WO2002017429A1

WO2002017429A1 - System and method for media audience measurement

Info

Publication number: WO2002017429A1
Application number: PCT/SE2001/001780
Authority: WO
Inventors: Jan Brandberg
Original assignee: D-Ratings Digital Ratings Services Ab -
Priority date: 2000-08-21
Filing date: 2001-08-21
Publication date: 2002-02-28
Also published as: AU2001282772A1; EP1312212A1

Abstract

Method and system for media audience measurement, comprising a data receiving unit (1) with a first input (2) for an incoming digital, coded data stream (3), a channel selection device (4) for extracting data, comprising media data and control data, belonging to a selected media channel from said data stream, and a decoding device (5) for decoding extracted data. The system is characterized by a detecting device (8) devised to detect channel information for the new, extracted media channel from decoded control data, upon change of selected media channel, for presentation on a presentation unit (7). The detecting devices preferably comprises the data receiving unit's computer system (30) programmed with a special software, the software of which causes detection and output of said channel information. A data gathering unit (9), is devised, at a media channel change, to store detected channel information for the new media channel in combination with timing data for said media channel channel change. The procedure to detect the channel information after the control data has been decoded in the data receiving unit's decoding device, results in the channel information being shown in plain text immediately when the channel change takes places.

Description

SYSTEM AND METHOD FOR MEDIA AUDIENCE MEASUREMENT

THE AREA OF INVENTION The present invention relates to systems and methods for monitoring and measuring audience and users of different kinds of media, particularly such media as are presentable in pictures and/or sound on TV or radio sets. In particular the present invention aims at measuring media audience, which has the possibility to receive information from different sources and of different types from a presentation unit, the information of which may be both analog and digital.

BACKGROUND

TV audience measurement by way of so called Peoplemeters is done in most markets where commercial TV is established. The method means that measuring instruments, so called Peoplemeters, are connected to existing TV sets in private households. The meter registers and stores information about what individual persons in the household are wiewing. This information is then transmitted by way of a modem to a central computer for further processing. Existing measuring equipment is adapted to analog equipment, as analog terrestrial or cable bound TV reception has been the prevalent procedure. By the introduction of digital TV, new requirements are made on measuring equipment for audience measurement.

Basically two methods to detect which digital TV channel is presented by means of a meter is presented in US 5,974,299 by Masetti. According to one variant the meter detects in parallel the complete time division multiplexed data stream, comprising media data for a number of channels and a check stream, put into a integrated receiver and decoder for digital media, i.e. set top box in the case of digital TV. Then the meter detects the data stream, comprising media data for one channel and the check stream, which streams from the set top box to the TV set, i.e. the data stream representing the selected TV channel. The meter then makes a comparison between the two detected streams until a match is reached, whereby check codes for the matched stream are detected and stored. This procedure is of course demanding when it comes to either processor power or time, and nevertheless does not lead to the channel identity being obtained without further processing. In another variant the selected data stream running from the set top box is put out in parallel from the common interface port which otherwise is used among other things for decoding coded transmissions, i.e. pay channels or pay services. One problem with the suggested variant is that the channel identity is not obtained without further processing of the check stream. Furthermore, tapping off digitally coded data means that you have reached a deadlock and only can extract information from digital broadcasts. According to Masetti data stored in the meter is sent by way of a modem to a central computer. By way of a code key for the data streams located in the central computer you can then in plain text read what is shown on the household's TV set.

In US 6,061,082 by Park a procedure for Internet TV audience measurement is described. According to the suggested solution, the TV signal sent out is prepared with a channel search command. Said channel search command is activated when the TV signal is decoded at the recipient thereby analyses current TV channel and then reports by way of an e-mail that the recipient in question is viewing the current channel.

The prior art furthermore includes JP 11355228 A and JP 11298922 A, which both are about methods for TV audience measurement by using a PC connected to a TV set. JP 11275607 A concerns an audience measurement system, where a modem, available in the household, is used to transmit data from the household.

Known technique furthermore includes JP 11355228 A and JP 11298922 A, which both are about methods for TV audience measurement by using a PC connected to a TV set. JP 11275607 A is about an audience measurement system, where a modem, available in the household, is used to transmit data from the household.

In WO 00/16552 by Hamid et.al a system and procedure for monitoring TV viewing is described, wherein a cable TV box according to prior art is set up. The solution is based on the conception that it is not desirable to set up another box for gathering and storing information about TV viewing, and therefore instead suggests that a software application for gathering and storing data is downloaded into the existing box. The solution emanates from the author's opinion that there is extra space in the data storage memory for the box's microprocessor in existing cable TV boxes, which extra space is used to buffer viewer information before it is transmitted to a central computer by way of a modem or some other way. However, in today's cable TV or set top boxes there is as a rule no such extra space, and in any case it cannot be guaranteed to exist. As the author himself has written, such an extra space, if any, can be set up for the operator to be able to make future changes and upgrades to the software. If there would be such an extra space, and it would be taken up by stored viewer data, the operator's possibilities to make such changes will of course be impaired. Furthermore, the solution is not possible to set up in set top boxes for digital TV which use operating systems of the Open TV type or similar, which apart from TV viewing make interactive applications possible. The reason for this is that such operating systems only allow one application to be run at a time, and therefore cannot handle yet another application for gathering data. The suggested solution is not at all set up or suitable to perform audience measurements regarding anything but pure TV viewing. Furthermore, to set up the measurement in the existing box is burdened by the problem that such a box does not register if the TV set to which it is connected is on or off. The set top box itself is usually constantly on, but to be able to measure for how long a viewer is viewing TV, of course you also have to know if the TV set is on.

