Cisco Technology, Inc.

Cisco Systems Inc.

Compression Labs, Inc.

Compressions Labs, Inc.

Yi Tong Tse

Ke Shen

Michael J Healy

John T Chapman

Fang Wu

Ji Zhang

Sangeeta Ramakrishnan

Denis Downey

Bipin Todur

Smita Gupta

Xiaomei Liu

Yuen-Wen Lee

A system and related methodology are provided that are configured to receive, at a first network element, multiple channels of video delivered as respective streams of packets, form a packet switched communication frame including a sub-layer header, encapsulate packets from the multiple channels of video into a payload field of the communication frame to obtain encapsulated packets, identify the encapsulated packets in the payload field with respective tags in the sub-layer header, designate the encapsulated packets in the payload field with respective launch values in the sub-layer header, and transmit the communication frame to a second network element. The first network element may be a universal edge quadrature amplitude modulator (UEQAM) and the second network element may be a relatively distant fiber node of a cable plant. The sub-layer header may also include Program Clock Reference (PCR) offset data that can be used for PCR re-stamping.

Multi-channel MPEG between headend and fiber node

A system, and related methodology, are provided that are configured to receive, at a first network element such as a Universal Edge Quadrature Amplitude Modulator (UEQAM), multiple channels of data delivered as respective streams of packets, form a packet switched communication frame including a sub-layer header, encapsulate packets from the respective multiple channels into a payload field of the packet switched communication frame, identify the packets encapsulated in the payload field with respective tags in the sub-layer header, and transmit the packet switched communication frame to a second network element such as a Downstream Physical (DS-PHY) entity where the individual packets are recovered and mapped to selected respective stream processing resources based on respective tags.

Transmission of multi-channel MPEG

In one embodiment, a method is described that includes receiving a conditioned bitstream that includes a digital insertion location and primary network packets that contain compressed video data. The digital insertion location includes replaceable network packets. The method also includes receiving a second bitstream that includes replacement compressed video data. The method also includes determining a location of the digital insertion location. The method further includes adjusting the bitrate of the replacement compressed video data to create adjusted replacement compressed video data. The method further includes providing timestamp information with the replacement compressed video data. The method additionally includes packetizing the adjusted replacement compressed video data and timestamp information into replacement network packets. The method further includes combining the replacement network packets into the digital insertion location in the conditioned bitstream at the network packet level without depacketizing or decompressing the compressed video data in the primary network packets.

Expedited splicing of video streams

In one embodiment, a gateway between a variable delay network and a constant delay network receives over the variable delay network a plurality of data streams to be multiplexed over a modulated channel extending through the constant delay network. A first processing component of the gateway generates command-packet-descriptors corresponding to content packets included in the received data streams. A second processing component of the gateway uses transmit time indications included in the command-packet-descriptors to schedule transmission of modulated packets representing the received data streams over the modulated channel.

Intra channel video stream scheduling

According to the present invention, methods and apparatus for updating reduction ratios are provided. An input bit sequence can be altered to provide modified output bit sequence. The input bit sequence may represent information in a portion of data such as a video sequence, a picture, or an audio stream. In one example, the bit sequence is an MPEG-2 video sequence. The input bit sequence is altered using a reduction ratio to provide a modified output bit sequence. The reduction ratio can be continually updated using rate control information to achieve a target reduction ratio for the input bit sequence.

Methods and apparatus for updating a reduction ratio

A method and apparatus for clock recovery for constant bit rate MPEG-2 compliant single program transport stream and multiple program transport stream delivered over UDP/IP is disclosed. Clock recovery utilizes a dejittering filter to remove arrival time jitter from received packets and a phase lock loop is used to recover a PCR clock rate up to a range allowed by the MPEG-2 System specification. An MPEG-2 compliant output stream is produced, even when the input PCR does not meet the timing requirement specified by the MPEG-2 System specification.

Clock recovery algorithm for remultiplexing MPEG-2 SPTSs and/or MPTSs in the presence of network jitter

Techniques and mechanisms for performing error minimizing requantization are provided. Quantized coefficients associated with a bitstream are received. It is determined whether the quantized coefficients are associated with an inter macroblock or an intra macroblock. Inter macroblock and intra macroblock formulas minimizing requantization error are applied to determine requantized coefficients.

