GB2428843A - Monitoring a plurality of channels - Google Patents

Abstract

A system for simultaneously monitoring for content a plurality of channels including Identifying Data, comprises: a multi-channel receiver module for receiving a plurality of multiplexed broadcast or transmitted channels; a distribution module for sending the received data stream corresponding to each channel in UDP/IP packet format to a unique port on a computer or network; a conversion module 22 for converting the data stream at a given port into a format suitable for decoding; a decoder module 32 for monitoring the data stream for said Identifying Data; and logging means 42 for storing the output of said decoder module including said Identifying Data and related information such as the identity of the channel involved and/or broadcast or transmission times. The system is very scaleable and flexible, and can provide simultaneous monitoring of tens or hundreds of channels at low cost.

Description

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SYSTEM AND METHOD FOR MONITORING A PLURALITY OF CHANNELS

[001] This invention relates to a system and method for monitoring a plurality of channels. It relates particularly, though not exclusively, to the monitoring of multiplexed broadcast or transmitted audio or video channels for the detection of airing of labelled content, and provides for the automated simultaneous monitoring of such content.

[002J There are many reasons to monitor the content of broadcast or transmitted signals. These include, but are not limited to, royalty collection, confirmation of the timely broadcast of content, the detection of unauthorised airing of content, and the tracking of content usage for marketing purposes.

[003] Known methods of monitoring broadcast content include manual methods in which a person views a television channel or listens to a radio station and notes details of the broadcast content. A disadvantage of such a method is that it is labour intensive (generally only one broadcast channel at a time may be monitored by a given person) and tedious for the person. Consequently, such monitoring is relatively expensive and the data recorded can be subject to human error.

[004] Other means involving the automatic monitoring of broadcasts are also known. Generally these rely on the detection of a segment of data, hereinafter referred to as Identifying Data' that identifies a specific piece of content, for example a music track or advertisement. Such Identifying Data could either be part or a characteristic of the actual data of the content in which case the Identifying Data is referred to by a person skilled in the art as a Fingerprint,' or the Identifying Data could be inserted into the content, usually by such means that the modified content is perceptually identical to,the original content, in which case such Identifying Data is referred to by a person skilled in the art as a watermark' [005] For example, US 5, 918,223 describe a fingerprint' based means for content based storage, analysis, retrieval and segmentation of audio information in which content is identified using statistical or frame by frame comparison.

[006] US 4,547,804 describes a method and apparatus for the automatic identification and verification of commercial broadcast programmes by the insertion, and subsequent detection, of an identifying code in each frame of the broadcast programme. The method involves the reception of a broadcast signal by an antenna or cable at a receiver station that is coupled to a switchable RF tuner by means of a pre-amplifier. The switchable RF tuner incorporates a video channel switch. The purpose of the video channel switch is to switch sequentially between a plurality of video channels to enable monitoring of a given channel for a predetermined interval during a predetermined period of time thus allowing monitoring of a plurality of video channels.

[007] A disadvantage of this approach is that the continuous monitoring of a given broadcast channel precludes the monitoring of other broadcast channels when using the same monitoring equipment. Furthermore, in order to detect the Identifying Data the broadcast channel must be monitored for a minimum period of time to ensure that at least one set of Identifying Data is broadcast and subsequently detected.

This is determined by the frame rate of the broadcast channel, and the proportion of broadcast frames into which Identifying Data has been inserted. Hence, if Identifying Data is incorporated into every frame of the broadcast channel the number of broadcast channels that may be monitored using this approach is restricted by the frame rate of the broadcast channel.

[008] Moreover, audio data is a continuous stream and it is generally not possible to insert Identifying Data at regular intervals within the broadcast audio data since to do so would be likely to introduce unwanted perceptible artefacts into the audio stream. To overcome this problem Identifying Data is inserted into the audio data in such places and by such means as the effect of the Identifying Data on the perception of the audio data is effectively masked or concealed.

[009] For example, US 5,319,735 describes dynamic filtering of the Identifying Data as a means of masking the presence of this Identifying Data within the audio data. Inserting the Identifying Data into the audio data so that it is effectively masked or concealed usually requires that the Identifying Data be inserted at irregular intervals within the broadcast audio data. Hence monitoring audio broadcasts only for a predetermined interval during a predetermined period will not necessarily lead to the detection of the Identifying Data. Such uncertainty in the detection of the Identifying Data would undermine the reliability of monitoring broadcast channels in this way.

0] Many broadcasters utilise satellite broadcasting to distribute broadcasts on a national or international basis.

The information to be broadcast is forwarded to an up-link site where it is transmitted to the satellite. A transponder on the satellite receives these signals, amplifies them and transmits them back to earth. Due to advanced digital compression techniques each transponder is capable of transmitting a plurality of digital broadcasts and each satellite may contain a plurality of transponders.

Additionally, to enable more transponders to be used within a frequency band allocated to satellite broadcasting, transponders may use combinations of polarity. Thus, such satellites have the capacity to broadcast simultaneously a multitude of different digital broadcast channels.

1] Each satellite broadcasts information throughout its footprint' that is the area in which it is possible to receive broadcasts from the satellite. It is common for the footprint of a satellite to cover many thousands of square miles. For example, the SES-Astra 2D satellite which provides digital television and radio broadcasts for BSkyB has a footprint which covers the entire United Kingdom. Using a single monitoring site within the satellite footprint it is possible to monitor all the digital channels broadcast from a satellite.

2] Specific receiving equipment is required in order to render the information broadcast from a satellite. This includes an antenna that receives all of the signals for all of the broadcast channels for all transponders transmitting from the satellite and focuses them onto a low noise block, hereinafter referred to as the LNB. The LNB collects signals of a chosen polarity and frequency band, amplifies these signals, converts them to a different intermediate frequency (IF) and sends them to a receiver. IF splitting devices can be used to feed a particular band/polarity combination to more than one receiver. Depending upon the nature of the receiver the receiver then either performs decoding of the signals for a single broadcast channel from a given transponder, or decoding of a plurality of broadcast channels from a given transponder. The decoding involves conversion of said signals into a format compatible with a rendering device, for example a television, hi-fi system or soundcard.

These signals are then sent to the rendering device.

3] Many digital broadcasting systems use the DVB (Digital Video Broadcasting) standard to multiplex and transmit broadcast signals. Digital satellite systems use the DVB-S standard whilst DVB-T is used for broadcast signals that are delivered by a network of terrestrial transmitters and DVB-C is used for broadcast signals that are delivered by a cable distribution network. Other digital broadcasting formats can be used, such as for example ATSC, ISDB, DAB and DRM.

4] The present invention relates to means for the monitoring of broadcast channels, and in particular to managing audio using, inter alia, multi-channel digital receivers for the detection of airing. The invention has the additional advantage that it can also incorporate the monitoring of analogue broadcast channels through the conversion of these analogue channels by digital sampling.

5] An object of this invention is to provide a system and method for the monitoring of a plurality of broadcast channels simultaneously using automated means.

