Abstract:
A method of forming a picture in picture (PIP) service over an internet protocol (IP) transmission to one or more users, the method comprising the steps of: receiving a request for a PIP channel comprising a first predetermined channel superimposed with a second predetermined channel; determining if the PIP channel already exists; forming the PIP channel if it does not already exist; and transmitting the PIP channel on a dedicated channel to any users who have requested that PIP channel.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a method and apparatus for providing a picture in picture service to a user, and to a system and a computer program product for providing a picture in picture service. 
       BACKGROUND OF THE INVENTION 
       [0002]    In the Internet Protocol Television (IPTV) environment where a plurality of multicast transmissions are transmitted to a user, there exist several service providers which provide a picture in picture (PIP) service. PIP services are those in which two or more video streams are displayed simultaneously. Generally one is smaller than the other (or others) and the smaller one overlays the larger. 
         [0003]    In these current services the PIP is provided in an analogue format and the set top box (STB) or television (TV) at the user end of the transmission is where the PIP is formed. 
         [0004]    In the digital format and with services such as internet protocol TV (IPTV) each picture requires a tuner and sufficient bandwidth for each. For example to have a PIP based on three channels, three tuners or decoders would be required at the STB or TV and a bandwidth of &gt;10 Mb/s (3×3.75 Mb/s). This is costly in terms of equipment and bandwidth costs and overheads. Accordingly this functionality is rarely made available to users. 
         [0005]    One object of the present invention is to provide a PIP method and apparatus which overcomes at least one of the problems of the prior art. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention is directed to the method and system as defined in the independent claims. 
         [0007]    According to a first aspect of the present invention, there is provided a method of forming a picture in picture (PIP) service over an internet protocol (IP) transmission to one or more users, the method comprising the steps of: receiving a request for a PIP channel comprising a first predetermined channel superimposed with a second predetermined channel; determining if the PIP channel already exists; forming the PIP channel if it does not already exist; and transmitting the PIP channel on a dedicated channel to any users who have requested that PIP channel. 
         [0008]    According to a second aspect of the present invention, there is provided a system of forming a picture in picture (PIP) service over an internet protocol (IP) transmission to one or more users, the system comprising: means for receiving a request for a PIP channel comprising a first predetermined channel superimposed with a second predetermined channel; means for determining if the PIP channel already exists; means for forming the PIP channel if it does not already exist; and means for transmitting the PIP channel on a dedicated channel to any users who have requested that PIP channel. 
         [0009]    According to a third aspect of the present invention, there is provided a computer program product stored on a computer readable medium for forming a picture in picture (PIP) service over an internet protocol (IP) transmission, the computer readable medium comprising program code for performing the steps of: receiving a request for a PIP channel comprising a first predetermined channel superimposed with a second predetermined channel; determining if the PIP channel already exists; forming the PIP channel if it does not already exist; and transmitting the PIP channel on a dedicated channel to any users who have requested that PIP channel. 
         [0010]    Further embodiments of the invention are provided in the appended dependent claims. 
         [0011]    The result of preparing the PIP channel in this way is that the STB or TV at the user end only needs one tuner. As the PIP is created, encoded as a single channel and sent as a signal channel there is no need for the STB or TV to have additional tuners at the user location. Apart from the PIP client, all other resources for this invention will be found at the headend equipment and will be used for multiple users, thereby minimizing the overhead in equipment for the system as a whole. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Reference will now be made by way example, to the accompanying drawing, in which: 
           [0013]      FIG. 1  is an example of a picture in picture (PIP); 
           [0014]      FIG. 2  is a block diagram of a system for delivering a PIP service to a user, according to the present invention; 
           [0015]      FIG. 3  is a block diagram for explaining the functionality of the PIP service, according to the present invention; 
           [0016]      FIG. 4  is a table for showing the PIP table of information; and 
           [0017]      FIG. 5  is a flow chart of the steps carried out in the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]      FIG. 1  shows a picture in picture service which has been generated, for example as part of an IPTV service providing a plurality of multicast transmissions to a plurality of users. The picture in picture service shows a main picture  100  and a picture in picture (PIP)  102 . This shows the nature of PIP, but clearly many variations are possible (e.g., more PIP&#39;s, different sizes, formats, etc.). 
         [0019]      FIG. 2  is a block diagram of a system  200  for providing a PIP to a user location  202 . The user location  202  includes a residential gateway  204  connected to, for example, a personal computer (PC)  206 , a telephone (either internet protocol or normal telephony)  208 , a STB  210  and TV  212 . The gateway receives information from the Network  214 . The information may be in the form of multicast transmission  216  from a headend equipment  218  or other type of transmission  220  from so called middleware equipment  222 . The multicast transmission  216  may be in the form of TV transmission to multiple users all subscribing to the same multicast channels. This may be carried out by any appropriate headend equipment  218  including encoders, transcoders, etc. The multicast streaming  216  uses the Internet Group Management Protocol (IGMP). 
         [0020]    A unicast may also be a TV unicast which offers a different stream to each user. The video on demand (VOD) real time streaming protocol (RTSP) is used for the unicast. This unicast can be produced by the middleware equipment  222 , which can take on any appropriate type. Using a unicast a user may also obtain Time Shift TV or Network Personal Video Recorder (NPVR) services through a portal. This allows time user to have pause, fast-forward and remind functions on a unicast made broadcast. 
         [0021]    The middleware  222  may also include a soft switch  224  which may provide a telephony service, such as Voice Over Internet Protocol (VOIP) from Public Switch Telephone Network (PSTN)  225 . 
