Abstract:
A method of distributing video data comprising defining a plurality of programme elements, each programme element comprising a video clip taken from said video data. Each programme element is allocated to one of a predetermined plurality of classes, each class having an associated icon. Data representing a plurality of icons is transmitted to a receiver, each icon representing a class to which a respective one of said plurality of programme elements is allocated. User selection data indicative of a user selection of at least one icon is received, and data associated with the or each programme element associated with the user selection data is transmitted to the receiver. A method for generating video data, and a method for presenting video data are also disclosed.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     Great Britain Priority Application 0405340.1, filed Mar. 10, 2004 including the specification, drawings, claims and abstract, is incorporated herein by reference in its entirety. Great Britain Priority Application 0408124.6, filed Apr. 13, 2004 including the specification, drawings, claims and abstract, is incorporated herein by reference in its entirety. 
     FIELD OF THE INVENTION 
     The present invention relates to a method and apparatus for distributing video data. The invention also relates to a method and apparatus for receiving video data, a method and apparatus for presenting video data, and a method and apparatus for generating video data. 
     BACKGROUND OF THE INVENTION 
     Video data is currently distributed in a variety of different ways. For example, video data is transmitted in the form of broadcast television programmes which are received by a user and displayed using a television receiver. In recent times, such television programmes have been distributed by means of satellite transmissions and cable lines, in addition to more traditional radio frequency transmissions. Furthermore, it is well known to distribute recorded video data on storage media such as video cassettes and Digital Versatile Disks (DVDs). 
     Recently, the Internet has increasingly been associated with the distribution of video data. Software to display video data is readily available for conventional personal computers, but many users suffer from problems of bandwidth. For example, users connecting to the Internet via a modem and a dialup connection to an Internet Service Provider experience low data transmission rates, making real-time video very difficult to achieve, with displayed video having artefacts of “jerkiness” which is most disconcerting to a user, and impairs enjoyment of the video data. Similar problems exist when a mobile device such as a mobile telephone or handheld computer is used to access video data. Given these problems, many users download an entire broadcast, and then watch the downloaded broadcast. This is again disadvantageous, because this downloading can typically take many minutes to complete. 
     Even users using high bandwidth connections (generally known as “broadband” connections) can still encounter problems when high quality video data is involved, with the undesirable effects described above being experienced. 
     U.S. Pat. No. 6,647,535 (Xerox Corporation) describes a system for creating a storyboard from video data. The storyboard comprises a plurality of still images which are representative or key frames taken from the video data. The selected still images can then be displayed to a user by means of an Internet webpage, and a user can select one of the still images to cause a video clip associated with that image to be downloaded and displayed. Although this proposal provides a way of encapsulating a video clip by means of a relatively small number of still images, it suffers from some disadvantages. For example, using still images taken from the video data will not necessarily provide a meaningful and easily understandable indicator of the programme content of the associated video data. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to obviate or mitigate at least some of the problems described above. 
     The present invention provides a method and apparatus for distributing video data. The method comprises defining a plurality of programme elements, each programme element comprising a video clip taken from said video data. Each programme element is allocated to one of a predetermined plurality of classes, each class having an associated icon. Data representing a plurality of icons is transmitted to a receiver, each icon representing a class to which a respective one of said plurality of programme elements is allocated. User selection data indicative of a user selection of at least one icon is received, and video data associated with the or each programme element associated with the user selection data to the receiver. 
     The invention also provides a method for receiving video data comprising a plurality of programme elements. Each programme element comprises a video clip taken from said video data, and each programme element is allocated to one of a predetermined plurality of classes, each class having an associated icon. The method comprises receiving data representing a plurality of icons, each icon representing a class to which a respective one of said plurality of programme elements is allocated. A user selection is received and user selection data representing said selection is transmitted. Data associated with the or each programme element associated with the user selection data is received. 
     By defining a plurality of programme elements, and allocating each programme element to a class having an associated icon, a distributed video clip can be represented by a series of icons arranged in temporal order of the associated programme elements in the video data. Using icons associated with predetermined classes provides a method of presenting a user with a structured and easily recognised summary of a video clip, with each icon being easily identifiable. 
     At least some of said plurality of classes may represent a type of event, a programme element may be allocated to one of the plurality of classes on the basis of an event to which the video clip relates. At least some of said plurality of classes may represent a subjective assessment of the value of programme elements and a programme element may be allocated to one of the plurality of classes on the basis of a subjective assessment of value. 