6] According to a first aspect of the present invention, there is provided a system as specified in claims 1 to 28.

7] According to a second aspect of the present invention, there is provided a method as specified in claims 29 to 36.

8] According to a third aspect of the present invention, there is provided a computer program as specified in claims 37 to 41.

9] Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which: [0020] Figure 1 shows a block diagram of an arrangement for receiving satellite broadcast channels, [0021] Figure 2 shows a block diagram of an arrangement for decoding of broadcast digital data channels according to the present invention, [0022] Figure 3 shows a block diagram of an arrangement for extracting and rendering received data packets that have been encapsulated within UDP and IP packets, [0023] Figure 4a shows how data from a decoded digital broadcast channel is received and encapsulated in UDP formatted packets which are then encapsulated within IP packets,

] Figure 4b shows how streams of data packets from multiple channels are uniquely labelled using the IP destination address and UDP destination port numbering scheme, [0025] Figure 5 shows a block diagram of an arrangement for receiving Digital Audio Broadcasts (DAB) according to a second embodiment of the present invention, [0026] Figure 6 shows a block diagram of the composition of the demultiplexing computer according to the second embodiment of the present invention, [0027] Figure 7 shows a block diagram of an arrangement for receiving analogue radio broadcasts according to a third embodiment of the present invention, [0028] Figure 8 shows how an analogue channel is converted to a digital data stream by digital sampling for monitoring by a system according to the present invention.

9] Figure 9 shows a block diagram of an arrangement for receiving AM or FM broadcasts (DAB) according to an aspect of the present invention, [0030] Figure 10 shows a block diagram of an arrangement for receiving and monitoring analogue channels, [0031] Figure 11 shows a block diagram of an arrangement for receiving and monitoring audio and/or video channels that are transmitted over the Internet according to the present invention, and [0032] Figure 12 shows a block diagram of an embodiment of a system according to the present invention for the monitoring of broadcast channels of different types, showing how there can be commonality of components between the front ends and processing chains.

3] The system of the present invention includes a monitoring station consisting of a means for receiving and decoding a plurality of broadcast channels, analysis of the broadcast data in each of said broadcast channels, the detection of Identifying Data embedded within said broadcast data and the creation of a log containing details of said broadcast channels in which said Identifying Data were detected and the time and date of when said Identifying Data were detected and details of the content containing said Identifying Data. Preferably the monitoring station includes a means for the simultaneous analysis of a plurality of the channels.

[0034) As shown in Figure 1, signals (14) from a transponder (12) located on a satellite (10) that is broadcasting digital channels (for example the SES ASTRA 2D satellite owned by SES ASTRA S.A., L-6815 Château de Betzdorf, Luxembourg and located at 28.2 east) are received by a combination of an appropriate antenna (16) and LNB (18) . In order to be able to receive broadcast signals from all transponders on the satellite the LNB must be capable of simultaneously receiving and re- transmitting signals broadcast by transponders using all the combinations of polarity and frequency band utilized by the broadcast satellite (10) . An example of a suitable LNB is an Invacom Quad LNB model number QDH-031, manufactured by Invacom Limited, Unit 4, Business & Technology Centre, Bessemer Drive, Stevenage, Hertfordshire, SG1 2DX, United Kingdom.

5] Referring to Figure 2, these signals are amplified by the LNB (18) and re-transmitted to an appropriate digital receiver (22) . An example of an appropriate digital receiver (22) is the S75 satellite receiver manufactured by Novra Technologies Inc. 1100-330 St. Mary Avenue Winnipeg, Manitoba, Canada R3C 3Z5. Note that a different transmission path (20) is required for the simultaneous re- transmission by the LNB (18) of each combination of polarity and frequency band that may be used by the satellite (10).

6] One or more IF splitters (19) may be required to supply appropriate signals to multiple receivers (22) for each frequency band/polarity combination. An example of an appropriate IF splitter is the SPLIT8AF manufactured by Global Communications (UK) Ltd, Winterdale Manor, Southminster Road, Aithorne, Essex CM3 6BX. The digital receiver (22) filters the received frequency band/polarity at the IF and accepts the entire broadcast data stream from a given transponder (12) and performs electronic signal processing to recover all or a selection of the original broadcast signals for the broadcast channels contained within the transponder data stream.

7] The data recovered by the digital receiver (22) from each individual broadcast channel data stream are encapsulated within UDP formatted packets within IP formatted packets, as illustrated in Figure 4a. The packets from each individual broadcast channel data stream are uniquely labeled by the receiver through the use of a unique combination of IP address and UDP port number for the UDP/IP encapsulated broadcast data packets, as illustrated in Figure 4b.

8] The said streams of UDP/IP encapsulated broadcast data packets are forwarded via an Ethernet link and Ethernet network switch (24), for example a lOOBase-TX ethernet conforming to IEEE 802.3, to a monitoring computer (26) containing a network interface card (30) and running a decoder controller application (34) using information contained within a configuration file (35) and also running a plurality of instances of a monitoring module (32) [0039] The operation of the decoder controller (34) and of the monitoring module (32) will now be described. Figure 3 shows a block diagram of an arrangement for extracting and rendering broadcast data packets that have been encapsulated within UDP and IP packets in the aforementioned manner and subsequently analysing said data and detecting and retrieving Identifying Data and subsequently producing a log file containing details of detected Identifying Data together with details of the broadcasting station that broadcast content containing the Identifying Data, the time and date at which the Identifying Data was detected and information concerning the content that contained the Identifying Data. In Figure 3, the data from the digital receiver (22) are forwarded via the Ethernet link and Ethernet network switch (24) and received by an appropriate network interface card (30) installed within an appropriate monitoring computer (26) [0040] The use of the Ethernet and Ethernet network switch (24) allows reception of data streams from multiple receivers (22) by the monitoring computer (26) . An example of an appropriate network interface card (30) is the FSD5000 manufactured by Belkin Components, 501 West Walnut Street, Compton, CA 90220. An example of the appropriate Ethernet network switch is the Netgear Fast Ethernet Switch FS116 from Netgear mc, 4500 Great America Parkway, Santa Clara California, USA. An example of an appropriate monitoring computer (26) is an IBM A50 ThinkCentre personal computer incorporating a Pentium 4 2.8Ghz processor and 256MB of RAM and using the Windows XP Professional operating system. The monitoring computer (26) runs a decoder controller application (34) developed by AlSatcom Ltd., 50 Minsterley Avenue, Shepperton, TW17 8QT and authored using the C' programming language.

1] The decoder controller application (34) instructs the - 10 monitoring computer (26) to launch, for each broadcast chanel that is to be monitored, an instance of the monitoring module (32) comprising a personal computer based audio rendering application (36) which incorporates an instance of a computer program hereinafter referred to as the input plugin (38), developed by AlSatcom Ltd., 50 Minsterley Avenue, Shepperton, TW17 8QT and authored using the C' programming language, and an instance of a further computer program hereinafter referred to as the output plugin (40) developed by Ische Limited, 108 Newland, Witney, Oxfordshire, 0X28 3JQ. An example of such an audio rendering application is Winamp' developed by America Online, Inc. 22000 AOL Way, Dunes, VA 20166.

