专利快速检索-快速检索全球专利，免费商用专利数据库-IPRDB

61. 发明公开

EP0980186A2 Method and apparatus for managing a decoder buffer 审中-公开
标题翻译： Verfahren und Vorrichtung zur Verwaltung eines Decoder-Pufferspeichers
公开(公告)号：EP0980186A2
公开(公告)日：2000-02-16
申请号：EP99202518.9
申请日：1999-08-02
申请人： NDS LIMITED
发明人： Davies, Colin, Dr. , Huggett, Anthony R. , Stubbings, Clive A., Dr. , Funnell, John S. , Murray, Kevin A. , Warburton, Richard J.
IPC分类号： H04N7/58 , H04N7/24
CPC分类号： H04N21/2365 , H04N21/23611 , H04N21/2401
摘要： The present invention relates to digital data transmission and more precisely a method and apparatus for managing a decoder buffer.
In data transmission applications, such as digital video broadcasting, large amounts of data are encoded and transmitted to decoders having a decoder buffer. Management of the decoder buffer is very important as transmittal of too little data can result in the decoder buffer underflowing (becoming empty), or if too much data is transmitted the decoder buffer could overflow. Both decoder buffer overflow and underflow result in loss of data and the decoding process is adversely affected.
The present invention provides a method and apparatus for managing a decoder buffer such that decoder buffer overflow and underflow are minimised.
摘要翻译：本发明涉及数字数据传输，更准确地说，涉及一种用于管理解码器缓冲器的方法和装置。在诸如数字视频广播的数据传输应用中，大量数据被编码并传送到具有解码器缓冲器的解码器。解码器缓冲器的管理非常重要，因为传输太少的数据可能导致解码器缓冲器下溢（变空），或者如果发送的数据太多，则解码器缓冲器可能溢出。解码器缓冲区溢出和下溢均导致数据丢失，解码过程受到不利影响。本发明提供一种用于管理解码器缓冲器的方法和装置，使得解码器缓冲器溢出和下溢最小化。

62. 发明公开

EP0973290A2 Statistical data multiplexing 审中-公开
标题翻译：统计数据分组
公开(公告)号：EP0973290A2
公开(公告)日：2000-01-19
申请号：EP99202208.7
申请日：1999-07-06
申请人： NDS Limited
发明人： Budge, Michael
IPC分类号： H04J3/24 , H04N7/52
CPC分类号： H04N21/4347 , H04B7/18513 , H04J3/247 , H04N21/235 , H04N21/23614 , H04N21/2365 , H04N21/23655 , H04N21/4348 , H04N21/435
摘要： The invention relates to multiplexing data packets in a data service channel with data in one or more digital video signal channels to form a multiplexed output signal. The data in the data service channel may include control data, conditional access data, electronic program guides, paged data services, service information, broadcast internet information, and business information such as financial share information.
The data packets each comprise a time stamp indicating a requested delivery time and the data packets are sorted into a queue in time stamp order. The urgency of the data service channel is calculated as a function of the queue length and requested delivery times. The share of the bit rate of the multiplexed output signal allocated to the data service channel is varied according to its urgency. An error value is calculated for each data packet to represent the error between the expected delivery time and the requested delivery time to the head of the queue and the urgency of the data channel is derived as an average of the error values. The average may be a weighted average.
摘要翻译：本发明涉及将数据业务信道中的数据分组与一个或多个数字视频信号信道中的数据进行复用以形成复用的输出信号。数据服务信道中的数据可以包括控制数据，条件访问数据，电子节目指南，分页数据服务，服务信息，广播互联网信息以及诸如财务共享信息的商业信息。数据分组各自包括指示所请求的传递时间的时间戳，并且数据分组按时间戳顺序排列成队列。根据队列长度和请求的交货时间计算数据服务通道的紧急性。分配给数据业务信道的复用输出信号的比特率的份额根据其紧急度而变化。为每个数据包计算出一个错误值，以表示预期传送时间与向队列头部发出的请求传送时间之间的误差，数据通道的紧急度被导出为误差值的平均值。平均值可以是加权平均值。