     The icons may be arranged in an order corresponding to a temporal order of the programme elements represented by the icons. Transmitting data associated with the or each programme element associated with the user selection data to the receiver may comprise transmitting the or each programme element to the receiver. 
     At least one of said programme elements may comprise a plurality sub-elements, each sub-element may be allocated to one of a predetermined plurality of sub-classes, and the method may further comprise transmitting a further plurality of icons to the receiver in response to selection of an icon associated with the said at least one programme element, each further icon representing a class to which a respective one of said plurality of sub-elements is allocated. Selection data indicative of a user selection of at least one icon corresponding to one of said sub-elements is received, and data associated with the or each sub-element associated with said selection data is transmitted to the receiver. 
     The present invention also provides a method of presenting video data. This method comprises displaying a first identifier identifying a stream of video data. The video data comprises a plurality of programme elements, each of which has been allocated to one of a predetermined plurality of classes. First user selection data is received indicating a wish to condense the video data and said first user selection data comprises data indicative of user preferences. The video data is condensed in accordance with the first user selection data, to produce condensed video data. The condensed video data comprises a subset of the plurality of programme elements selected on the basis of the first user selection data. The condensed video data is displayed. 
     Presenting video data in this way provides a convenient mechanism for a user to extract only content of interest from video data, thereby avoiding the need to view content of little or no interest. For example, if video data is allocated to classes at least partially on the basis of event type, condensed video data can be generated by removing video data associated with a specified event type, or alternatively removing all video data except that associated with the specified event type. 
     The method of the invention is also useful for extracting highlights from video data. For example, where video data is allocated to classes at least partially on the basis of a subjective value judgement such as interest level, a user can specify that only content of a relatively high interest level is to be viewed. This can be useful where it is desired to view highlights of video data in a shorter time than that occupied by the entire video data. 
     The invention also provides a method of generating video data. The method comprises storing video data as a plurality of programme elements, each programme element being allocated to one of a predetermined plurality of classes. First input data indicating classes of said predetermined plurality of classes which are of interest to a user is received. Second input data indicating an approximate desired viewing duration is also received. Programme elements are retrieved from said stored programme elements in accordance with said first input data, to generate video data having a viewing duration substantially equal to the desired viewing duration. 
     Generating video data in this manner allows relatively long duration viewing data to be condensed so as to be viewable within a time available. The condensing can be carried out to include events having a relatively high interest level. A user may specify an ordered list of preferences, indicating a range of desirability of various video data, and video data of relatively high desirability may be included in preference to video data of lower desirability. 
     It will be appreciated that the method of presenting video data, and the method of generating video data described above can be carried out either locally at a client terminal, or alternatively in a distributed manner whereby the client communicates with a remote server, and it is the remote server which carries out the condensing. The implementation of such distributed embodiments of the invention will be readily apparent to one skilled in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
         FIG. 1  is a schematic illustration of a computer network suitable for implementing an embodiment of the present invention; 
         FIG. 2  is a flow chart showing a video classification and distribution process in accordance with an embodiment of the present invention; 
         FIG. 3  is a schematic illustration of video data classified using the process of  FIG. 2 ; 
         FIG. 4  is an illustration of icons representing the classification illustrated in  FIG. 3 ; 
         FIG. 5  is a flow chart showing a video receiving and displaying process in accordance with an embodiment of the present invention, which is suitable for using with the classification and distribution process of  FIG. 2 ; 
         FIG. 6  is a schematic illustration of a class hierarchy which can be used for classification in accordance with an embodiment of the present invention; 
         FIG. 7  is an illustration of icons representing a hierarchical classification in accordance with the present invention; 
         FIG. 8  is an illustration of icons representing a soccer match; 
         FIG. 9  is an illustration showing a subset of the icons of  FIG. 8 ; and 
         FIG. 10  is an illustration of a display screen which can be used in embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , there is illustrated a video server  1  connected to the Internet  2 . Two workstations  3 ,  4 , a laptop computer  5  and a mobile telephone  6  are also provided with means for connection to the Internet  2 . The workstations  3 ,  4  and the laptop computer  5  can be connected to the Internet  2  via a modem and telephone line (not shown), or alternatively via a connection to a local area network (LAN) which is itself connected to the Internet  2 . The mobile telephone  6  can be connected to the Internet  2  either by means of a dialup connection using the Wireless Application Protocol (WAP) or alternatively the mobile telephone  6  can be a third generation mobile telephone with Internet access capability. Indeed each of the user devices  3 ,  4 ,  5 ,  6  can be connected to the Internet  2  in any one of a number of ways which will be readily understood by one of ordinary skill in the art. 