2] The broadcast channels to be monitored are determined according to information contained within a configuration file (35) . It is usual for the broadcast channels to be monitored to correspond to those broadcast channels normally contained in the broadcast stream from one or more of the selected transponders (12) . The use of UDP and IF multicast addressing for the data streams from the receiver (22) allows multiple instances of an the monitoring module (32) running on one or more monitoring computers (26) to be logically connected to a single data stream from a receiver (22) . The network interface card (30) receives the broadcast information containing multiple individual broadcast data streams from the Ethernet link and switch (24) and makes each broadcast data stream available to the monitoring modules through IP/UDP sockets. Each data stream produced when the broadcast information is so rendered, and which still contains the broadcast signal for the selected broadcast channel is monitored by one or more instances of the monitoring module through its input plugin (38) [0043] Each instance of the input plugin (38) selects a data stream corresponding to a broadcast channel selected 11 - according to instructions received from the decoder controller application program (34) at the time when the instance of the input plugin (38) was launched. Said input plugin (38) forwards the selected data stream corresponding to a given broadcast channel to the corresponding instance of the audio rendering application (36) [0044] The output from the audio rendering application is monitored by the corresponding instance of the output plugin (40) . Each input plugin (38) and output plugin (40) is allocated a unique identification code by the decoder controller application program (34) as each instance of the plugin is launched. When Identifying Data in the output from the audio rendering application (36) is detected by the output plugin (40) a data set is created by the output plugin that contains the Identifying Data, the identification code of the output plugin (40) that identified the information containing the Identifying Data, and the time and the date that the Identifying Data was detected. Said data set is forwarded to the decoder controller application program (34), which determines the IP address and UD? port of the data stream that the input plugin (38) / rendering application (36) / output plugin (40) combination was receiving and attaches to the data set that was received from the output plugin (40) the said IP address and UDP port together with the unique identification code of the monitoring computer (26) to create a unique label that identifies the source channel of the data set within the system.

5] This modified data set is then forwarded via an Ethernet to a logging computer (42) . An example of an appropriate logging computer (42) is an IBM A50 ThinkCentre personal computer incorporating a Pentium 4 2. 8Ghz processor and 256MB of RAM and using the Windows Server 2003 operating system. The logging computer (42) uses the Identifying Data - 12 - to identify the content characterised by the Identifying Data together with other associated parameters such as title, performers and rights holders. The logging computer (42) also identifies the broadcast station by comparing the IP address, UDP port and monitoring computer identification code with a system configuration database that lists which instances of a program were logically connected to which broadcast station at any particular time. The logging computer (42) can estimate the duration of the individual airing by analyzing the duration for which Identifying Data was present on a particular broadcast channel.

6] The data set associated with the airing including content characteristics, time/date/duration of playout and the broadcast station identification is then stored in a log file. The log file may subsequently be used to provide information to interested parties concerning the number of instances in which a particular piece of content was broadcast, the broadcasting station that broadcast said content, and the time and the date on which the content was broadcast. Optionally the logging computer (42) may also provide an audible signal to alert an operator that Identifying Data has been detected and also may display on a visual display unit (44) information concerning the Identifying Data, for example the title of the content containing the Identifying Data, the time and date that the Identifying Data were detected and the identity of the broadcasting channel that broadcast the Identifying Data.

Optionally the logging computer (42) may also send a paging message, SMS message or multimedia message to users via a wireless cellular network upon the first detection of Identification Data within an airing, allowing detection information to be passed to the monitoring system users before the end of the airing.

7] From time to time, both the input plugin (38) and the - 13 - output plugin (40) send messages confirming that they are functioning correctly to the decoder controller. In the absence of such signals the decoder controller (34) automatically restarts the combination of instances of the input plugin (38), audio rendering application (36) and output plugin (40) that has failed to send such messages.

8] The above described system and process may be used to perform simultaneous monitoring of a plurality of satellite broadcasts digital channels for the detection of airing.

9] The system herein described has a number of benefits and advantages. One benefit is that broadcast channels from additional transponders on the same satellite may be monitored by using additional digital receivers (22) set up to accept the broadcast data from these transponders (12) and forward such data in UDP/IP packets via the Ethernet link and switch (24) to the monitoring computer (26) . The system has a further benefit that any broadcast channel can be received by more than one instance of an input plugin (38) and its associated rendering application (36) and output plugin (40) [0050] The system has the further benefit that any digital broadcast channel can be switched to any monitoring computer (26) and any instance of an input plugin (38) and its associated rendering application (36) and output plugin (40), allowing total operational flexibility and greater redundancy.

1] A further advantage of the present system is that it is possible using the system to monitor automatically and from a single location the entire bouquet of digital channels broadcast by a digital satellite. Broadcast signals from additional satellites can be monitored from the same site by using additional antennae, LNB5 and digital receivers.

Broadcast signals from satellites covering other regions of - 14 - the world can be monitored by locating a similar monitoring station within the appropriate footprints of the satellites.

2] The system has the additional advantage that the equipment required to perform the monitoring is very compact and modular since many digital channels may be monitored by a single monitoring computer and a plurality of monitoring computers may be used if the number of broadcast channels to be monitored exceeds the monitoring capacity of a single monitoring computer. Automatic monitoring of the correct functionality of the system may also be performed.

3] The system has the further benefit that with the addition of appropriate receivers the system can monitor airing of content on other forms of DVB-based broadcast channels, such as DVB-T and DVB-C, or on other digital broadcast systems such as ATSC and ISDB.

4] Another embodiment of the present invention will now be described. Figure 5 shows a block diagram of a front end arrangement for receiving Digital Audio Broadcasts (DAB) in which a DAB radio signal is received by an appropriate antenna (52) . The signal received by the antenna (52) is sent to an appropriate DAB receiver (54) capable of isolating an entire programme ensemble from a DAB multiplex. An example of an appropriate DAB receiver is the DREox1 manufactured by TerraTec Electronic GmbH, Herrenpfad 38, D-41334 Nettetal.

5] The digital receiver is tuned to accept the entire broadcast data stream for a chosen DAB multiplex and performs electronic signal processing to recover the broadcast signals for the DAB ensemble contained within the broadcast data stream. The signals recovered by the DAB receiver (54) are made compatible with the Receiver Data Interface (RDI) standard (BS EN 62105:2002) and forwarded by the DAB receiver via an appropriate connection (56), for example a fibre optic connection conforming to 1EC60958 (also known as S/PDIF), to - 15 - a demultiplexing computer (58) [0056] The RDI data stream includes the content of the complete DAB ensemble, including the Main Service Channel (MSC) containing all of the audio channels and the Fast Information Channel (FIC) containing information about the multiplex format. The audio data for each broadcast channel carried by the DAB multiplex within the RDI data stream is in MPEG Layer II format.