         [0022]    The system  200  also includes server  226  at the headend which is a Picture in Picture protocol (PIPP) server  226  and a PIPP client  228  at the user end. The detailed operation of this server  226  and client will be described in great detail below. 
         [0023]    The PIPP server  226  may form part of the encoders or part of the control equipment or software. The PIPP client  228  is most likely to be located in the STB  210  or TV receiver  212  as appropriate. 
         [0024]      FIG. 3  outlines how the new protocol PIPP will allow a user to enquire about the availability of IGMP allowing a PIP request on a particular channel, and, how the network encoder can build an appropriate PIP multicast channel. 
         [0025]    The user is viewing a multicast of a specific channel (this will be referred to herein as “channel A”) using a STB  300  which includes a connection with a PIPP client  302 . The client may be located on a PC  304  or perhaps within the gateway or as part of the STB or TV. The user wishes to view a further channel (this will be referred to as “channel B”) as a PIP within channel A. The user makes a request  306  via the PIP client  302  and the network  308 . The request  306  is received at the PIPP server  310  and entered into the PIPP server table  312 . The table  312  details are shown in  FIG. 4  and will be described in more detail below. The server table  312  makes a request for formation of the required channel to the PIP encoder  314 . The encoder  314  monitors the network  308  to identify the existing channels which are currently being transmitted on the network  308 . The encoder  314  can then re-encode the required combination of channels to build the necessary PIP channel. A video recorder and player  316  may be used to store the PIP channel prior to transmitting to the user. The table  312  is updated with each change, amendment, variation, etc. to the PIP channels. 
         [0026]    An enquiry is then made to the IGMP protocol to determine if there is already a PIP channel containing channel A with a PIP of channel B. If such a PIP channel exists, the PIP table  312  is updated with the details of the IGMP port carrying the required PIP channel and the user is notified of the same so that they can turn the turner of the STB  300  or TV to this channel. If the IGMP enquiry determines that no relevant PIP channel exists a determination is made as to whether the available bandwidth, either to the user or in total, to support the creation of a new PIP channel. If there are sufficient resources for creation of a new channel a new PIP channel will be created by the PIP encoder  314  and the PIP table  312  will be updated. The updated PIP table  312  will then be communicated to the PIPP client  302  via the PIPP server  310 . The user may then connect to the newly created PIP channel. 
         [0027]    If there is not sufficient bandwidth available to create a new PIP channel at the present time, a request may be entered in the IGMP server for notification of when sufficient bandwidth is available. When notification is received a determination is made as to whether or not the new channel is still required and if so it is formed and the PIP table  312  is updated. 
         [0028]    The PIPP server table  312  is used to ensure that details of available PIP channels are communicated with the PIP client  302  at the user end. If the request  306  for a particular PIP channel indicates that the particular PIP channel already exists the STB  300  or TV may be returned directly without need for the request to go to the PIPP server  310 . 
         [0029]    Referring now to  FIG. 4 , an example of PIP table  400  information is shown. The table  400  sets out details of the main channel (e.g., channel A)  402 , the sub channel (e.g., channel B)  404  and the IGMP port  406  on which the PIP channel may be transmitted. 
         [0030]    The result of preparing the PIP channel in this way is that the STB or TV at the user end only needs one tuner. As the PIP is created, encoded as a single channel and sent as a signal channel there is no need for the STB or TV to have additional tuners at the user location. Apart from the PIPP client all other resources for this invention will be found at the headend equipment and will be used for multiple users, thereby minimizing the overheads in equipment for the system as a whole. 
         [0031]    Referring now to  FIG. 5 , the main steps of the present invention are set out. 
         [0032]    The user enters a request for a PIP service comprising channel A and channel B ( 500 ) to the PIPP client. The request is transmitted to the PIPP server and received there  502 . A request for the required PIP server is made via the PIP table and the IGMP. A determination is made to determine if the service already exists ( 506 ). 
         [0033]    If yes,  508  the user is connected to the service by connecting to the correct channel as notified to the PIPP server by IGMP server ( 510 ). 
         [0034]    If the service does not already exist (no,  512 ) a determination is made as to whether there is available bandwidth ( 514 ). If there is not sufficient bandwidth (no,  516 ) a request for this service is queued to await available bandwidth  518 . The check for available bandwidth (determination at step  514 ) continues until there is available bandwidth (yes,  520 ) or until the user request is cancelled ( 522 ). At that point the process stops  524  and all entries in the PIPP client and server relating to required PIP channel are deleted as will be described in greater detail below ( 530 ,  532 ,  534 ,  524 ). 
         [0035]    If there is sufficient bandwidth to form a PIP channel (yes,  520 ) a new PIP channel is formed in any appropriate way, for example using encoder, recorded material, etc. to produce the required channel  526 . Once the channel is formed the PIP table is updated at both the PIPP server and client. By updating the PIPP server, other users requesting the same combination of channels in PIP can be notified of the same by the PIPP server without another channel that is the same being created ( 526 ). The user (or users) can then be connected to the PIPP channel  528 . 
         [0036]    Once all users connected to a given PIP channel have disconnected from the channel, by turning to a different channel, for example, ( 530 ) the PIPP server and client are updated to terminate the service ( 532 ). The PIP table is cleared of all details of the PIP channel and if appropriate the IGMP server is notified ( 534 ). The process then stops ( 524 ). 
         [0037]    While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood that various changes in form and detail may be made therein without departing from the spirit, and scope of the invention.