     A user using the mobile telephone  6  can use web browser software installed on a computer readable storage medium of the mobile telephone to access a web page defined in the HTML language provided by the video server  1 . The web page suitably includes options allowing the user of the mobile telephone  6  to view video data stored on the video server  1  using suitable video player software installed on the mobile telephone  6 . The video data stored on the video server  1  has, in accordance with an embodiment of the invention, been classified as is now described. 
       FIG. 2  is a flow chart of a classification process for video data which may be carried out by a user of the video server  1 . A user processes video data at step S 1 , and a plurality of programme elements within the video data are defined at step S 2 , and classified at step S 3 . Programme elements will typically relate to discrete events within the video data. 
     Classification of a news programme  7  is illustrated in  FIG. 3 . The news programme extends from a time t 0  to a time t 7 . Seven discrete programme elements are defined within the news programme  7 . A first programme element  8  starts at time t 0  (that is the beginning of the news programme  7 ), continues until time t 1  and relates to a kidnap story. A second programme element  9  extends from time t 1  and continues until time t 2 . This programme element relates to a news item describing a US presidential visit. A third programme element  10  begins at the end of the second programme element  9 , (that is at time t 2 ), continues until time t 3  and relates to a prime ministerial scandal. A fourth programme element  11  relates to a jail break, and extends from time t 3  to time t 4 . A fifth programme element  12  extends from time t 4  to time t 5  and relates to university tuition fees. A sixth programme element  13  relates to financial news, and extends between time t 5  and time t 6 . A seventh programme element  14  relates to weather news and extends from time t 6  to the end of the news programme  7 , that is to time t 7 . 
     Referring back to  FIG. 2 , at step S 2  an operator places markers at each of times t 0  to t 7  to delimit the seven described programme elements illustrated in  FIG. 3 . At step S 3  each programme element is allocated to one of a predetermined plurality of classes. In this example these classes relate to content type, and more particularly to the nature of the news story represented by each programme element. 
     Classification of video data is described in the applicant&#39;s published PCT patent application, (publication number WO99/03275) the contents of which are herein incorporated by reference. The applicant&#39;s published U.S. patent application (publication No. US2004/0070594 application Ser. No. 10/435,178) also describes methods for classifying and manipulating video data, and its contents are also herein incorporated by reference. 
     Classification can suitably be carried out by an operator viewing the video data within a graphical user interface (GUI), the GUI providing a plurality of icons which can be selected to effect classification. The user selects a type of programme to be classified (in this case news) and is presented with a plurality of icons which represent programme elements expected to occur within a news programme. The video data is viewed by the operator, and as each new programme element begins, an icon representing the content of that programme element is selected (thus steps S 2  and S 3  of  FIG. 2  could be carried out concurrently). Preferred embodiments of the GUI provide an operator with functionality to offset delays in selecting an appropriate icon, as compared with the true start of a programme element. The published U.S. patent application referred to above describes a suitable GUI. 
     The classification of each programme element described above is denoted by an appropriate icon.  FIG. 4  shows a sequence of icons which represent the programme elements making up the news programme  7 . A first icon  15  represents the kidnap story programme element  8 , a second icon  16  represents the US presidential visit programme element  9 , a third icon  17  represents the prime ministerial scandal programme element  10 , and a fourth icon  18  represents the jail break programme element  11 . A fifth icon  19  represents the university tuition fees programme element  12 , a sixth icon  20  represents the financial news programme element  13 , and a seventh icon  21  represents the weather programme element  14 . It can be seen from  FIG. 4  that the sequence of icons provides an easily understandable summary of the content of the video data. Furthermore, over time a user will become readily familiar with the various icons which are used, and will therefore almost instantly know the content type of the associated video data. 
     Referring back to  FIG. 2 , having performed appropriate classification, the video server  1  is ready to accept a request from a user via the Internet for the classified video data. Such a request is received at step S 4 . Classification data representing a class to which each programme element within a requested programme is transmitted to a user at step S 5 , via the Internet  2 . This data takes the form of a plurality of codes, one for each programme element, each code indicating the class to which the respective programme element has been allocated, together with a unique identifier of that programme element. The video server  1  then awaits a response from the user at step S 6 . 