7] Figure 6 shows a block diagram of the composition of the demultiplexing computer (58) . The signals contained within the connection (56) are input to an appropriate soundcard (60) . An example of an appropriate soundcard is the Aureon 5.1 Sky PCI card manufactured by TerraTec Electronic GmbH, Herrenpfad 38, D-41334 Nettetal. The data processed by the soundcard (60) is then forwarded via an appropriate data buffer (62) to a computer program (64) hereinafter referred to as DABin', written for example using the C' programming language.

8] A alternative front end arrangement which allows the complete DAB ensemble to be passed to the "DABin" program is shown in Figure 8. Figure 8 shows a block diagram of an arrangement for receiving Digital Audio Broadcasts (DAB) in which a DAB radio signal is received by an appropriate antenna (52) . The signal received by the antenna (52) is sent to an appropriate DAB receiver module (72) capable of isolating an entire programme ensemble from a DAB multiplex.

An example of an appropriate DAB receiver module is the Roadster FS2040 manufactured by Frontier Silicon, The Belfry, Colonial Way, Watford, Hertfordshire WD24 4WH, UK.

9] The digital receiver is tuned to accept the entire broadcast data stream for a chosen DAB multiplex and performs electronic signal processing to recover the broadcast signals for the DAB ensemble contained within the broadcast data - 16 - stream. The signals recovered by the DAB receiver module (72) are made compatible with the Receiver Data Interface (RDI) standard and forwarded via an appropriate network interface module (74) and network connection (76), for example a connection and network switch conforming to Ethernet, to a demultiplexing computer (58) [0060] The RDI data stream includes the content of the complete DAB ensemble, including the Main Service Channel (MSC) containing all of the audio channels and the Fast Information Channel (FIC) containing information about the multiplex format. The audio data for each broadcast channelcarried by the DAB multiplex within the RDI data stream is in MPEG Layer II format.

1] The signals contained within the connection (76) are input to an appropriate network interface card (78) . An example of an appropriate network interface card is the FSD5000 manufactured by Belkin Components, 501 West Walnut Street, Compton, CA 90220. The data processed by the network interface card (78) is then forwarded via an appropriate data buffer (62) to a computer program (64) referred to as DABin' as mentioned previously. The data is then processed by the DABin' computer program in the same manner as shown in Figure 6 and described below.

2] The output from either of the above described DAB front ends is then passed to the rest of the system.

Referring back to Figure 6 the DABin programme (64) reads the received data stream from the soundcard (60) or network interface card (78) and assigns a unique combination of IP destination address and UDP destination port to the MPEG Layer II audio data specific to each individual broadcast channel within the data stream and converts the data from each broadcast channel into a format compatible with UDP/IP.

Preferably a multicast IP address is used to enable further processing of this data at a plurality of locations so that - 17 - the same broadcast data for a given broadcast channel may be used for different purposes, for example monitoring and recording. Thus DABin (64), receives all of the digital broadcast channels contained within the DAB ensemble and separates the data for each of the broadcast channels within the DAB ensemble into individual UDP/IP compatible packetised data streams that are each identified within the network with a unique IP address and UDP port combination, as illustrated in Figure 7. The format of each individual audio broadcast channel data stream from the DABin programme is therefore MPEG Layer II audio data contained within UDP formatted packets that are contained within IP formatted packets. Thus by converting and separating the incoming data stream from RDI to individual UDP/IP compatible data streams the DABin programme (64) is subsequently able to forward data from a specific broadcast channel to a unique IP address and UDP port combination that can be monitored by one or more monitoring modules (32) as hereinbefore described. This demultiplexing and distribution system can also be used to manage processing of the FIC (Fast Information Channel)and other data channels within the received broadcast stream.

[00631 The DABin program (64) can simultaneously process each and every broadcast channel within the DAB ensemble in such a manner described above and in this way using a single DAB receiver (54) or DAB receiver module (72) all of the broadcast audio channels from the selected DAB multiplex may be made available for monitoring simultaneously. A configuration file (65) is used that contains information used by DABin (64) to determine which combination of IP address and UDP port to assign to data corresponding to each of the broadcast channels within the DAB multiplex processed by the DAB receiver (54) [0064] Referring to Figure 3 and 6, the data from the DABin programme (64) can be monitored within the de-multiplexing - 18 - computer (58) as illustrated in Figure 6, or can be forwarded via the Ethernet link (24) to be received by an appropriate network interface card (30) installed in an appropriate monitoring computer (26) as illustrated in Figure 3. The monitoring computer (26) runs a decoder controller application (34) that instructs the monitoring computer (26) to launch for each broadcast channel that is to be monitored an instance of the monitoring module (32) comprising a personal computer based audio rendering application (36) which incorporates an instance the input plugin (38) and an instance of the output plugin (40) [0065] The broadcast channels to be monitored are determined according to information contained within a configuration file (35) . It is usual for the broadcast channels to be monitored to correspond to those broadcast channels normally contained in the broadcast stream from the selected DAB multiplex. The use of UDP and IP multicast addressing for the data streams from the de-multiplexing computer (58) allows multiple instances of the monitoring module (32) running on one or more monitoring computers (26) to be logically connected to a single data stream from a de- multiplexing computer (58) [0066] The network interface card (30) receives the broadcast information containing one or more individual broadcast data streams from the Ethernet link and Ethernet network switch (24) and makes each broadcast stream available to the monitoring modules (32) through UDP/IP sockets. Note that the functions of the de-multiplexing computer (58) and the monitoring computer (26) can be integrated into a single PC such as an IBM A50 ThinkCentre personal computer incorporating a Pentium 4 2.8Ghz processor and 256MB of RAM and using the Windows XP Professional operating system and incorporating an appropriate network interface card (30) is the FSD5000 manufactured by Belkin Components, 501 West - 19 Walnut Street, Compton, CA 90220.

7] Each data stream produced when the broadcast information is so rendered, and which still contains the broadcast signal for the selected broadcast channel is monitored by one or more instances of the monitoring module through its input plugin (38) . Each instance of the input plugin (38) selects a data stream corresponding to a broadcast channel selected according to instructions received from the decoder controller application program (34) at the' time when the instance of the input plugin (38) was launched. Said input plugin (38) forwards the selected data stream corresponding to a given broadcast channel to the corresponding instance of the audio rendering application (36) . The output from the audio rendering application is monitored by the corresponding instance of the output plugin (40) . Each input plugin (38) and output plugin (40) is allocated a unique identification code by the decoder controller application program (34) as each instance of the plugin is launched.

