Abstract: A method and apparatus for producing a variable bit rate audio signal is disclosed. An audio signal is encoded into a plurality of encoded audio signals at different bit rates. A variable bit rate audio signal is produced by selecting between the plurality of encoded audio frames of different bit rates in accordance with a selection criterion.

Abstract: A method and apparatus for producing a variable bit rate audio signal is disclosed. An audio signal is encoded into a plurality of encoded audio signals at different bit rates. A variable bit rate audio signal is produced by selecting between the plurality of encoded audio frames of different bit rates in accordance with a selection criterion.

Abstract: A method and apparatus for producing a variable bit rate audio signal is disclosed. An audio signal is encoded into a plurality of encoded audio signals at different bit rates. A variable bit rate audio signal is produced by selecting between the plurality of encoded audio frames of different bit rates in accordance with a selection criterion.

Abstract: A system and method of evaluating a decoder under test can include the steps of storing a first segment of a video sequence for creating a first test frame portion including a first image, storing a second segment of video sequence for creating a second test frame portion including a second image, combining the first and second test frame portions into a visualization segment, streaming the visualization segment to the decoder, displaying the resultant output stream from the decoder under test, and determining if a defect exists in the displayed decoded output stream. Determining if a defect exists can include: if the display of the displayed visualization segment shows a steady picture, then determining there is a defect in the decoded picture, and if the display of the visualization segment shows flickering or flashing detail, then determining that there is a defect in the decoded picture.

Abstract: A method and apparatus for analyzing and monitoring packet streams in “real time”. The packet analyzer comprises an input buffer, a real-time analysis unit, a non-real-time analysis unit, a graphics unit, a monitor and a flushing circuit. A packet stream is received into the input buffer where the data is either read by the real-time analysis unit or flushed by the flushing circuit. Messages are passed between the real-time analysis unit and the non-real-time analysis unit to report on detected errors or to update packet stream information. In turn, real time packet stream information are displayed and updated on a display via the graphic unit. A method of detecting framing errors in a packet stream is incorporated by setting a 9th bit in the input buffer for each byte of data in a packet.

Abstract: A method of testing a decoder of a coded bitstream utilizes a test bitstream, containing in part embedded reference data, that is applied to a decoder being tested to produce a test result image that evidences whether or not the decoder correctly or incorrectly decodes the test bitstream. In an MPEG or an MPEG-like coding, for example, the test bitstream comprises a sequence of pictures representing at least one reference image portion, wherein at least one picture of the sequence of pictures typically is an intra-coded representation of the reference image portion and subsequent pictures of the sequence of pictures include an intra-coded representation of the reference image portion and a predictively coded representation of the reference image portion.

Abstract: A method and apparatus for adjusting an embedded portion of a television signal. The embedded portion is adjusted such that a downstream receiver effects no change on a displayed video upon decoding the adjusted embedded portion.

Abstract: An apparatus and concomitant method for creating and applying an encoded bitstream to evaluate the performance of a black box video decoder. The encoded bitstreams are designed such that the results from the DUT can be evaluated without the need of a human observer. The method applies the encoded bitstream to both a DUT and a compliant reference decoder and compares the results from both decoders to determine compliance of the DUT. Additional embodiments address postprocessing and the selection of a subset of test frames for evaluation.

Abstract: A method and apparatus for analyzing and monitoring packet streams in “real time”. The packet analyzer comprises an input buffer, a real-time analysis unit, a non-real-time analysis unit, a graphics unit, a monitor and a flushing circuit. A packet stream is received into the input buffer where the data is either read by the real-time analysis unit or flushed by the flushing circuit. Messages are passed between the real-time analysis unit and the non-real-time analysis unit to report on detected errors or to update packet stream information. In turn, real time packet stream information are displayed and updated on a display via the graphic unit. A method of detecting framing errors in a packet stream is incorporated by setting a 9th bit in the input buffer for each byte of data in a packet.

Abstract: A method and apparatus for analyzing and monitoring packet streams in “real time”. The packet analyzer comprises an input buffer, a real-time analysis unit, a non-real-time analysis unit, a graphics unit, a monitor and a flushing circuit. A packet stream is received into the input buffer where the data is either read by the real-time analysis unit or flushed by the flushing circuit. Messages are passed between the real-time analysis unit and the non-real-time analysis unit to report on detected errors or to update packet stream information. In turn, real time packet stream information are displayed and updated on a display via the graphic unit. A method of detecting framing errors in a packet stream is incorporated by setting a 9th bit in the input buffer for each byte of data in a packet.

Abstract: A method and apparatus for pre-processing an image sequence to extract side information concerning the image sequence is disclosed. In one embodiment, the side information is inserted into the image sequence, such that upon being encoded at a later time, the encoder can utilize the side information to best select one or more coding parameters. Alternatively, the side information can be stored on a storage device and is then made available to an encoder that is tasked with encoding the image sequence.

Abstract: Compressed bitstreams are characterized by generated graphical displays that display useful information related, for example, to the quality of the data contained in the bitstream. One set of graphical displays indicates lead time between receipt of packetized data and the corresponding decode or presentation time-stamp. Another set of bar graphical displays provides information related to bits per picture by (A) indicating fractions of useful bits versus zero-stuffing bits per picture, (B) distinguishing field pictures from frame pictures, and (C) plotting bars as a function of presentation or decode time rather than picture number to indicate the presence of 3:2 pulldown frame structure in the bitstream. Yet another set of graphical displays corresponds to coefficient/quantization (C/Q) diagrams that plot combinations of quantization level and number of non-zero quantized coefficients for sets of picture blocks.

Abstract: A method and apparatus for pre-processing an image sequence to extract side information concerning the image sequence. In one embodiment, the side information is inserted into the image sequence, such that upon being encoded at a later time, the encoder can utilize the side information to best select one or more coding parameters. Alternatively, the side information can be stored on a storage device and is then made available to an encoder that is tasked with encoding the image sequence.

Abstract: A method and apparatus for creating and using an encoded bitstream to evaluate a video decoder. The bitstream contains a sequence of pictures or frames such that when a video decoder decodes the bitstream correctly, a desired visible pattern is produced on a video display. Specifically, various display parameters or flags are varied in the bitstream to test the video decoder's ability to implement display features such as "3:2 pulldown". For example, the bitstream is capable of demonstrating incorrect decoding of the top.sub.-- field.sub.-- first and repeat.sub.-- first.sub.-- field flags by a MPEG compliant video decoder.

Abstract: A method and apparatus for adjusting the parameters of a PLL in a communication system. The method measures the rate of transmission of clock reference information by measuring the time of arrival of successive clock references or the difference of the clock reference values. The method applies the measured transmission rate to a plurality of predefined transmission rate ranges to acquire the proper gain factor values. These gain factor values are used to control the responsiveness of the PLL to new clock reference information.