       FIG. 7  shows processing carried out by a user device such as the mobile telephone  6  upon receipt of classification data transmitted at step S 5  of  FIG. 2 . At step S 7  the classification data is received and stored within the user device. In the described embodiment of the invention each user device stores the plurality of icons used to represent programme element classification. These icons are suitably transmitted to the user device when no other network activity is taking place and stored. The user device processes the classification data received at step S 7  and corresponding icons are retrieved from storage at step S 8 . Thus, if classification codes representing the programme elements of the news programme  7  are transmitted, the sequence of icons illustrated in  FIG. 4  will be generated, and these are displayed to the user at step S 9  via a suitable display device, which will typically be a monitor in the case of the workstations  3 ,  4 , or a built in screen in the case of the laptop computer  5  and the mobile telephone  6 . A user then reviews the sequence of icons and selects one of the icons. This selection can suitably be made by moving a cursor visible on the display device using an input device such as a mouse to cause selection of one of the icons. Alternatively, the icons can be displayed on a touch sensitive screen, and selection can be effected simply by touching the screen, either with a finger, or with a provided touch pen. Indeed, as will be readily apparent to one skilled in the art, any appropriate input device can be used. User input is received at step S 10  and user selection data indicative of this input is generated at step S 11 . This data can suitably simply comprise the unique identifier of the programme element represented by the selected icon, and is transmitted to the video server  1  at step S 12 . The user device then enters a loop at step S 13  until appropriate video data is received from the video 
     Referring back to  FIG. 2 , on receipt of the user selection data, the loop of step S 6  exits, and the received data is processed at step S 14 . This processing comprises locating video data identified by the unique programme element identifier contained within the user selection data. The located video data is transmitted to the appropriate user device at step S 15 . The video data is transmitted as one or more video data files in any convenient file format such as MPEG, RealPlayer or QuickTime, for example. Referring back to  FIG. 5 , receipt of video data causes the loop of step S 13  to exit, and the user device can then display the video at step S 16  using appropriate video player software. This software can either be a stand alone application, or alternatively can be included within the web browser software used to display the icons for user selection, or included in a web page using, for example, a Java™ Applet. Activation of a suitable standalone video player from a web page and inclusion of a Java™ applet in a web page are well known in the art, and are not described in further detail here. 
     In the embodiment of the invention described above, it has been assumed that icons are already present on the user device, and are retrieved using classification codes transmitted by the video server  1 . In alternative embodiments of the present invention, no icons are stored on a user device in advance, but instead the video server  1  responds to a user request by providing icons together with unique programme element identifiers as described above. Transmission of icons does require slightly greater bandwidth, however this embodiment of the invention makes the described method more widely applicable to devices which do not have stored icons. 
       FIG. 6  illustrates a hierarchy of classes which can be used for multi-layer classification. In the following description the term “channel” is used to refer to a group of video data items (referred to as programmes) containing programme elements which are provided by a common source. The hierarchy of  FIG. 6  has a top level channels class  22  which represents the root of the classification hierarchy. The channels class  22  has five sub-classes which represent channels offering various different content types. A first sub-class  23  is used to represent news channels, a second sub class  24  is used to represent entertainment channels, a third sub-class  25  is used to represent music channels, a fourth sub-class  26  is used to represent travel channels, and a fifth sub-class  27  is used to represent health channels. Each of these sub-classes is used to represent channels of the appropriate type. The News class  23  has sub-classes representing various news channels. A sub-class  28  is used to represent a BBC news channel, a sub-class  29  is used to represent a Sky news channel, and a sub-class  30  is used to represent a CNN news channel. 
     Each of the sub-classes  28 ,  29 ,  30  in turn has sub-classes which represent programmes provided by that channel.  FIG. 6  illustrates three subclasses of the sub-class  29  used to represent the Sky news channel, namely a breaking news class  31 , a six o&#39;clock news class  32  and a travel news class  33 . There are also illustrated subclasses of the six o&#39;clock news class  32  which represent programme elements within that programme. Four sub-classes are illustrated: a political news class  34 , a home affairs class  35 , an international news class  36  and a weather class  37 . Some of these classes have one or more sub-classes. Specifically. The political news class  34  has a prime ministerial news class  38  as a sub-class. The home affairs class  35  has a crime class  39  and an education class  40  as sub-classes. The crime class  39  in turn has a prisons class  41  as a sub-class. The international news class  36  has a US news class  42  and an international finance class  43  as sub-classes. The US news class  42  in turn as a class  44  representing news concerning the US president. The hierarchy of  FIG. 6  includes a number of paths indicated in broken lines. This is simply to indicate that further classes are provided at that level of the hierarchy, but these are not described in further detail here. 