8] When Identifying Data in the output from the audio rendering application (36) is detected by the output plugin (40) a data set is created by the output plugin that contains the Identifying Data, the identification code of the output plugin (40) that identified the information containing the Identifying Data, and the time and the date that the Identifying Data were detected. Said data set is forwarded to the decoder controller application program (34), which determines the IP address and UDP port of the data stream that the input plugin (38) / rendering application (36) / output plugin (40) combination was receiving and attaches to the data set that was received from the output plugin (40) the said IP address and UDP port together with the unique identification code of the monitoring computer (26) to create a unique label that identifies the source channel of the - 20 - data set within the system.

9] This modified data set is then forwarded via an Ethernet or wide area network such as the Internet to a logging computer (42) . The logging computer (42) uses the Identifying Data to identify the title of the content characterised by the Identifying Data together with other associated parameters such as the content title, performers and rights holders. The logging computer (42) also identifies the broadcast station by comparing the IP address, UDP port and monitoring computer identification code with a system configuration database that lists which instances of a program were logically connected to which broadcast station at any particular time. The logging computer (42) can estimate the duration of the individual airing by analyzing the duration for which Identification Data were detected on a particular broadcast channel. The data set associated with the airing including content characteristics, time/date! duration of playout and the station identification is then stored in a log file.

0] The log file may subsequently be used to provide information to interested parties concerning the number of occasions on which a particular piece of content was broadcast, the broadcasting channel that broadcast the content, and the time and the date on which the content was broadcast. Optionally the logging computer (42) may also provide an audible signal to alert an operator that Identifying Data has been detected and also may display on a visual display unit (44) information concerning the Identifying Data, for example the title of the content containing the Identifying Data, the time and date that the Identifying Data were detected and the identity of the broadcasting channel that broadcast the Identifying Data.

1] Optionally the logging computer (42) may also send a paging message, SMS message or multimedia message to users - 21 - via a wireless cellular network upon the first detection of Identification Data within an airing, allowing detection information to be passed to the monitoring system users, before the end of the airing.

2] From time to time both the input plugin (38) and the output plugin (40) send messages confirming that they are functioning correctly to the decoder controller (34) . In the absence of such signals the decoder controller (34) automatically restarts the combination of instances of the input plugin (38), audio rendering application (36) and output plugin (40) that has failed to send such messages.

3] The above described system and process may be used to perform simultaneous monitoring of a plurality of DAB broadcast channels for the detection of airing, and has the same benefits as those described for the satellite broadcast monitoring embodiment described previously.

4] The system also has the benefit that broadcast channels from additional DAB multiplexes may be monitored by using additional DAB receivers (54) set up to accept the broadcast data from the required DAB multiplexes and forward such data across an additional connection (56) to an additional soundcard (60) within the de-multiplexing computer (58). An additional data buffer (62) and DABin computer program (64) can then be used to create individual data streams for each broadcast channel with a unique IP address and [JDP port combination that can be monitored in the aforementioned manner by the de-multiplexing computer (58) or monitoring computer (26) . Additional de-multiplexing computers (58) can be added should the capacity of a single de-multiplexing computer to receive and process the RDI data streams from multiple DAB receivers (54) be exceeded.

5] The system has the further advantage that monitoring stations can be located in remote monitoring sites to monitor - 22 - localized DAB broadcasts and reporting individual Identification Data detections and/or airings back to a centralized logging computer (42) over a wide area network such as the Internet. The remote monitoring station consists of one or more DAB antennas (52), DAB receivers (54), connections (56), soundcards (60), data buffers (62), DAB1n computer programs (64) and one or more de-multiplexing computers (58) and monitoring computers (26) running multiple instances of the input plugin (38), rendering application (36) and output plugin (40) [0076] The system has the further benefit that the functions of the de- multiplexing computer (58) and the monitoring computer (26) can be integrated into a single PC.

7] The system has the additional benefit that with the addition of appropriate receivers the system can monitor airing of content on other forms of digital radio broadcast channels, such as DRM, DSR and ISDB.

8] A further embodiment of the present invention will now be described which involves the monitoring of radio stations transmitted using wavelengths associated with the technique of Frequency Modulation, hereinafter referred to as FM, and the technique of Amplitude Modulation, herein after referred to as AM.

9] Referring to Figure 9 broadcasts from a transmitter (80) transmitting signals associated with AM and/or FM are received by an antenna (82) . The signals from the antenna (82) are sent to an AM/FM receiver (84) which selects and decodes the signals for a specified radio station. An example of an appropriate AM/FM receiver is the DRA-455 manufactured by Denon UK Ltd., Chiltern Hill, Chalfont St. Peter, Gerrards Cross, Buckinghamshire, SL9 9UG. Means for selecting a radio station for decoding using an AM/FM receiver are well known to one skilled in the art.

- 23 - [0080] Referring to Figure 10 analogue signals from the receiver (84) are sent to a soundcard (90) to be digitally sampled, for example a Soundblaster Live PCI card manufactured by Creative Technology Ltd., 31 International Business Park, Creative Resource, Singapore 609921, Republic of Singapore. The soundcard (90) digitally samples the incoming analogue signal from the receiver (84) to create a digital stream containing the broadcast signal. The soundcard (90) may be incorporated within a monitoring computer (26) or de- multiplexing computer (58) described hereinbefore.

1] An instance of an AM/FM decoder controller application (96), developed by Al Satcom Ltd., 50 Minsterley Avenue, Shepperton, TW17 8QT and written using the C programming language, instructs the monitoring computer (26) to launch an instance of an audio rendering application (36) for each AM or FM broadcast channel to be monitored. The soundcard channel or channels and hence the associated AM / FM channel to be monitored is determined according to instructions contained within a configuration file (94) . Each instance of the audio rendering application so launched also incorporates an instance of a computer programme hereinafter referred to as the AM/FM Input Plugin (92) and an instance of the output plugin (40) hereinbefore described. An example of an appropriate AM/FM Input plugin (92) is Lineln Plugin V1.80, available at http://www.winamp.com. The configuration file (94) used by the AM/FM decoder controller application (96) contains command lines that instruct each AM/FM Input plugin (92) to receive channels from a specified soundcard (90) which is receiving signals from a specified AM/FM receiver (84) tuned to receive signals from a known AM/FM broadcasting channel.

2] The soundcard (90) processes the signals from the receiver (84) and renders them into a digital format compatible with the AM/FM Input plugin (92). The AM/FM Input - 24 - plugin (92) inputs the signals from the soundcard (90) to the audio rendering application (36) . The output from the audio rendering application (36) is monitored by the corresponding instance of the output plugin (40) . Each output plugin (40) is allocated a unique identification code by the AI"l/FM decoder controller application program (96) as each instance of the plugin is launched. When Identifying Data in the output from the audio rendering application (36) is detected by the output plugin (40) a data set is created by the output plugin that contains the Identifying Data, the identification code of the output plugin (40) that identified the information containing the Identifying Data and the time and the date that the Identifying Data was detected.

3] The data set is forwarded to the AM/FM decoder controller application (96) which attaches to the data set a unique label to describe the soundcard channel on which the output plugin (40) was listening and the unique identification code of the monitoring computer (26) . This modified data set is then forwarded via an Ethernet or a wide area network such as the Internet to a logging computer (42)..

