encoded noise frames for decoding by a CTX system (602-606).

Abstract: Methods and apparatus are presented for reducing the number of bits needed to represent an excitation waveform. An acoustic signal in an analysis frame is analyzed to determine whether it is a band-limited signal. A sub-sampled sparse codebook is used to generate the excitation waveform if the acoustic signal is a band-limited signal. The sub-sampled sparse codebook is generated by decimating permissible pulse locations from the codebook track in accordance with the frequency characteristic of the acoustic signal.

Abstract: The disclosed embodiments provide a method and apparatus for interoperability between CTX and DTX communications systems during transmissions of silence or background noise. Continuous eighth rate encoded noise frames are translated to discontinuous SID frames for transmission to DTX systems. Discontinuous SID frames are translated to continuous eighth rate encoded noise frames for decoding by a CTX system.

Abstract: A call setup procedure is presented to permit vocoder bypass, which will allow the transmission of wideband speech packets between wideband terminals over narrowband transmission constraints. In addition, methods and apparatus are presented that allow the conversion between a wideband tandem-free operation, a narrowband tandem-free operation, and a standard tandem operation.

Abstract: The disclosed embodiments provide a method and apparatus for interoperability between CTX and DTX communications systems during transmissions of silence or background noise. Continuous eighth rate encoded noise frames are translated to discontinuous SID frames for transmission to DTX systems. Discontinuous SID frames are translated to continuous eighth rate encoded noise frames for decoding by a CTX system.