Abstract: A method for splicing MPEG-2 encoded transport streams to prevent decoder buffer underflow. Emulation of the transport stream prior to transmission determines whether a decoder underflow would occur after a splice proposed at a predetermined time. When a potential underflow is determined for a decoder buffer, null packets are deleted prior to the time proposed for transmission for the splice, and an earlier splice time is recomputed. A time delay is added to presentation time stamp and the decoding time stamp. A relationship between the respective components involved is described to calculate the null packets to be deleted as well as to calculate the time delay to be added to a presentation time stamp and to a decoding time stamp, whereby decoder buffer underflow is prevented.

Abstract: A splicing system includes a splicer for seamlessly splicing togther digitally encoded data streams. In a preferred embodiment, the splicer preferably parses successive splice buffers of data stream data for a splice-out point and a splice-in point, closing an initial group of pictures GOP if needed. The preferred splicer further finds a new data stream real-time program clock reference PCR value for aligning new data stream decode/presentation, and aligns the new data stream start time. Concurrently, the splicer preferably uses a frame table to detect overflow and corrects such overflow by adding null packets, thereby delaying portions of data stream data. The splicer also preferably restores data stream encoding by deleting null packets, and thereby accelerating a portion of data stream data. In a further preferred embodiment, the splicer preferably uses a bit-clock schedule offset to delay or accelerate portions of data stream data.

Abstract: A method of performing the multiplexing of data streams in a packet network by initializing the address pointers in an output queue to point to their own addresses. Then, select a data packet from an input queue and determine whether the preferred location for its pointer in the output queue is occupied. If that location is occupied, go to the address pointed to by the address pointer for that location, and if not occupied, store the pointer to the input stream data in that location.

Abstract: Using the method of the present invention, clock mismatch or drift between a packet network transmitter and receiver can be compensated for via receiver clock rate change or bit rate change. The method includes estimating the average receiver FIFO buffer memory level over time, changing the packet network receiver bit rate or clock rate according to the average receiver FIFO buffer memory level change while still satisfying the MPEG-2 system specification.

Abstract: A method of PROTO implementation in MPEG-4 is provided, including the steps of: defining a PROTO object class, instantiating a PROTO object, calling the PROTO object into an MPEG-4 scene graph, and rendering the PROTO object.

Abstract: A method and system are presented for producing an audio/video stream with improved video quality for a given bitrate, using non-standard sampling rates while preserving timely playback by the decoder. The method may include sub-sampling according to a duty cycle and/or time-slapping frames in an audio/visual stream.

Abstract: In a combined audio and video encoding system, the encoding system receiving a stream of video samples and a stream of audio samples, the encoding system producing an encoded video stream from the video samples and an encoded audio stream from the audio samples, a method for synchronizing between the encoded video stream and the encoded audio stream, the method including the steps of monitoring the encoded video stream and the encoded audio stream, detecting the amount of video data accumulated from the encoded video stream in a given time period, detecting the amount of audio data accumulated from the encoded audio stream in a given time period, increasing the number of audio samples in the audio stream, when the accumulated amount of video data is greater than the accumulated amount of audio data and decreasing the number of audio samples in the audio stream, when the accumulated amount of audio data is greater than the accumulated amount of video data.

Abstract: The present invention provides a method and a system which provide a plurality of compressed presentations for each frame of the original video signal, each presentation provided according to a different bit-rate, wherein the transmitting system selects from the compressed presentations a presentation, which is most suitable for the bit-rate, currently available over the transmission line and transmits it.