[00841 The logging computer (42) uses the Identifying Data to identify the content characterized by the Identifying Data together with other associated parameters such as the content title, performers and rights holders. The logging computer (42) also identifies the broadcast station by comparing the unique soundcard channel label and monitoring computer identification code with a system configuration database that lists which instances of a program were logically connected to which broadcast station at any particular time. The logging computer (42) can estimate the duration of the individual airing by analyzing the duration for which Identification Data were detected on a particular broadcast channel. The data set associated with the airing including - 25 - content characteristics, time/date/duration of playout and the station identification is then stored in a log file.

5] The log file may subsequently be used to provide information to interested parties, such as for example information concerning the number of occasions on which a particular piece of content was broadcast, the broadcasting channel that broadcast the content, and the time and the date on which the content was broadcast. Optionally the logging computer (42) may also provide an audible signal to alert an operator that Identifying Data has been detected and also may display on a visual display unit (44) information concerning the Identifying Data, for example the title of the content containing the Identifying Data, the time and date that the Identifying Data were detected and the identity of the broadcasting channel that broadcast the Identifying Data.

6] Optionally the logging computer (42) may also send a message such as a paging message, SMS message or multimedia message to users via a wireless cellular network upon the first detection of Identification Data within an airing, allowing detection information to be passed to the monitoring system users before the end of the airing.

7] The AM/FM decoder controller application (96) also monitors all instances of the combination of the AM/FM input plugin (92), audio rendering application (36) and output plugin (40) and automatically restarts any that have halted.

8] A further embodiment of the present invention involves the monitoring of audio and/or video transmitted over the Internet using digital media streaming technologies such as Real Media from Real Networks Inc or Windows Media from Microsoft Corporation.

9] This embodiment is shown in Figure 11, where the monitoring computer (26) connects to the broadcast server (100) via the Internet (102) . The broadcast server then - 26 - transmits the broadcast signal via the Internet (102) to the monitoring computer (26) having a network interface card (30) in a digital media streaming format such as Real Media or Windows Media.

0] Referring to Figure 11 an instance of an Internet decoder controller application (104), developed by Al Satcom Ltd., 50 Minsterley Avenue, Shepperton, TW17 8QT and written using the C programming language, instructs the monitoring computer (26) to launch an instance of an audio rendering application (36) for each Internet broadcast channel to be monitored.

1] The Uniform Resource Locator (URL) string of the Internet broadcast channel to be monitored is determined according to instructions contained within a configuration file (106) . Each instance of the audio rendering application so launched also incorporates an instance of a computer programme hereinafter referred to as the Internet Input Plugin (108) and an instance of the output plugin (40) hereinbefore described. An example of an appropriate Internet Input plugin (108) for Real media format is Tara's Real Audio Input Plugin vl.0.3b for Winamp [intara.dll] available from http://www.music1iveson1ine.com/software/watara.htm1 or for Microsoft Windows Media format is Nuilsoft WMA pig-in cv.04(x86) [inwm.dli] available from http://www.winamp.com.

2] The configuration file (106) used by the Internet decoder controller application (104) contains command line parameters that instruct each Internet Input plugin (92) to receive a channel from a specified URL for a known Internet broadcasting channel on the World Wide Web. An example format of the URL command parameters for the Real media input plugin is rtsp: //lonrle.interoutemediaservices.com/split/ 10.1.17.10/live/radio/forth2.rm and for the Windows Media input plugin is mms://live.interoutemediaservices.com/ fortham/ . wma.

- 27 - [0093] The Internet Input plugin (108) logically connects onto the desired digital media stream and inputs the signals from the Internet broadcast source to the audio or video rendering application (36) . The output from the audio rendering application (36) is monitored by the corresponding instance of the output plugin (40) . Each output plugin (40) is allocated a unique identification code by the Internet decoder controller application program (104) as each instance of the plugin is launched. When Identifying Data in the output from the audio rendering application (36) is detected by the output plugin (40) a data set is created by the output plugin that contains the Identifying Data, the identification code of the output plugin (40) that identified the information containing the Identifying Data and the time and the date that the Identifying Data was detected.

4] The data set is forwarded to the Internet decoder controller application (104) which attaches to the data set a unique label to describe the Internet streaming source on which the output plugin (40) was listening and the unique identification code of the monitoring computer (26) . This modified data set is then forwarded via an Ethernet or a wide area network such as the Internet to a logging computer (42) [0095] The logging computer (42) uses the Identifying Data to identify the content characterised by the Identifying Data together with other associated parameters such as the content title, performers and rights holders. The logging computer (42) also identifies the broadcast station by comparing the unique source channel label and monitoring computer identification code with a system configuration database that lists which instances of a program were logically connected to which broadcast station at any particular time.

6] The logging computer (42) can estimate the duration of the individual airing by analysing the duration for which - 28 Identification Data were detected on a particular broadcast channel. The data set associated with the airing including content characteristics, time/date/duration of playout and the station identification is then stored in a log file. The log file may subsequently be used to provide information to interested parties concerning the number of occasions on which a particular piece of content was broadcast, the broadcasting channel that broadcast the content, and the time and the date on which the content was broadcast.

7] Optionally the logging computer (42) may also provide an audible signal to alert an operator that Identifying Data has been detected and also may display on a visual display unit (44) information concerning the Identifying Data, for example the title of the content containing the Identifying Data, the time and date that the Identifying Data were detected and the identity of the broadcasting channel that broadcast the Identifying Data. Optionally the logging computer (42) may also send a paging message, SMS message or multimedia message to users via a wireless cellular network upon the first detection of Identification Data within an airing, allowing detection information to be passed to the monitoring system users before the end of the airing.

8] The Internet decoder controller application (104) also monitors all instances of the combination of the Internet input plugin (108), audio or video rendering application (36) and output plugin (40) and automatically restarts any that have halted.

9] Figure 12 illustrates how the present invention can allow simultaneous monitoring of broadcast channels of different types for Identifying Data. Figure 12 shows how both monitoring computers (26) and de-multiplexing computers (58) can be coupled or connected to a common logging computer (42) . The reception and processing of each type of broadcast channel has been described in previous sections of - 29 - the description. The modular architecture of the system, together with the use of a common labelling format allows integration of different front ends to allow simultaneous monitoring of different types of broadcast channel.

[00100] For example, analogue broadcast channels such as AM and FM radio may be monitored using an appropriate antenna (82) and receiver (84) that distributes or passes the received broadcast channel in analogue audio format to the soundcard (92) in the monitoring computer (26) . This soundcard samples the analogue audio signal and passes the digitized broadcast data stream to the audio rendering application (36) via the AM/FM input plugin (92) . Detections of Identifying Data from the output plugin (40) are labelled by the AM/FM decoder controller (96) to uniquely identify the source broadcast channel within the system, and these labelled instances of detection are then passed on to the logging computer (42) .In this case the monitoring module comprises plugin 92, output plugin 40 and audio rendering application 36.