OBJECT OF THE INVENTION

A general object of the present invention is to supply a system and a method for media audience measurement which overcome the problems with known technique. More precisely it is an object to achieve media audience measurement by using existing equipment for receiving and decoding digital data in the best possible way.

One aspect of this object is to achieve a fast and reliable measurement of what is presented to the media audience, even for very short periods.

Another aspect of this object is to be able to perform media audience measurement regarding presented media data from different sources and of different types, the media data of which can be obtained in both analog and digital ways.

SUMMARY OF THE INVENTION

To achieve the above-mentioned object, the present relates to, according to a first aspect, a system for media audience measurement, comprising a data receiving unit with a first input for an incoming digital coded data stream, a channel selection device for extracting data, comprising media data and control data, associated with a selected media channel from said data stream, and a decoding device for decoding extracted data. Said media preferably comprises TV, radio and interactive services over these carriers. Thus said data receiving unit is preferably a set top box or similar, as a separate or integrated unit. A media presentation unit, e.g. a TV, radio or PC, is devised for the presentation of extracted and decoded media data, i.e. preferably audio and/or video data. The system is characterized by a detecting device devised to, at a change of selected media channel, detect channel information for the new extracted media channel from the decoded control data. The detecting device preferably comprises the data receiving unit's computer system programmed with a special software, which software causes detection and output of said channel information. A data gathering unit, separate from or integrated with the data receiving unit and/or the media presentation unit is devised to, at a media channel change, store detected channel information for the new media channel in combination with timing data for said media channel change. The procedure to detect the channel information after the control data has been decoded in the data receiving unit's decoding device, makes the channel information available in plain text immediately when the channel change takes place. This means that no subsequent processing is needed when it comes to decode detected data, or to relate detected data to the actual time of the channel change.

Preferably a communication unit, e.g. a modem, is connectable to said data gathering unit and also devised to transmit data stored in the data gathering unit through a communication connection to an external storage medium. Said data gathering unit preferably comprises a clock device or an input for a clock pulse, devised to provide said timing data.

A measuring device comprising said data gathering unit further comprises a computer system and a data stream switch with a first input devised for input of decoded media data from said decoding device, and a second input for input of media data from an alternative media source, which data stream switch is controlled by said measuring device's computer system. Alternative sources can be local video from VHS or DVD, or analog TV.

In case the data receiving unit does not comprise a teletext decoder, the measuring device does, devised to detect the presentation of a teletext page on the screen of the TV set, and devised to transmit a message comprising identity information about the currently presented page, addressed to said data gathering unit.

In one embodiment, the presentation unit is devised with a sensing device adapted to sense when the TV sets is turned on to transmit a power up signal thereupon. This sensing device, in one embodiment, can indicate that the TV set is on, by adding a potential to one of the pins in its scart output. In an alternative embodiment, the sensing device can comprise a probe detecting high voltage over the TV tube. An image communication device is devised to present a login message on said TV screen, in dependence of said power up signal. A data input device, preferably a remote control, is devised for communication with a data receiving device, which is communicatively connected to said image communication device, which data input device comprises means, e.g. keys, for entering login data. Preferably, the users or viewers belonging to the household where the data gathering unit is set up are known through a registration made when signing an agreement about permitting the media use being measured. Therewith the members of the household have been assigned a code each, constituting the login data, which can be multi-digit or only correspond to the pressing of one key, e.g. "1", on the data input device. This code thereby identifies the viewer to the data gathering unit. According to a second aspect, the present invention relates to involves a method for measuring media audience, comprising the steps to:

- receive a digital coded data stream from an external source;

- detect and store login data from a media user; - select a first media channel for presentation;

- extract data, comprising media data and control data, associated with said first media channel from said data stream;

- decode extracted data;

- present the decoded media data; - detect, in the decoded control data, the channel information for the selected media channel;

- store detected channel information in combination with timing data for said selection.

Further, the method preferably comprises the steps to: - transmit the stored login data and the combined channel formation and timing data to an external storage medium;

- store transmitted data in the external storage medium.

