摘要:
An agent manages multipath communications between a first network and a second network. The first network and a second network are wirelessly coupled by links through a plurality of wireless cellular devices. A link status monitor maintains a list of wireless cellular devices with bridging capability available for multipath communications between the first and second networks. A packet scheduler identifies segments of received packets originating from the second network and assigns one or more wireless cellular devices selected from the list to the identified segments. A packet transmitter encapsulates the segments of packets so identified and addresses the encapsulated segments to the assigned wireless cellular devices.
摘要:
Both live and offline transcoding of media is managed for storage in a cache. Requests for media are made by a client on a network and media taken from the cache and transcoded for delivery to the client. Media is also transcoded and stored in memory during idle request in anticipation of future requests during idle transcoder time between client requests. A prioritizer manages at least offline transcoding requests. A high priority queue operates at a higher priority than the low priority queue. The high priority queue receives live transcoding requests from a client on the network. A low priority queue receives offline transcoding requests. A media transcoder primarily transcodes media in accordance with requests from the high priority queue for delivery to a client on the network and then secondarily transcodes media in accordance with requests from the low priority queue when the high priority queue is empty. According to alternative embodiments the media transcoder transcodes media into segments and to modify frames when necessary to insure that they are decodable without accessing other segments.
摘要:
An advanced multiplexer designed and optimized for next generation on-demand video distribution is described. Features and capabilities include auto-discovery, channel-staggering and compatibility with static Virtual Channel Tables (VCTs). The multiplexer system facilitates auto-discovery by inserting identifiers into MPTSs (Multi-Program Transport Streams). These identifiers are echoed back to the multiplexer by the client set-top thereby indicating correspondence between modulators, service groups, and clients. When modulating multiple channels, FEC frames (Forward Error Correction frames) are staggered across channels to reduce correlation and clipping in the IFFT processor.
摘要:
A compressed video playback system which eliminates playback mode transition artifacts. Transitions between various playback modes are effected in such a manner that transition artifacts are eliminated by delaying playback mode transitions until appropriate frames of data are detected for propagation to the compressed video decoder. In addition, compressed video data retrieval methods are improved for supporting multi-speed playback modes in both forward and reverse directions in an optimal manner.
摘要:
A method and apparatus for reducing the size of data rate fluctuations that occur in forming a multiplex of a set of program streams, each program stream in said set being decodeable by a corresponding decoder, each corresponding decoder including a corresponding decoder buffer, said decoder buffers having a maximum allowable size, said method comprising varying the formation of the different program streams in said set to minimize the memory requirement of the decoder buffers. In one embodiment, for the case of the streams being segments of a program, varying includes varying the segment length. In another embodiment, varying includes adjusting the relative alignment of the program streams. Different embodiments of adjusting include inserting program material such as a pause at selected points in time, causing decoder buffers to underflow at selected points in time, and varying the rate of decoding and display at selected points in time.
摘要:
Virtually random and on-demand access is provided to a virtually unlimited number of subscribers by partitioning the video program into an ordered sequence of n segments and providing the subscribers concurrent access to each of the n subsequences. A data stream representative of the video program is partitioned into n subsequences, each representative of one of the n segments. The data of each of the n subsequences is organized as an ordered sequence of elements. The elements of each of the n subsequences are interleaved and the interleaved data stream is continuously transmitted over a video program distribution medium at a rate which renders the data representing each segment concurrently available to any subscriber having a receiver capable of selecting, assembling, and displaying the data of a particular segment. The data stream can be compressed prior to interleaving using one of many known video data compression standards and techniques. Data compression can be performed in real time, or iteratively using software. The interleaved data stream can be transmitted in real time, or it can be stored on a storage device such as a hard disk or optical disk for later retrieval and transmission. The interleaved data stream can be ordered using any known standard by which video data is transmitted for reconstruction and display by a receiver. Data can be inserted into the interleaved data stream to inform the receiver to which of the n segments a portion of the interleaved data stream belongs, as well as the encoding level necessary for decompression of the data and time stamps to indicate order of display.
摘要:
A multiple serial access memory which includes a dynamic random access memory array is disclosed. The array is randomly addressed to input blocks of data. Address signals are provided to the array to output rows of data. A plurality of serial output ports are coupled to the output of the array for selectively latching different rows of data output from the array. The serial output ports are clocked to output the latched data therefrom. In an illustrated embodiment, each of the serial output ports contains a shift register having a length equal to the width of the memory array. The shift register is responsive to a first timing signal for latching a row of data from the array. A second timing signal actuates the shift register to shift a row of latched data. The serial access selector coupled to the shift register outputs a selected portion of the shifted data from the serial output port. The serial access memory has particular application as the frame store for a motion compensated interframe image coding/decoding system.
摘要:
Digital video signals are processed by a plurality of independently operating processors to provide data for transmission in a compressed, motion compensated form. A video image frame area is divided into a set of subframes. The set of subframes is systematically shifted such that the individual subframes progressively cycle across and wrap around the video image frame area. For each successive video frame, video image data bounded by each of the different subframes is independently compressed using motion estimation to reduce data redundancy among the successive frames. The motion estimation is limited for each subframe of a current video frame to areas of a previous video frame that were bounded by the same subframe in the previous frame. In an illustrated embodiment, the set of subframes is shifted once for each successive video frame, and each subframe includes a refresh region whereby the video image frame area is progressively refreshed as the subframes are shifted thereacross. Receiver apparatus for use in decoding the independently processed subframe data is also disclosed.
摘要:
Methods are provided for inserting advertisements or the like and/or to perform grooming functions for a video, audio and/or data stream. Video programming is received in a network stream. Alternate content, such as advertisements, is received in content stream. The content stream is preconditioned to provide an entrance point therein for splicing the network stream to the content stream. Preconditioning of the content stream can also be performed to provide an exit point for splicing back to the network stream when the alternate content (e.g., advertisements) has concluded.
摘要:
The present invention provides a balanced video distribution system, as well as corresponding methods and apparatus, which utilize feedback from the channel multiplexers as well as rate estimation and predictive rate control. Packets of a video stream are received at an input buffer. A transmission deadline is determined for the packets. A fullness level of the input buffer is also determined. A future time at which said packets can be transmitted may be estimated based on the buffer fullness level. A bit rate of the video stream can be adjusted based on the estimated future time and the transmission deadline. For example, the bit rate may be adjusted in proportion to a difference between the estimated future time and the transmission deadline.