[00101] Multiplexed DAB broadcast channels are monitored using an appropriate antenna (52) and DAB receiver configuration (54 or 73) . In the case of the DAB receiver 54, the complete DAB ensemble is passed to the demultiplexing computer in RDI format over a connection such as a fibre optic connection conforming to lEO 60958 (also known as S/PDIF), and is received in the demultiplexing computer via a soundcard with an appropriate input such as optical S/PDIF.

In the case of DAB receiver 73, incorporating a DAB receiver module (72) and network interface module (74), the complete DAB ensemble is passed to the de-multiplexing computer over a connection such as a connection 76 conforming to Ethernet protocols, and is received in the de-multiplexing computer 58 via a network interface card 78.

[00102] In both cases, the multiplexed DAB broadcast stream - 30 - is then de-multiplexed by the DABin programme 64, and each individual data stream within the multiplexed DAB broadcast is distributed, for example in a format compatible with UDP/IP, for reception by one or more monitoring modules (32) through its input plugin 38. As discussed previously, the monitoring modules can be hosted in the demultiplexing computer, or the individual de-multiplexed broadcast channels can be passed to monitoring computers (26) via a network connection. Detections of Identifying Data from the output plugin (40) within the monitoring modules (32) are labelled by the decoder controller application program (34) to uniquely identify the source broadcast channel within the system, and these labelled instances of detection are then passed on to the logging computer (42) [00103] Multiplexed DVB broadcast channels can be monitored using an appropriate satellite front end (11) consisting of an antenna (16), LNB (18), transmission path (20) and splitters (19) together with one or more digital receivers (22). The digital receiver de-multiplexes the received multiplexed DVB broadcast stream and each individual data stream within the broadcast stream is distributed in a format compatible with, for example, UDP/IP via a network connection for reception by one or more monitoring modules (32) through its input plugin 38. As discussed previously, the monitoring modules can be hosted on one or more monitoring computers (26) that are connected to one or more digital receivers (22)via a network connection (24) and network interface card (30) within each monitoring computer. Detections of Identifying Data from the output plugin (40) within the monitoring modules (32) are labelled by the decoder controller application program (34) to uniquely identify the source broadcast channel within the system, and these labelled instances of detection are then passed on to the logging computer (42) - 31 - [00104] Broadcast channels which are distributed via the Internet (102) using digital streaming formats such as Real Media or Windows Media may be monitored using a network interface card (30) within a monitoring computer (26). The URL of the desired broadcast channel is used by the Internetinput plugin (108) to logically connect the audio rendering application (36) and associated output plugin (40) to the broadcast channel. Detections of Identifying Data from the output plugin (40) are labelled by the Internet decoder controller application program (104) to uniquely identify the source broadcast channel within the system, and these labelled instances of detection are then passed on to the logging computer (42) . In this case the monitoring module comprises input plugin 108, output plugin 40 and audio or video rendering application 36.

[00105] Figure 12 highlights the commonality of components between the front ends and processing chains for the monitoring of broadcast channels of different types. In all cases a common audio rendering application (36) can be used to render the audio and a common output plugin (40) can be used to detect the presence of Identifying Data within the broadcast data stream. The use of a common distribution mechanism and a common UDP/IP addressing scheme for multiplexed digital broadcast channels such as DVB and DAB allows a common monitoring module (32) to be used for both types of multiplexed digital broadcast channels. In addition, the use of a common labelling scheme by the different types of decoder controller (96, 34, 104) to identify broadcast channels within the system allows detections of Identifying Data from different types of broadcast channel to be logged and processed using a common logging computer (42) [00106] The monitoring computer (26) may perform simultaneous monitoring of data from all or combinations of each of the above embodiments thus enabling simultaneous monitoring of - 32 - multiple DVB, DAB, Internet and/or AM/FM broadcasts from a single location using a small amount of hardware occupying a small physical footprint. Such an arrangement has the advantage that monitoring of broadcast channels may be performed economically.

[00107] The system described has a number of benefits and advantages. The system can simultaneously monitor different types of broadcast channel. The simultaneous monitoring of different types of broadcast channel can be performed within one monitoring computer and/or one demultiplexing computer.

[00108] Common interfacing of the output plugin allows other types of output plugin performing different functions, such as for example recording of channels, to be easily incorporated into the system.

[00109] In general, for both digital and analogue channels the monitoring module for a given channel comprises an input plugin, a rendering application, and an output plugin, although other features (such as a recording function) can also be included.

[00110] Elements of the present system may be distributed to remote locations to allow monitoring of localized broadcast signals across the country or wider area with communication to the centralized elements being performed over a wide area network such as the Internet.

[00111] The logging means can be located at remote receiving sites. Some recording of individual watermark detections is done at such remote sites may be performed for failure recovery purposes. However, the main logging and subsequent processing preferably occurs at a central reporting unit.

[00112] Such subsequent processing can include airing duration estimation. A playout of a piece of content on a station is typically characterized by a series of watermark - 33 - detections a few seconds apart in the time domain. The remote receiving sites send back the individual detected watermarks to the central reporting unit PC which processes these streams to create a single record in a playouts database for that particular playout. The central reporting unit hosts the playouts database and presents the playouts information to the user, for example over the web. Thus the central reporting unit can either be remote from the logging means or collocated.

[00113] The monitoring system can be modified to incorporate appropriate receivers to allow simultaneous monitoring of broadcasts data from all forms of broadcast formats including DVB-T, DVB-C, DVB-S, DVB-H, ATSC, ISDB, DRM, DAB or combinations thereof.

[00114] In summary, a system and method has been described for monitoring a plurality of multiplexed channels and other optional channels simultaneously for content including Identifying Data, such as watermark or fingerprint data. The system comprising: receiving means for receiving a plurality of broadcast or transmitted channels; a distribution module for sending the received data stream corresponding to at least some of the channels to a unique port on a computer or network in a format such as a UDP/IP packet format; a conversion module for converting the data stream at a given port into a format suitable for decoding; a decoder module for monitoring the data stream of each selected channel for said Identifying Data; and logging means for storing the output of said decoder module including said Identifying Data and related information such as the identity of the channel involved and/or broadcast or transmission times and duration of airing.

[00115] The system is very scaleable and flexible, and can provide simultaneous monitoring of tens or hundreds of channels at low cost. A system can be provided with a two or - 34 - more monitoring modules for a given channel, so as to decode Identifying Data encoded using different methods or having different formats.

[00116] The detailed embodiments described herein have been provided for purely illustrative purposes, and all equivalent means of providing the functionality of the described system and method known to the person skilled in the art are intended to be within the scope of the accompanying claims.