Methods and apparatus for minimizing requantization error

The present invention relates to systems and methods for efficient bit rate alteration of a bitstream to match an available channel capacity. The efficient bit rate alteration includes selective re-quantization of the compressed bitstream. Selective re-quantization according to the present invention applies multiple re-quantization schemes to different portions of a bitstream. In one embodiment, the multiple re-quantization schemes each have a different computational load. By selectively choosing which type of re-quantization is performed on each portion, efficient bandwidth scaling and data transmission may be achieved both when computational capacity is limited and when video data integrity is important.

Methods for efficient bandwidth scaling of compressed video data

According to the present invention, methods and apparatus for filtering transform coefficients are provided. Transform coefficients associated with an input bit sequence can be zeroed to provide modified transform coefficients associated with an output bit sequence. The transform coefficients may represent information in a portion of data such as a video frame, a picture, or an audio stream. In one example, the transform coefficients are DCT coefficients of an MPEG-2 video sequence. The transform coefficients are filtered to provide modified transform coefficients associated with an output bit sequence. The output bit sequence is a rescaled version of the input bit sequence.

Methods and apparatus for transform coefficient filtering

According to the present invention, methods and apparatus for performing error minimizing requantization are provided. Quantized coefficients associated with a bitstream are received. It is determined whether the quantized coefficients are associated with an inter macroblock or an intra macroblock. Inter macroblock and intra macroblock formulas minimizing requantization error are applied to determine requantized coefficients.

A system for performing frame accurate bitstream splicing includes a first pre-buffer, a second pre-buffer, a seamless splicer, and a post-buffer. The system also includes a time stamp extractor, a time stamp adjuster, and a time stamp replacer for timing correction. The first and second pre-buffers are input buffers to the seamless splicer, and the post-buffer is coupled to the output of the seamless splicer. The seamless splicer receives the two streams via the first and second pre-buffers and produces a single spliced bitstream at its output in response to the cue tone signal. The seamless splicer provides the first bitstream, then re-encodes portions of the first and second bit streams proximate the splicing points (both the exit point and the entry point), and then switches to providing a second bitstream. The seamless splicer also performs rate conversion on the second stream as necessary to ensure decoder buffer compliance for the spliced bitstream. The present invention also includes a method for performing bitstream splicing comprising the steps of: determining a splicing point switching between a first bitstream and a second bitstream, determining whether the second bitstream has the same bit rate as the first bitstream, converting the rate of the second bitstream if it is not the same as the bit rate of the first bitstream, and re-encoding picture proximate the splicing point.

System and method for frame accurate splicing of compressed bitstreams

A post-processor for a decoded video sequence includes a digital noise reduction unit and an artifact reduction unit which significantly reduce blocking artifacts and mosquito noise in a video image. The post-processor uses both temporal and edge characteristics of the video image to enhance the displayed image. A coding parameter from a decoder is used in a coding parameter adaptive filter unit within an artifact unit to further enhance the perceived quality of the displayed image. The coding parameter for a particular macroblock is selected using a characteristic of that macroblock. The post-processor operates on a current frame of pixel data using information from the immediately preceding post-processed frame that is stored in a frame memory of the post-processor. The post-processor uses artifact reduction only on portions of the image that are not part of an edge, and are not part of a texture or fine detail area. Since artifact reduction is not utilized on these areas, the post-processed image is not softened in regions where it is easily noticed by the human eye.

Coding parameter adaptive transform artifact reduction process

A post-processor for a decoded video sequence includes a digital noise reduction unit and an artifact reduction unit which significantly reduce blocking artifacts and mosquito noise in a video image. The post-processor uses both temporal and edge characteristics of the video image to enhance the displayed image. The post-processor operates on a current frame of pixel data using information from the immediately preceding post-processed frame that is stored in a frame memory of the post-processor. The post-processor first identifies texture and fine detail areas in the image. The post-processor uses artifact reduction only on portions of the image that are not part of an edge, and are not part of a texture or fine detail area. Since artifact reduction is not utilized on these areas, the post-processed image is not softened in regions where it is easily noticed by the human eye.

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San Jose, CA, United States of America

Yi Tong Tse