     The hierarchy described with reference to  FIG. 6  can be used to classify data using the video server  1 . As shown in  FIG. 4 , this classification can allow video data to be classified using classes at different hierarchical levels (e.g. the education class  40  represented by the icon  19  is at a higher hierarchical level than the prisons class  41  represented by the icon  18 ). 
     In the embodiments of the invention described above, a single sequence of icons ( FIG. 4 ) has been described, in which a user selects specific video data, and is provided with a sequence of icons representing programme elements which make up that video data. An alternative embodiment of the invention using the hierarchy of  FIG. 6  is now described with reference to  FIG. 7 . A user is initially provided with a sequence of icons  45  which represent different channel types. An icon  46  represents news channels, an icon  47  represents entertainment channels, an icon  48  represents music channels, an icon  49  represents travel channels, and an icon  50  represents health channels. It can be seen that these icons correspond to similarly named classes in  FIG. 6 . 
     On being presented with the sequence of icons  45  a user can make a selection so as to be presented with details of appropriate channels. In the example of  FIG. 7  a user selects the news icon  46 . This selection is communicated to the video server  1 , and in return a further sequence of data is transferred to the user device, for display to the user. This sequence of data is represented by a sequence of icons  51 . The sequence of icons  51  comprises a BBC news icon  52 , a Sky news icon  53 , and a CNN news icon  54 . Again a user selection is made and transmitted to the video server  1 , data is received from the video server  1 , and a further sequence of icons  55  is displayed, representing programmes provided by the selected channel. In this case it was the Sky news icon  53  which was selected, and programmes provided by the Sky news channel are represented by a breaking news icon  56 , a six o&#39;clock news icon  57  and a travel news icon  58 . A user can select one of the icons  55  to cause display of icons representing programme elements. For example, if the six o&#39;clock news icon  57  is selected, the sequence of icons shown in  FIG. 4  is displayed, and user interaction continues in the manner described above. 
     It should be noted that all embodiments of the invention described above are advantageous, given that summary information is provided to the user in the form of a sequence of icons which can be provided by transmitting minimal data. This summary data can be hierarchical as in the case of  FIG. 6 and 7 . Video data is transmitted only when specifically requested. Furthermore, given the classification process, only a small quantity of video data of interest to the user is downloaded, meaning that users having low-bandwidth connections make economic use of that bandwidth. 
     It will be appreciated that he hierarchy of  FIG. 6  is merely exemplary, and other hierarchies could be used. For example in some hierarchies there may be no concept of channels as described above. Instead each programme element may be classified with a hierarchy indicating only features of programme element content, regardless of source. 
     The embodiments of the invention described above have been concerned with classification of programme elements on the basis of programme content. In alternative embodiments of the invention, video data can be divided into programme elements, and each element can be classified on the basis of a subjective value judgment such as an interest level. A programme can then be represented by means of, for example, a sequence of icons, each icon representing an associated interest level by means of a number of stars ranging from zero to five. A user can then simply select one or more icons representing relatively interesting programme elements to cause these to be downloaded in the manner described above. Using icons representing interest level as opposed to content classification may be particularly suitable, for programmes which do not have discrete content based events, but rather contain only a single content type. 
     Some embodiments of the invention use content based classification as described above, in combination with interest level indicators as described above. 
     Embodiments of the invention can be used to allow a user to condense a stream of video data such that it can be viewed within a time which a user has available.  FIG. 8  illustrates part of a sequence of icons which represent a soccer match. Only part of the sequence of icons representing an entire soccer match is illustrated in  FIG. 8 , with omitted icons being denoted by ellipsis. It can be seen that the soccer match is represented by a start game icon  59 , a dribble icon  60 , a defensive action icon  61 , an offside icon  62 , a free kick icon  63 , a further dribble icon  64 , and a goal icon  65 . Icons representing the remainder of the first half of the soccer match are then omitted. Half time is indicated by a half time icon  66 , and half time analysis is indicated by an analysis icon  67 . Events making up the majority of the second half are denoted by ellipsis, and a final goal icon  68  denotes the end of the match. It can be seen that in the embodiment of  FIG. 8 , each icon is presented together with an interest level indicator, denoted by a number of stars below each icon, ranging from one to five. 