63. 发明公开

EP0957602A3 Multiplexer 审中-公开
标题翻译：复用器
公开(公告)号：EP0957602A3
公开(公告)日：1999-12-08
申请号：EP99201180.9
申请日：1999-04-16
申请人： NDS LIMITED
发明人： Nagy, Darrin
IPC分类号： H04J3/06 , H04L12/56 , H04L29/06
CPC分类号： H04N21/236
摘要： A method of scheduling data packets in a multiplexer, particularly in an MPEG-2 server, the method comprising the steps of combining a number of packet flows to provide a smaller number of flow queues, and operating a scheduling algorithm on the flow queues to select a packet to be output. The method may also include the step of generating tokens representing the packets and the flow queues may then contain the tokens and not the packets.
摘要翻译：一种在多路复用器中，特别是在MPEG-2服务器中调度数据分组的方法，该方法包括以下步骤：组合多个分组流以提供较少数量的流队列，并且在流队列上操作调度算法以选择要输出的数据包。该方法还可以包括生成表示分组的令牌的步骤，并且流队列可以然后包含令牌而不是分组。

64. 发明公开

EP0948205A2 A method and apparatus for processing compressed video data streams 有权
标题翻译： Verfahren und Vorrichtung zur Verarbeitung von komprimiertenVideodatenströmen
公开(公告)号：EP0948205A2
公开(公告)日：1999-10-06
申请号：EP99200599.1
申请日：1999-03-03
申请人： NDS LIMITED
发明人： Bock, Alois Martin , Jordan, John Paul
IPC分类号： H04N7/24
CPC分类号： H04N21/23424 , G06T9/004
摘要： The present invention relates to the field of digital broadcasting, and more particularly the insertion of digital video streams into other digital video streams.
Compressed digital video streams, such as those compressed using the common MPEG-2 system, use a sequence of frames to compress a video sequence. Part of the encoding method to compress frames involves making predictions based on past or future frames.
Where part of a compressed video stream is to be inserted into another existing video stream, problems may arise at the insertion point due to dependencies on past or future frames which occur outside of the insertion point. The effect of this is that the decoding process lacks information on which to make its predictions, and this could cause a decoder to reset or display frames out of order.
The present invention overcomes this problem in a way which allows frame accurate insertion to be achieved without compromising quality.
The present invention can be used to pre-process a compressed video stream ready for insertion, or can be used to dynamically insert a compressed video stream into an existing compressed video stream.
摘要翻译：本发明涉及数字广播领域，更具体地说，涉及将数字视频流插入到其他数字视频流中。压缩的数字视频流，例如使用通用MPEG-2系统压缩的数字视频流，使用一系列帧来压缩视频序列。压缩帧的编码方法的一部分涉及根据过去或将来的帧进行预测。当压缩视频流的一部分被插入到另一现有视频流中时，由于依赖于发生在插入点之外的过去或未来帧，插入点可能会出现问题。这样做的结果是解码过程缺少关于哪个进行预测的信息，并且这可能导致解码器重新排列或者显示帧不正常。本发明克服了这个问题，可以在不影响质量的情况下实现帧精确插入。本发明可以用于预处理准备插入的压缩视频流，或者可以用于将压缩视频流动态地插入到现有的压缩视频流中。

65. 发明公开

EP0942602A2 Method and apparatus for estimating the difference in picture quality between a distorted and an undistorted video signal 审中-公开
标题翻译：一种用于在扰动之间的图像质量的差的估计方法和装置以及不受干扰的视频信号
公开(公告)号：EP0942602A2
公开(公告)日：1999-09-15
申请号：EP99200314.5
申请日：1999-02-03
申请人： NDS LIMITED
发明人： Bock, Alois Martin
IPC分类号： H04N7/24
CPC分类号： H04N19/60 , H04N17/004
摘要： The invention relates to estimating the difference in picture quality between two versions of a video signal, one of which has been subject to distortion and the other of which has not been subject to the distortion. The invention has application to estimating the picture quality of a signal subjected to digital compression in comparison to the picture quality of the signal before compression.
The estimate of picture quality is obtained by first deriving a difference signal representing the difference between the distorted and undistorted versions of the video signal. A masking signal is obtained by filtering the undistorted version of the video signal and is used to mask the difference signal thereby to derive an output measure of the said difference in picture quality. The masking signal is obtained by filtering the undistorted version of the video signal through a channel including a high-pass edge detection filter.
Preferably, a second measure of the difference in picture quality is obtained by applying both the distorted and undistorted versions of the video signal to a circuit that detects block distortion across block boundaries. The output from the block distortion circuit is also masked by the masking signal.
摘要翻译：本发明涉及估计视频信号的两个版本，其中一个一直受到失真，另一种处理不当的是经历失真之间的图像质量的差异。本发明已经应用到估计相比于压缩前的信号的画面质量进行数字压缩的信号的画面质量。画面质量的估计是通过首先导出表示所述视频信号的失真和非失真版本之间的差的差信号而得到。掩蔽信号是通过过滤的视频信号的未失真的版本获得，并且被用来进行掩蔽差信号在图像质量的所述差值的输出度量来导出。掩蔽信号是由通过一信道包含一个高通边缘检测滤波器滤波的视频信号的未失真的版本得到。优选地，在图像质量差的第二项措施是通过跨块边界施加这两个视频信号的失真和非失真版在电路没有检测到数据块失真得到。从数据块失真电路的输出因此被掩蔽信号掩蔽。