The steps to detect and store channel information preferably comprise the steps to: - at a channel change from a first selected media channel to a second selected media channel, detect identity data in plain text for said second media channel from the decoded control data;

- detect the time for the selection of said second selected media channel;

- store said identity data in combination with a time stamp for said time. According to the present invention, it is also possible to select media types using the same carrier. For TV different media types are TV programs, teletext, interactive services, electronic program guide etc. The method thus further comprises the steps to:

- detect and store login data from a media user; - select media type for presentation;

- detect selected media type;

- detect the time of the selection of said media type;

- store information about said media type in combination with a time stamp for said time. Different media sources can of course be used for providing data to be presented on the presentation device. Different inputs from different TV receivers can occur, receivers for both digital and analog TV, video, etc. The method according to the invention thus further comprises the steps to:

- detect and store login data from a media user; - select media source for obtaining media data for presentation;

- detect selected media source;

- detect the time of the selection of said media source;

- store information about said media type in combination with a time stamp for said time.

When said media is TV, the said media channel is preferably a TV channel. If said media type is teletext, said media channel represents one teletext page. For interactive programs, said media channel represents different traces.

The method according to the present invention preferably further comprises the steps to:

- sense when a presentation unit for said presentation is turned on;

- present a login message on said presentation unit as a reaction to the power up of the presentation unit;

- log in identity information for current media audience with a data entering device, preferably a remote control;

- store login identity information in combination with a time stamp for said power up operation.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is described in further detail below, in the form of exemplified embodiments with simultaneous reference to the drawings, on which Figure 1 - 4 show some different general ways to implement the invention; Figure 5 shows included parts of one embodiment of a system according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention relates to a new measuring instrument intended to be connected to or integrated with a digital set top box (STB), to make measurements possible also from households receiving digitally transmitted TV and radio. How things may look inside the home is outlined in the figures 1 - 4. A data receiving unit 1 is devised for receiving a digital coded data stream 3. The unit 1 is adapted to select what the audience, one person or more, wishes to view or hear on its presentation unit 7, as well as adapted to decode the data for the selected material, a chosen channel. In the case of TV the data receiving unit 1 is an STB 1 and the presentation unit 7 is a TV with a screen 22, but of course the invention may be implemented for audio only, wherein the presentation unit is a radio 7. However henceforth the example TV will be discussed in the first place. In figure 1 the STB is devised to send TV data for the selected channel, i.e. video 27 and audio 28, to the TV set 7, and to send channel identity information 29 for the selected channel in parallel to a measurement box 13. The measurement box 13 comprises a communication device, preferably a modem, devised to transmit said channel identity information together with timing data for the selection of said channel over a communication connection 11 to an external storage medium 12, handled by a central computer.

Figure 2 shows an embodiment with the corresponding units, but where the signal data 27, 28 to the TV set are transmitted via the measurement box 13. This makes the connection of other sources to the measurement box possible, and the possibility to toggle between these sources with a simultaneous detection of which source is feeding the TV set 7 with data. Also the embodiment according to figure 2 is suitable when the STB 1 lacks a teletext decoder. In this case it can be supplied to the system by way of the measurement box 13.

In figure 3 another embodiment is shown, where the STB 1 and the measurement box 13 are integrated. Function blocks in the measurement box and the STB can then be devised as program objects in a common computer system.

Finally, in figure 4 an embodiment of the invention is shown where both the STB 1 and the measurement box 13 have been integrated in the TV set 7. Alternatively, either only the STB 1 or only the measurement box 13 can of course be devised integrated in the TV set 7. Unless stated otherewise, the invention is described further in the example of a preferred embodiment, with simultaneous reference to figure 5. The corresponding units in the figures 1 - 5 have the same reference designation.

The means of the method is mainly to modify the operating system for the STB's 1 internal computer system 30, making it possible to read trace outputs from a communication interface available on the STB, preferably a serial port 31. These trace outputs contain all the information about what the STB 1 sends to the household TV set 7 and can thereby be read and stored in a data gathering unit 9 devised in the measurement box. The invention thus offers a system and a method which, in a way simplified compared to the patents mentioned above, can obtain what each individual in a household views by way of the household TV sets, concerning digital TV. Viewing can mean watching different types of media presentable on the TV set 7, i.e. TV programs, teletext, interactive services for e- commerce, electronic program guide (EPG), etc.

One embodiment also comprises an analogue tuner 34 in the measurement box 13, or connected to it, whereby it is also possible to measure the viewing of analog TV. The digital viewing is thus obtained by using in the chosen measurement households a set top box devised with a software which makes an output of every media type change, i.e. TV, teletext, interactive services, etc, and every change of what in this patent application is called a channel within each media type, respectively, i.e. a TV channel for TV, teletext page for teletext, etc, at the time of change as an output through one of the set top box's serial ports 31. Preferably the special software is designed so that the computer system 30 detects a media type change or channel change, and as a response to the change outputs an address code for the data gathering unit 9, on said serial port 31, followed by the current media type to which the change was made or within which the channel change was made, and the current channel within current media type to which channel a channel change has been made. This is described further below. From said serial port 31 these outputs are read into the data gathering unit 9 and stored in a memory unit 35 devised therein, together with the time when the change was made. The time is preferably obtained from a clock 32, devised in the data gathering unit 9, or from an input 32 for a connectable clock pulse generator.