Claims (41)

- 35 - CLAIMS

1. A system for monitoring a plurality of channels for content including Identifying Data at the same time, the system consisting of or including: receiving means for receiving a plurality of broadcast or transmitted channels; a distribution module for sending the received data stream from one or more digital multiplexed channels in a predetermined format to a unique port on a computer or network; a monitoring module for converting the data stream at a given port into a format suitable for decoding, and decoding and monitoring the data stream for said Identifying Data; and logging means for storing the output of said monitoring module including said Identifying Data and related information such as the identity of the channel involved and/or broadcast or transmission times.

2. A system as claimed in claim 1, in which the receiving means includes a multichannel receiver module and at least one channel is broadcast using a Digital Television format.

3. A system as claimed in claim 1 or claim 2, in which the receiving means includes a multichannel receiver module and at least one channel is broadcast using ATSC or ISDB digital video formats.

4. A system as claimed in claim 1 or claim 2, in which the receiving means includes a multichannel receiver module and at least one channel is broadcast using Digital Video Broadcasting (DVB) format.

5. A system as claimed in claim 4, in which the at least one channel is broadcast using one of the group of formats - 36 - consisting of: DVB-T, DVB-C, DVB-S and DVB-H.

6. A system as claimed in claim 1, in which the receiving means includes a multichannel receiver module and at least one channel is broadcast using a Digital Radio format.

7. A system as claimed in claim 1 or claim 6, in which the receiving means includes a multichannel receiver module and at least one channel is broadcast using Digital Audio Broadcasting (DAB) format.

8. A system as claimed in claim 1 or claim 6 in which the receiving means includes a multichannel receiver module and at least one channel is broadcast using DRM format.

9. A system as claimed in claim 6 in which the Digital radio format is DVB format.

10. A system as claimed in any preceding claim in which at least one channel is an analogue channel which is converted to a digital data stream by sampling and made available to the monitoring module.

11. A system as claimed in claim 10, in which said at least one analogue channel is broadcast or transmitted using Amplitude Modulation (AM).

12. A system as claimed in claim 10, in which said at least one analogue channel is broadcast or transmitted using Frequency Modulation (FM)

13. A broadcast monitoring system as claimed in any preceding claim in which at least one channel is transmitted via the Internet or the world- wide-web and made available to the monitoring module.

14. A system as claimed in any preceding claim in which the distribution module comprises software running on a computer.

- 37 -

15. A system as claimed in any preceding claim in which the monitoring module and logging module comprise software running on a computer.

16. A system as claimed in any preceding claim having a plurality of multichannel receiver modules and/or distribution modules so as to monitor a greater number of channels.

17. A system as claimed in any preceding claim having a plurality of monitoring modules for a given channel so as to decode Identifying Data encoded using different methods or having different formats.

18. A system as claimed in any preceding claim in which the data stored by the logging means is sent to a central reporting unit.

19. A system as claimed in any one of claims 1 to 17 in which the data stored by the logging means is arranged to be read by a central reporting unit.

20. A system as claimed in claim 18 or 19 in which the central reporting unit is remotely located relative to the other modules of the system and communicates with the logging module via a network such as the internet, wide area computer network, or telephone system.

21. A system as claimed in any preceding claim in which the logging means is located in the central reporting unit remote from the receiving means.

22. A system as claimed in claims 18 to 21 in which the logging means sends a message such as a paging message, SMS message or multimedia message to users via a wireless cellular network when predetermined Identification Data is first detected in a given airing in a given channel.

23. A system as claimed in any preceding claim in which - 38 - the Identifying Data is fingerprint data.

24. A system as claimed in any one of claims 1 to 22 in which the Identifying Data is watermark data.

25. A system as claimed in any preceding claim in which the channels to be monitored are selectable.

26. A system as claimed in any preceding claim having a system management module for ensuring correct operation of the modules and for enabling automatic restart of modules.

27. A system as claimed in any preceding claim in which the Identifying Data from each channel is labelled with a unique system channel identification label to enable the logging means to identify the source broadcast channel.

28. A system as claimed in any preceding claim including a recording module for recording the data stream from one or more given ports.

29. A method of monitoring a plurality of channels for content including Identifying Data, the method consisting of or including- a. receiving a signal comprising a plurality of multiplexed broadcast or transmitted channels at a multichannel receiver; b. demultiplexing the signal into a plurality of separate channels; c. formatting the information in each channel into a sequence of data packets; d. distributing the plurality of sequences of data packets to respective unique ports on a computer or network; and e. monitoring the channels for Identifying Data.

30. A method of monitoring a plurality of channels as claimed in claim 29, in which step e comprises:- - 39 - f. converting the sequences of data packets at each port into a format suitable for decoding; g. decoding the information from the data packets to retrieve the Identifying Data for each channel; and h. storing said Identifying Data and related information such as the identity of the channel involved and/or broadcast or transmission times or durations.

31. A method as claimed in claim 29 or 30, in which the information in each channel is formatted into User Datagram Protocol (UDP) packets which are incorporated into Internet Protocol (IP) packets.

32. A method as claimed in any one of claims 29 to 31 in which the multiplexed broadcast or transmitted channels comprise signals in Digital Television and/or Digital radio formats.

33. A method as claimed in claim 32 in which the signal is a digital audio broadcasting (DAB) signal, and the individual channels contained within the receiver data interface (RDI) data or Main Service Channel (MSC) from said DAB signal are encapsulated within User Datagram Protocol (UDP) packets within IP packets and are each transmitted across a network using unique IP address and port combinations to allow subsequent filtering and/or processing.

34. A method as claimed in claim 32 in which the signal is a digital audio broadcasting (DAB) signal, and the Main Service Channel (MSC) or receiver data interface (RDI) data from the receiver is transmitted to the demultiplexing means across a network using unique IP address and port combinations to allow subsequent filtering and/or processing.

35. A method as claimed in any one of claims 29 to 34 in which one or more additional analogue channels are received, - 40 - sampled and decoded to retrieve Identifying Data.

36. A method as claimed in any one of claims 29 to 35 including recording the signal from one or more of the broadcast or transmitted channels.

37. A computer program which, when loaded into a computer, performs a method according to any one of claims 27 to 36.

38. A computer program which, when loaded into a computer, controls a system according to any one of claims 1 to 28 to receive signals containing data from a plurality of broadcast or transmitted channels to subsequently monitor said data from multiple individual channels within said signals for Identifying Data, and for processing the data so that a plurality of individual broadcast channels may be monitored at the same time.

39. A computer program according to claim 38, in which digital data from selected individual channels is uniquely labelled and distributed on a local network together with data from multiple other individual broadcast or transmitted channels, each of said individual broadcast or transmitted channels also being uniquely labelled.

40. A computer program according to claims 38 or 39 in which signals compatible with the receiver data interface (RDI) or Main Service Channel (MSC) of the digital audio broadcasting (DAB) system are interrogated to filter said data according to one or more broadcast channels and are subsequently separated and said data from individual broadcast channels is uniquely labelled to facilitate later processing.

41. A computer program according to any one of claims 38 to 40 in which data from the channels is labeled in a format compatible with UDP/IP formats.