66. 发明公开

EP0940043A1 METHOD AND APPARATUS FOR MODIFYING TABLES OF DATA 失效
标题翻译：方法和设备变化数据表
公开(公告)号：EP0940043A1
公开(公告)日：1999-09-08
申请号：EP97912358.0
申请日：1997-11-14
申请人： NDS LIMITED
发明人： CARTWRIGHT, Charles , WILSON, Giles, Flat 3 , CAINES, Christopher
IPC分类号： H04N7
CPC分类号： H04N21/4347 , H04N21/2365
摘要： The present invention concerns a method and apparatus for modifying tables of data included in a digital stream of encoded data. The invention is of particular application to modifying the data in tables of data included in the digital transport stream of a digitally compressed television signal. The tables of data are extracted from the stream and the extracted tables are processed to identify data that are to be dropped. A filter is used to filter out the identified data and new local data is entered into the extracted tables to replace dropped data and thereby form modified tables of data. The filtered stream is multiplexed with the modified tables of data to form an output digital stream. By this means, the constantly updated tables in the input stream are modified only in respect of the local changes and the updates are passed through to the output stream.

67. 发明公开

EP0858184A3 Digital recording protection system 失效
标题翻译：系统保护数字记录
公开(公告)号：EP0858184A3
公开(公告)日：1999-09-01
申请号：EP98300596.8
申请日：1998-01-28
申请人： NDS LIMITED
发明人： Tsuria, Yossef
IPC分类号： H04L9/00 , H04N5/76
CPC分类号： H04N21/4135 , H04N5/913 , H04N5/926 , H04N7/163 , H04N7/1675 , H04N21/4325 , H04N21/4408 , H04N21/4623 , H04N2005/91364
摘要： A system for producing an output scrambled digital data stream from an input scrambled digital data stream. The input scrambled digital data stream includes a plurality of control messages (ECMs), each ECM including coded information for generating a control word (CW) associated with the ECM and being encoded using an ECM key. The input scrambled digital data stream also includes a plurality of segments of scrambled digital data, each segment of scrambled digital data being associated with one of the plurality of ECMs and being scrambled using the CW associated with the ECM. A method for producing the output scrambled digital data stream includes replacing each of the plurality of ECMs with a corresponding transformed ECM (TECM) each corresponding TECM comprising coded information for generating the CW associated with the corresponding ECM and being encoded using a TECM key, thus producing the output scrambled digital data stream, wherein the ECM key is replaced with a new ECM key at an ECM key change time, and the TECM key is not replaced at the ECM key change time.

68. 发明公开

EP0912065A2 Method and apparatus for re-timing a digital signal 审中-公开
标题翻译： Verfahren und Vorrichtung zur Resynchronisierung eines digitalen Signals
公开(公告)号：EP0912065A2
公开(公告)日：1999-04-28
申请号：EP98118795.8
申请日：1998-10-05
申请人： NDS LIMITED
发明人： Loverseed, Edwin
IPC分类号： H04N7/62
CPC分类号： H04N21/242 , H04J3/0632 , H04L2012/5616 , H04L2012/5652 , H04L2012/5674 , H04N21/23406 , H04N21/4305 , H04N21/44004 , H04N21/64307 , H04Q11/0478
摘要： The present invention relates generally to receiving digital signals and more specifically to a method and apparatus for re-timing digital signals. The invention is of particular use in the field of digital video broadcasting.
This invention provides a method of receiving a digital signal made up of one or more packets which has been transmitted over a channel. An indicator is applied to each packet of the digital signal. The indicator is characteristic of the relative position of each packet with respect to time. The digital signal is output by releasing each packet when the indicator reaches a predetermined value. The packets can be released in such a manner that any timing errors in the received signal relative to an original transmitted signal are removed.
摘要翻译：本发明一般涉及接收数字信号，更具体地说涉及用于对数字信号进行重新定时的方法和装置。本发明在数字视频广播领域中特别有用。本发明提供一种接收由已经通过信道发送的一个或多个分组组成的数字信号的方法。指示符应用于数字信号的每个数据包。该指标是每个包相对于时间的相对位置的特征。当指示符达到预定值时，通过释放每个数据包来输出数字信号。可以以这样的方式释放分组，使得相对于原始发送信号的接收信号中的任何定时误差被去除。