The measurement box 13 then calls, by way of a modem 10, a central computer with storage capacity 12, once or more each day, and delivers the information stored in the measurement box 13 to be stored in the central computer. Alternatively, the central computer is devised to call the modem to request and get the stored data. The transmission can be made over a communication connection 11 which either comprises the present telecommunication network of the household, the GSM-net or another suitable carrier. The individual information about the spectators, i.e. the media audience or the media users, is obtained by the individual user logging on to the system by way of a remote control 23 especially adapted to the measurement box 13. When the TV set 7 is turned on this is detected by a probe 20, alternatively as a potential given on the TV's scart output, communicatively connected to the computer system 14 of the measurement box 13, which computer system 14 is devised to control the data gathering unit 9 and the other units comprised in the measurement box 13. At a detected power on of the TV set 7 the computer system 14 activates an image communication device 21, a so called On-Screen-Display device (OSD). The OSD is devised to superpose or replace the video data selected for presentation on the TV set with preset text. Thus the login, which is described in detail below, is done by following the instructions showing on the TV screen 22 when the TV set 7 is turned on. Input of login information is done by the individual person or persons by means of the remote control 23, and the measurement box 13 registers the login information by a receiver 24 applied on the measurement box 13 and stores it in the memory unit 35. The communication between the remote control 23 and the measurement box 13 can be done by way of IR or radio, e.g. bluetooth, or by way of another possible carrier.

The advantages of the proposed method are several. Among other things it gives the possibility to obtain information about which interactive services the household uses. Furthermore measuring and storage of both analog and digital viewing and interactive services in the same unit, are made possible. When it comes to the sources of the broadcasts the measurement box 13, by way of plug-in modules in the hardware or software, can catch both VHF and UHF, terrestrial broadcasts, broadcasts by cable, microwaves or DBS direct broadcasts (direct broadcasts by way of satellite) and digital signals regardless if the signal is coded or not.

Also the measurement box 13 can measure interactive systems, and by supplementing it with hardware and software, also e.g. video viewing or the use of a TV game console. In one embodiment, the measurement box 13 comprises a switch 15, which has an input 33 from the media data 27,28 selected and decoded in the STB 1. This data also is preferably analog converted. The switch 15, which is controlled by the computer system 14, furthermore has an inport 17 connectable to an external source, e.g. a video player or DVD 25. Yet another port 18 on the switch 15, in the illustrated example, is connected to the built-in analog tuner 34 which in turn receives signals from a source 26, e.g. an ordinary TV broadcast station for analog TV. The switch 15, which is capable to choose to receive media data from STB 1, or some of the other sources 25, 26, is preferably implemented in the software of the computer system 14 of the measurement box 13, which computer system 14 comprises a processor with an associated memory, I/O and an operating system.

The data gathering unit 9 of the measurement box immediately registers the channel received by the TV set, by way of the detecting device 8 in the STB 1, which detects channel changes or media type changes and makes trace outputs. This should be compared to existing analogue systems on the market where the limit often is set to 15 seconds, which is also the most common in Europe. This means that a channel has to be set for at least 15 seconds without a break before it is registered. Therefore the present invention will further contribute to raising the precision of the measurements. Of course TV companies and other interested parties are interested in receiving information about which TV channels or similar the viewers have watched for a short period of time, and depending of what they saw rejected said channel.

Associated with each measurement box 13 delivered to the households is a remote control 23, which the household members use to register their own personal viewing. On the remote control 23 each household member has his or her own key. When a panel member starts viewing he or she is asked, by way of text message generated by the OSD 21 on the screen 22 of the TV set 7, to press his or her own key to state that it is she or he who is viewing. When the viewer has pressed the key, the name is shadowed and a welcoming message, e.g. "Hello Anna!" is shown. At the same time the members of the family are also asked to login. This message has two functions. First, it works as a quality check to see if Anna pressed the correct key and it gives her the possibility to correct any possible mistake; second, it gives a more gentle impression of the measurement box in relation to the viewer. The measurement box 13 refers to the viewer as a person rather than a figure or a letter. When the viewer wants to stop viewing, she presses her key again and a goodbye message is shown. Also the measurement box can be programmed with special messages like Happy Birthday or Merry Christmas.

Guests viewing TV in the household are also registered. In the panel members' manual, guests are also asked to register their viewing by pressing a key on the remote control which is not pre-programmed. By way of the screen 22 the guest is asked to register sex and age. This information is then included when the calculations of the TV ratings are made. The quantity of guests viewing can vary between different times of the day but can be an important addition to the total viewing during certain times of the year as e.g. Christmas or during large sport events. The guests' viewing is used as a surrogate measurement for panel members viewing TV outside their own home.

The remote control 23 is best devised as a traditional remote control with 10 (0-9) keys for registering viewers. In practice, this makes it possible for any number of people to be logged in by way of the same remote control. As many as necessary are used for the permanent members of the household and the rest for guests.