     As described above, the stream of icons of  FIG. 8  can be downloaded from the video server to a user&#39;s device in advance of the video data itself. A user can then select one or more icons in order to obtain the video content associated with the selected icons. 
     When the stream of icons partially illustrated in  FIG. 8  is displayed to the user, the user may additionally be provided with a viewing duration indicative of the time taken to display the video data represented by all icons. This can be achieved by incorporating with data for each icon a time parameter indicating the viewing duration of the video data represented by that icon. Thus, in the example of  FIG. 8 , the time for the entire soccer match, together with half time, may be of the order of  110  minutes, and this time may be displayed to the user. It may be however, that a user does not wish to expend that length of time watching an entire soccer match. Therefore, using the icon data downloaded to the user&#39;s device, it is possible to specify preferred content, and condense the video data in accordance with the preferred content. 
     For example, a user may input data indicating that he/she wishes only to view video data which is classified as having an interest level in excess of three stars. On making this selection, a user is then presented with a subset of the icons as illustrated in  FIG. 9 . Specifically, only the defensive action icon  61 , the offside icon  62 , the goal icon  65 , and the final goal icon  68  are displayed to a user. Again, the user is presented with an indication of the time taken to view all video data associated with these icons. If it is determined that the time indicated to view the video data associated with these icons is acceptable to a user, the user can then request the appropriate video data from the video server and proceed to watch the video data. 
     The embodiment of the present invention as described above allows a user to download icons which provide an indication of the viewing duration of the associated video data, and then to make a further specification so as to obtain a subset of icons representing a subset of video data and an indication of the (shorter) time that would be required to watch the video data represented by the subset of icons. It will be appreciated, that this embodiment of the invention need not necessarily be used in connection with a subjective value assessment as described above, but instead the sequence of icons illustrated in  FIG. 8  could be displayed to a user, the display time would then be determined to be unacceptable, and a user could then specify that only goal events for example, were desired. A subset of sequence of icons representing all goal events, would then be displayed to the user together with the associated viewing duration, and the user could then proceed to watch only the goal video data in the manner described above. Alternatively, the user may specify that it is desired to view only the actual match, not pre-match and half-time discussions and interviews, and the video data could then be condensed to remove, for example, the half-time and analysis programme elements respectively represented by the icons  66 ,  67  in  FIG. 8 . 
     The condensing process described above, is not restricted to applications in which icons are delivered in advance and then used to enable download of video data. For example, as illustrated in  FIG. 10 , a user may review icons and watch video data concurrently.  FIG. 10  illustrates a display screen  69  having a first area  70  in which video data is displayed and a second area  71  in which the stream of icons illustrated in  FIG. 8  is displayed. The duration of the video data is indicated in an area  72  of the display screen. Video data is displayed in the area  70 , and the icon representative of the data currently being displayed is highlighted in the area  71 . In the illustration of  FIG. 10 , the icon  60  is highlighted. The user may skip backwards and forward within the video data by selecting appropriate icons in the area  71 . However, if a user is running short of time and wishes to watch only the highlights of the game, an appropriate selection can be made from, for example, a menu so as to reduce the sequence of icons in the area  71  to, for example, that illustrated in  FIG. 9 , in the manner described above. 
     The ability of the invention to condense video data is not restricted to video data represented using icons. For example, a user may be presented with a textual identifier identifying video data together with an estimated viewing duration for the video data. The user can then input data indicative of a wish to condense the video data, this data additionally specifying preferred programme content. In some embodiments the condensed data is then presented directly to the user, whilst in other embodiments, the condensed data is represented to the user by a further identifier, allowing a user to further condense the data prior to viewing. 
     In an alternative embodiment of the present invention, a user establishes a profile indicative of programme content of interest. The profile may specify a plurality of classes of data in which a user is interested, together indications of interest in each specified class. This user profile can then be used to condense video data as described above. For example, a user may be presented with an identifier or icon sequence representing video data, and then request that the video data is condensed based upon the established profile by, for example, including only classes included within the profile having an interest level above a predetermined threshold. 
     In some embodiments of the present invention, a user presents details of a desired viewing duration. The video data is then condensed to provide video data having a duration as close as possible to the desired viewing duration. In such embodiments of the invention, a user profile can be used in the manner described above, or alternatively a user can input data indicating how condensing should be carried out. 
     Although preferred embodiments have been described above, it will be appreciated that various modifications can be made without departing from the spirit and scope of the invention defined by the appended claims.