69. 发明公开

EP0906699A1 METHOD AND APPARATUS FOR PROCESSING A DIGITAL SIGNAL 失效
标题翻译：方法和装置处理的数字信号
公开(公告)号：EP0906699A1
公开(公告)日：1999-04-07
申请号：EP97924123.0
申请日：1997-05-29
申请人： NDS LIMITED
发明人： BOCK, Alois, Martin
IPC分类号： H04N7
CPC分类号： H04N21/23655 , H04N19/117 , H04N19/137 , H04N19/146 , H04N19/149 , H04N19/172 , H04N19/179 , H04N19/503 , H04N19/61 , H04N19/80 , H04N19/85
摘要： The present invention relates to a method and apparatus for analysing a digital video signal (20) preparatory to the digital compression encoding of the video signal. The signal (20) is applied to an analyser (22) to store samples of the video signal and to derive difference signals representing a number of parameters of the signal. One such parameter is the absolute difference between pixel samples of the signal which are adjacent in a vertical-temporal direction, i.e. the absolute difference between each sample and a sample one frame period later. Other parameters of the video signal are derived from absolute differences between the pixel samples taken over periods of one line, one field and one sample interval. A control signal representing the coding criticality of the input video signal is produced by accumulating the difference signals and combining them as a weighted sum. A low-pass filter in a pre-processor (21) has a bandwidth controlled by the control signal and filters the video signal (20) to remove or limit components which would result in coding artefacts in the signal after compression encoding. The control signal may also be fed to other components in the transmission chain, such as an encoder (23) and statistical multiplexer (24) to provide an early indication of picture criticality.

70. 发明公开

EP0891673A1 BUFFER CONTROL IN A CODED DATA TRANSMISSION SYSTEM 失效
标题翻译：编码数据传输系统中的缓冲器控制
公开(公告)号：EP0891673A1
公开(公告)日：1999-01-20
申请号：EP97915597.0
申请日：1997-04-04
申请人： NDS LIMITED
发明人： BUDGE, Michael, Richard, Joseph , JORDAN, John
IPC分类号： H04N7 , H04J3 , H04L13
CPC分类号： H04N21/23406 , H04N19/152 , H04N19/50 , H04N21/2365 , H04N21/23655 , H04N21/2401
摘要： According to one aspect of the present invention there is provided a method of changing the throughput of data in a digital data transmission system, comprising, monitoring the rate of data input to an encoder buffer to determine the decoder buffer requirements downstream; and controlling the encoder buffer in response to the monitoring step such that a change in the rate of data output from the encoder is lagged by a predetermined time period from any change in rate of data input to the encoder buffer. This predictive technique achieves the requirement of instantly changing bitrate in a seamless manner. A seamless bitrate change implies that there is no break in the decoding of the bitstream at the receiver, and also no abnormal artefacts at the receiver. Therefore to change bitrate seamlessly the receiver buffer should not be overflowed or underflowed, and the time stamp offset in the bitstream (the rate buffer delay) should remain constant so that the receiver need not gain or skip frames.
摘要翻译：根据本发明的一个方面，提供了一种改变数字数据传输系统中的数据吞吐量的方法，包括：监视输入到编码器缓冲器的数据速率以确定下游的解码器缓冲器需求; 以及响应于监视步骤控制编码器缓冲器，使得从编码器输出的数据的速率的变化滞后预定的时间段，从输入到编码器缓冲器的数据的速率的任何变化落后。这种预测技术实现了以无缝方式立即改变比特率的要求。无缝比特率变化意味着在接收器处对比特流的解码没有中断，并且在接收器处也没有异常假象。因此，为了无缝地改变比特率，接收缓冲器不应该被溢出或下溢，并且比特流中的时间戳偏移（速率缓冲器延迟）应当保持恒定，以便接收器不需要增益或跳过帧。

你已经成功收藏专利！

检索式保存成功!

IPRDB

热门服务

关于我们

友情链接

联系方式