The measurement box 13 is preferably programmed to remind the viewer at preset intervals to check that all persons present in a room with a turned on TV 7 have registered. This reminder about registration can be programmed to take place e.g. every 45 minutes or at certain occasions like channel changes, to guarantee maximum co-operation from the media users, i.e. the TV viewers, the users of an interactive application, the participants in a TV game, etc.

The TV audience measurement system according to the present invention is designed so that not only TV viewing can be registered. The new technique makes it possible to measure and register the use of teletext regarding channel and page and other interactive events like video-on-demand, e-commerce etc by way of the STB 1. In case the STB 1 does not have a teletext decoder 19, such a decoder can be devised in the measurement box 13.

Downloading registered viewer data, which comprises ID information about the viewers, choice of channel and media type and the times for changing channels and media types, is preferably made at night. The measurement box 13 contacts, by way of the modem 10, a reading system installed on a server over the telephone lines 11 during the night. There the downloaded information is also stored in a suitable storage medium 12. Preferably the download takes place sometime between 2 a.m. and 5 a.m. If the measurement box 13 for some reason fails to get in contact with the server at the first attempt, further attempts are made during the period. The measurement box's 13 modem 10 is also devised to detect when a member of the household starts a telephone call. Then the measurement box immediately transfers the control of the household telephone line and thus lets the call through. When the call is finished, the measurement box detects this and regains control over the line so that the dial-up can proceed. When the measurement box senses an incoming call, which does not emanate from the reading system, it lets go of the line to allow the call to be received and finished. The TV measurement box is designed to minimize losses or distortion of data and to report possible data losses. Output to the serial port is only made when the STB has accepted the connected unit as a measurement box according to the present invention. The measurement box should therefore send a unique start sequence to the STB. The start sequence preferably comprises a start code and a unique identifying code, e.g.

START:XXXX, where XXXX is a unique 16 bit identity number.

In one embodiment, the STB 1, according to the present invention, is devised with an encryption algorithm, equivalent to an encryption algorithm devised in the measurement box 13. When the STB 1 is powered up, the STB 1 generates a cipher key and transmits it to the data gathering unit 9. This runs the cipher key through the encryption algorithm devised in the computer system 14 of the measurement box 13, and sends a return message to STB 1. In STB 1 the return message is checked, and if the measurement box 13 is recognized, the STB 1 lets through said trace output to the port 31.

The measurement box registers viewing or a change in the viewing immediately when the action takes place. Each registration is established back in time to the time when it actually took place, down to the nearest tenth of a second. The minute of the clock is used as a measuring unit. A certain minute is assigned the value of the channel, to which the TV set was set during the longest period of that minute. For individual persons registered changes means the beginning or the end of all viewing that takes place and which has to continue for at least 0,1 second to be reported. Each legitimate registration is established to the time when it actually took place, down to the nearest tenth of a second. A TV channel or another operator is assigned the viewing of an individual person if he or she is registered for more seconds during a given minute compared to a competing channel or activity. According to the present invention the system software for the STB differs from the prior art in that the STB at each media type change sends an information string to its serial port 31. The system software specific for the invention is achieved in one embodiment by a change in the existing software of the STB, by a patch being made in the existing system software. In an alternative embodiment the system software is written directly for the invention, and is applied directly in the STB by the box manufacturer.

By media type, different types of media which can be conveyed by way of the media presentation unit to which the set top box is communicatively connected, are understood. For the example TV the media presentation unit is a TV set comprising a screen devised to show moving pictures, and preferably a loud speaker to play the accompanying sound. Different types of media which can be conveyed by such a TV set are TV programs, teletext, interactive services, electronic program guide, analog video, DVD, etc. When someone presses the remote control 36 for transmission of media type selection data to the receiver 37 of the STB 1, consequently a string is sent out on the serial channel 31 as described below. Furthermore, the invention allows information about a channel change within a certain media type to be detected. By channels are meant, inter alia, a TV channel for the example TV, teletext page for the example teletext, given instructions, ordered services and suchlike for the example interactive applications, etc. Thus a media type change for example can be the activation of teletext, and then the selected channel is the teletext page which the viewer demands with his or her remote control. In certain existing set top boxes other debug information can flow from the serial channel, in which case you have to establish an ID for the measurement box 13 which is sent according to a special pattern at a channel change or media type change. Below some examples of different embodiments of what the data string sent from the set top box to the measurement box can look like depending on media type, are presented.

- TV viewing. When the panel member, i.e. a viewer, chooses the media type TV, or chooses a new TV channel, the following string is sent to the serial channel: "Mbox:XXYYYYQQQQZZZZPPPP <cr>" xx TV (Channel change) yyyy Service type qqqq Service ID zzzz Original Network ID pppp Transport Stream ID

- Teletext viewing. When the panel member chooses the media type teletext, or chooses a new teletext page, the following string is sent to the serial channel: "Mbox:XXYYYYZZZZ <cr>" xx TX (Teletext) yyyy Page zzzz Possible subpage (e.g. Germany)

- Interactive programs such as e-commerce. In the world of digital TV the network operators as a rule are responsible for their own interactive applications. When a viewer chooses to change TV channel, let us say from TVl to TV3, the STB automatically receives the software code for that channel's current interactive application, and stores it in a dedicated memory in the STB. If the previous channel TVl also permitted interactive applications, the memory is purged with the software for this previous application when the interactive application of the new channel is downloaded into the STB. Also the interactive application for a given channel currently showing on the TV set can be updated or changed, for example when a new TV program starts. Also in such cases the memory is updated with the new or changed application from the network operator. Said memory can comprise a flash memory, RAM or a harddisk.

The software of the interactive application is, as a rule, sent to the STB over the same medium as the TV code itself, i.e. by way of a satellite, cable etc. Interactive applications allow communication from the viewers to the STB, different so called traces, preferably by way of the belonging remote control, e.g. for ordering goods or services, or to share certain information. The STB usually uses the TV screen to communicate control data and other information to the viewer, to inform him or her about how the interactive application can be used with the remote control, for example how the ordinary numeric keys are interpreted as instructions by the STB.

A simple interactive application devised to convey certain information, e.g. a course guide during a TV broadcast of a golf tournament, can be run purely as a communication between the STB and the viewer, since all data that can be chosen and presented is already downloaded into the STB from the network operator. A more advanced interactive application allows the connection by way of external communication networks, e.g. Internet or a broadband net with a dedicated server. The connection to such a data communication network can of course be made by way of the TV cable, or by way of a separate connection to the telecommunication network by way of a modem, or a broadband output. This is preferably achieved through a portal belonging to the network operator, and of course grants an almost infinite source of interactive services. Yet another type of interactive application, which as a rule is permanently devised in the set top box, is the transmission of information data to the TV set, the information data of which represents for example channel identity, and which is presented as a sign or a message on the TV screen. Thus this interactive application is devised to detect media type choice or channel choice conveyed by the user's remote control, and as a response to the detected choice, change to the selected media type or channel, as well as arranging it in a manner so that a change to the selected setting is presented on the TV screen when executed. In the simplest case, this means e.g. that the viewer orders a change from TVl to TV4 by way of the remote control to the STB. This is detected by the STB, which changes from transmitting decoded data for TVl to transmitting decoded data for TV4 to the TV set. Furthermore the STB sends information data to the TV set, which is presented on the TV screen as a figure "4". When the viewer wishes to activate an interactive service on the TV channel being viewed, this is preferably done by activating it with the remote control, spontaneously or as a response to an invitation from the STB in the form of a short message presented on the TV screen, e.g. "press OK". When the viewer activates the interactive application, or gives instructions with the remote control within the interactive application, the system software is devised to send the following string on the serial channel: " Mbox:XXYYYYYY <cr>" xx IN (Interactive) yyyyyy Different trace numbers

- EPG (Electronic Program Guide). Also this media type is activated by means of the STB remote control. The following string is sent on the serial channel when the viewer activates the EPG or gives instructions with the remote control within EPG: " Mbox:XXYYYYYY <cr>" xx EP (EPG) yyyyyy Different trace numbers.

Since the invention allowes the detection and output of both a media type change, represented above by xx, and channel change within a certain media type, represented above by combinations comprising y, q, z, p, a system is obtained, which is superior to all known audience measurement systems. The STB's capacity is used to a maximum since it controls what is shown on the TV screen whereby this data can be fetched therefrom, at the same time as the interference with the current software and memory of the STB is kept at a minimum. The data already detected by the STB, i.e. the instructions given by the remote control, is output as short data strings on the already existing serial port, and the data in the strings are then stored in a separate measurement box connected to said serial port. From this measurement box the data is later on transmitted to a central computer for storage and processing for the purpose of interpreting the audience's viewing habits. It is the responsibility of the STB to report certain events to the measurement box by way of the serial interface and, in one embodiment, of said box to time stamp and record these reports. Different events that are to be reported are either Requests - events initiated by the viewer, or Responses - events which occur in the STB as a result of a request.

Simply the request (req) can be defined as being when the viewer orders the STB to perform a complex event such as powering up or down, changing channels, initiating/navigating/ending applications, initiating/navigating/ending teletext, establishing/ending communication sessions etc. When changing channels "Prog +" and "Prog -" generate requests immediately. For example, if the viewer wants to specify channel 12 using the sequence "1", "2" and "Ok" the request is generated after the "Ok" button has been pressed (or after the "next button timeout" or equivalent occurs).

In contrast, the simple event is something which does not cause a complex event to occur such as a movement of a cursor initiated by the mouse/trackball without pressing a button, entering text in an e-mail without sending it, pressing numeric keys in sequence before the "next button timeout" or equivalent occurs, etc.

The response (rsp) varies with the request. In one embodiment the response to a power up request is information about operator, box manufacturer, hardware version, software version, smart card id(s). In another embodiment the metering functions in the STB are unlocked by an encoded request from the measurement box, or metering box. Sometimes when powering up, the STB asks the viewer whether he/she wants to upgrade the STB software which is another req/rsp. After the upgrade has been accepted or rejected the STB sends the current channel (the same number which is displayed on the STB's front panel) followed sometime later by the current service type, original network id, transport stream id and service id (SOTS) report. Why are these different reports? On certain STBs changing channels causes the screen to freeze and quite a bit of time passes before the new channel is displayed correctly. Because the screen freezes it is not incorrect to say that what is displayed on the frozen screen should be regarded and classified differently from what was displayed before the channel change (even though it is from the same channel) and what is displayed after the channel change has been completed. When entering teletext the request is reported as entering teletext. When the first page is displayed the current teletext page response occurs. When the viewer requests a new page the "new teletext page" request is generated later followed by the current teletext page response.

According to one embodiment of the invention, the format of a request or a response is generally as follows. A variable length ASCII text message of length n terminated by a Carriage Return (ASCII OxOd) followed by a Line Feed (ASCII 0x0a). The first three (0-2) characters of the message denote the message type and contain either "REQ" (for request) or "RSP" (response). The following three (3-5) characters contain function type such as "BOX" (power on/off), CHN (current channel/SOTS), TTX (teletext), ETV, EGD (electronic guide), TVP (TV portal), IAP (interactive application), MDM (modem) etc. Characters 6-8 contain event type such as ENT/EXT (power on/off for BOX function, enter/exit, begin/end etc.). There is DIA DIS/HUP/TNF (dial/connect/fail/disconnect/hangup) for modem, SEL/CUR for select/current request/response pair (CHN or TTX channel/page SELect request followed by CHN or TTX CURrent SOTS/page response).

Certain messages are not longer than eleven characters (the first three groups followed by CR/LF). Examples of such messages are REQBOXENT (,- EXT) , RSPMDMDIS (-HUP), RSPBOXEXT, etc.

When the messages need to be longer the first nine characters are followed by a colon ":". Next is a text or texts containing additional information as required. If necessary (exclusively when the lengths of the fields are unknown) this information is divided into subfields using a comma ",". An example of this is the RSPBOXENT text information. The length of the RSPCHNCUR SOTS information, on the other hand, is known in that it consists of four four-digit groups. In that case the entire report length is 9+l(colon)+4*4(SOTS)+2(CR/LF)=28 characters.

One example of a simple power on, software update, channel select, teletext and power off sequence is described below for an embodiment of the present invention.

Viewer STB Comment presses power on REQBOXENT(CRLF) (main display switched on, short delay)

RSPBOXENT(CRLF) (software update screen)

RSPBOXINF:Boxer,terrestrial,Sag em ITD

44110,461000235152,3245063899

7 presses "Ok" REQBOXSWU(CRLF) (software is updated)

RSPBOXSWU(CRLF) (latest/other channel displayed)

REQCHNSEL:0001(CRLF) (short delay)

RSPCHNCUR: 1111222233334444

(CRLF) presses "Prog +' REQCHNSEL:0002(CRLF) (short delay)

RSPCHNCUR: 1111222233335555

(CRLF) presses teletext REQTTXENT(CRLF)

RSPTTXCUR-.O ΙOO(CRLF) presses "Prog +" REQTTXSEL:0101(CRLF)

RSPTTXCUR:0101(CRLF) presses X (or TV) REQTTXEXT(CRLF)

RSPTTXEXT(CRLF) presses power off REQBOXEXT(CRLF) (shuts down)

RSPBOXEXT(CRLF) (main display switched off)

Fields which preferably should be defined include:

RSPIAPINF (comma-separated) information (creator, advertiser etc.) REQIAPSEL report of user action (button pressed etc.) RSPIAPCUR report of application action (screen which is being displayed etc.) REQETVSEL similar to REQIAPSEL RSPETVCUR similar to RSPIAPCUR REQMDMDIA contains phone #

Different report headings are:

Request Responsefs) Comment REQBOXENT RSPBOXENT REQBOXENT is not mandatory. RSPBOXLNF:...

REQBOXSWU RSPBOXSWU REQBOXEXT RSPBOXEXT

REQCHNSEL:... RSPCHNCUR:

REQTTXENT RSPTTXCUR:

REQTTXSEL:. RSPTTXCUR:

REQTTXEXT RSPTTXEXT

REQETVENT RSPETVENT

REQETVSEL:. RSPETVCUR:

REQETVEXT RSPETVEXT

REQTVPENT RSPTVPENT REQTVPSEL:. RSPTVPCUR: CUR may show IP or URL REQTVPEXT RSPTVPEXT REQEGDENT RSPEGDENT

REQEGDSEL:... RSPEGDCUR:

REQEGDEXT RSPEGDEXT

REQIAPENT REQIAPEXT

REQMDMDIA:.. RSPMDMINF:... REQMDMDIS RSPMDMHUP

Different report subclasses are presented below, wherein sections enclosed in brackets "[ ]" denote optional items not essential to the system functionality.

Characters

0-2 3-5 6-8 Comment

REQ Generated by box on external input

RSP Generated by box as response to a REQ

BOX - Box status and other information (BOX subtypes)

INF:.. , . ~ operator, media[,box manuf/id,box s/n,card id(s)]

SWU -- Box software update begin request/ended response

CHN - Channel change

EGD - Electronic guide

ETV - eTV

IAP - Other (third-party) interactive application (IAP subtypes)

INF:.. . ~ creator, iap id#, advertiser, campaign info, ...

MDM - Modem (MDM subtypes)

CON — Modem connected response

DIS -- Begin hangup request

HUP ~ Hangup completed response

INF:.. . ~ Single-digit result code of Hayes type

TTX - Teletext

TVP - TV portal (Generic subtypes)

CUR:. — "Current state" response to select request

ENT ~ "Enter" power on, start application, begin teletext

EXT ~ "Exit" power off, end application, end teletext SEL:... - "Select" request

IAP reports ENT and EXT are handled within this specification. IAP reports INF, SEL and CUR are preferably generated within each interactive application which writes directly to the serial port interface.

Preferred embodiments of the invention have been described in detail, but only represent examples of what can be implemented within the concept of the invention. It is evident for a person skilled in the art that the embodiments can be modified within the scope of protection, which is limited only by the appended claims.

Claims

1. A system for media audience measurement, comprising:

- a data receiving unit (1) with a first input (2) for an incoming digital coded data stream (3), a selection device (4) for extracting media data associated with a selected media type from said data stream, a decoding device (5) for decoding extracted data;

- a controller (36) for controlling the selection device to change media type;

- a media presentation unit (7) for presentation of extracted and decoded media data; - a detecting device (8) devised to detect a change of selected media type which is presentable in the media presentation unit, and to output a data string for the selected media type on a serial channel of the data receiving unit;

- a data gathering unit (9), connectable to said serial port, devised to store data output from the serial port in combination with timing data.

2. The system according to claim 1, where said controller comprises means for controlling the selection device to, for a selected media type, extract media data for a given media channel, and where said detecting device is devised to detect a change of selected media channel and to output a data string comprising data for selected media channel.

3. The system according to claim 1, where said media presentation unit is a TV set, where different media types presentable on the TV set and detectable by said detecting device comprise TV programs and interactive applications stored in said data receiving unit.

4. The system according to claims 2 and 3, where for the media type TV said media channel represents a TV channel, and for the media type interactive applications said media channel represents a trace, selectable with the control device, for the current interactive application.

5. The system according to claim 3, where said presentable and detectable media types further comprise teletext.

6. The system according to claims 2 and 5, where for the media type teletext said media channel represents a teletext page.

7. The system according to claim 1, further comprising a communication unit (10), connectable to said data gathering unit and devised to transmit data stored in the data gathering unit to an external storage medium (12) by way of a communication connection (11).

8. The system according to claim 1, where said detecting device is devised in the operating system of a computer system (30) comprised in the data receiving unit, the detecting device of which comprises means to detect identity data at a media type change for the new media type in the media data decoded by the decoding device, and means to comprise said in said string.

9. The system according to claim 1, where said data gathering unit comprises a clock device (32), devised to deliver said timing data.

10. The system according to claim 1, where a measuring device (13) comprising said data gathering unit further comprises a computer system (14) and a data stream switch (15) with a first input (33) devised for input of decoded media data from said decoding device, and a second input (17,18) for input of media data from an alternative media source (25,26), which data stream switch is controlled by said computer system.

11. The system according to claim 1, where said presentation units comprises a sensing device (20) adapted to sense when the presentation unit is turned on and give a power up signal thereupon.

12. The system according to claim 11, where an image communication device is devised, depending on said power up signal, to present a login message on said screen.

13. The system according to claim 12, further comprising a data input device (23) devised for communication with a data receiving device (24) communicatively connected to said image communication device, which data input device comprises means for entering login data.

14. A system for media audience measurement, comprising a TV set, a set top box for digital TV connected to the TV set, a remote control for the set top box for the selection of media data to be presented on the TV set, and a data gathering unit connected to a serial port on the set top box, wherein the set top box comprises means to convey different media types to the TV set comprising TV programs and interactive applications, and means to detect change of media type for selected media data, and thereby send a data string with address for the data gathering unit to the serial port comprising information about the selected type of media data.

15. A system for media audience measurement, comprising a TV set, a set top box for digital TV connected to the TV set and comprising means to convey media data of different media types and for different media channels within said media types to the TV set, a remote control to the set top box for the selection of media data to be presented on the TV set, and a data gathering unit connected to a serial port on the set top box, wherein the set top box comprises a computer system devised to send for each change of selected media type a string of data to the serial port, which string comprises a code representing the selected media type, and to send for each change of selected media channel a string of data to the serial port comprising a code representing the selected media channel.

16. The system according to claim 15, where said media types comprise TV programs, for which media type said media channels represent TV channels, and interactive applications, for which media type said media channels comprise different traces in the application.