Patent Publication Number: US-2004045022-A1

Title: Digital message insertion technique for analog video services

Description:
BACKGROUND OF THE INVENTION  
       [0001] The present invention relates to video delivery services and, more particularly, to message insertion for video delivery services.  
       [0002] Television signals delivered to viewers generally include the television programs themselves and commercial advertisements, which are typically inserted into breaks that occur regularly during broadcasts of the television programs. The commercial advertisements are typically created and stored separately from the programs. Then, at appropriate times during a broadcast, the commercial advertisements are spliced into the video feed so as to deliver the advertisements to viewers during program breaks. This provides flexibility for changing the commercial advertisements to be played during a program. For example, various different advertisements directed to local audiences may be inserted into a program that is broadcast over a much wider geographical area. As another example, different advertisements may be used during a rebroadcast of a program than when the program was originally broadcast. Thus, an important aspect of television delivery is program splicing and, more particularly, ad insertion.  
       [0003] Traditionally, cable television delivery systems have processed video signals and delivered them to viewers in analog form. For example, magnetic tape-based systems have been used to perform program splicing for ad insertion. Then, cable plants distribute the spliced television signals to viewers in analog form. For example, fibre ring networks have been used to communicate analog television signals from a master headend to local headends. As a result, there currently exists a vast installed base of cable television equipment that is designed to process and transmit television programming as analog signals. More recently, schemes have become available for performing ad insertion and delivery of video programming to viewers using digital video signals. To implement these schemes, there is a need to replace existing analog equipment with equipment capable of processing and distributing television signals in digital form. However, a major impediment to the adoption of digital cable television networks is the cost associated with replacement of analog equipment with digital equipment.  
       [0004] Therefore, what is needed is technique for reducing the need to replace analog video equipment, while obtaining advantages of digital video signal processing and delivery schemes. It is toward these ends that the present invention is directed.  
       SUMMARY OF THE INVENTION  
       [0005] The invention is a digital program insertion technique for analog video services. In one aspect, a method and apparatus are provided for message insertion and delivery of video signals. A digital video program signal is received (e.g., from a satellite). A digital video message signal is inserted into the digital video program signal in response to an insertion cueing message. The inserting is performed while the digital video program and message signals remain in digital format, thereby forming a combined digital video signal. The combined digital video is then converted to an analog video signal. The analog video signal is distributed to a plurality of viewers using analog distribution equipment.  
       [0006] In another aspect, the digital video signal channels may be distributed to a plurality of local headends via a fibre ring network. The digital video message may then be inserted into the digital video signal at one of the local headends.  
       [0007] The invention provides for the continued use of existing legacy equipment that distributes video signals in analog format. The combined digital video signals may also be delivered in digital format using equipment designed for digital video delivery. Accordingly, the present invention provides for use of newer equipment that processes distributes video signals in digital format while retaining legacy equipment that distributes the video signals in analog format. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0008]FIG. 1 illustrates a block schematic diagram of a video signal insertion and delivery system in accordance with the present invention; and  
     [0009]FIG. 2 illustrates a block schematic diagram of an alternate video signal insertion and delivery system in accordance with the present invention.  
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT  
     [0010] The present invention provides a technique for digital program insertion for analog video services. In accordance with the present invention, video signals are spliced in digital format. Thus, the invention takes advantage of digital techniques for performing ad insertion. For example, audio level matching may be performed using audio metadata (e.g., Dolby Digital metadata). Once combined (i.e. by splicing), the digital video signals are converted to analog format and then distributed to viewers in analog format. Thus, the invention provides for the continued use of existing legacy equipment that distributes video signals in analog format. The combined digital video signals may also be delivered in digital format using equipment designed for digital video delivery. Accordingly, the present invention provides for use of newer equipment that processes and distributes video signals in digital format while retaining legacy equipment that distributes the video signals in analog format. Because legacy equipment can continue to be used, the invention allows video service providers to add digital insertion and distribution equipment to their existing analog networks. Accordingly, the distribution equipment can be gradually changed or added, as desired, to perform digital video signal processing, thereby spreading out the cost of doing so over time.  
     [0011] While the discussion herein is primarily directed to processing and distribution of video signals for a cable television system, it will be apparent that the present invention may be used in other video signal processing and/or communication systems. In addition, while program splicing is discussed in the context of inserting commercial advertisements, it will be apparent that program splicing in accordance with the invention can be employed for other purposes, such as for program editing or for distribution of public announcements or other messages. Also, it will be apparent that associated audio signals generally accompany the video signals as they are processed and distributed, using techniques appropriate for the audio signals.  
     [0012]FIG. 1 illustrates a block schematic diagram of a video signal insertion and delivery system  100  in accordance with the present invention. Video signals are received into a receiver  102 . Generally, these video signals are in a multiplex that includes multiple program channels encrypted and modulated onto a carrier signal that is received from a satellite system. For example, the video signals may be modulated in accordance with quadrature phase shift keying (QPSK) techniques. Each program channel received by the receiver  102  will generally include cueing information that indicates the locations of program breaks for inserting commercial advertisements or other messages.  
     [0013] The receiver  102  typically demodulates and decrypts the program channel signals. Thus, the receiver  102  may be referred to as a multi-decrypting receiver. The receiver  102  may then convert the signals to compressed Moving Picture Experts Group (e.g., MPEG-2) streams along with audio in Dolby Digital AC-3 format. Specifically, the video signals formed by the receiver  102  may be, for example, an unencrypted multiplex of the video channels in the accordance with Digital Video Broadcast-Asynchronous Serial Interface (DVB-ASI) or Motorola Digital Headend Electronic Interface (DHEI) standards.  
     [0014] A splicer  104  receives the video signals from the receiver  102 . The splicer  104  retrieves cueing information from each program channel and, in response, forms cueing messages. In one aspect, the cueing messages are in accordance with standards promulgated by the Society of Cable Telecommunication Engineers (SCTE), known as Digital Program Insertion (DPI). The cuing messages are communicated to a video message or ad server  106 .  
     [0015] The message server  106  stores a number of prerecorded commercial advertisements or other messages ready for delivery to the splicer  104 . For example, the commercial advertisements may be in the form of compressed MPEG-2. In response to the cueing messages, the message server  106  provides selected commercial advertisements to the splicer  104  at appropriate times. The splicing is generally performed during the broadcast (i.e. while the program is being viewed by subscribers), though in some circumstances, it may be desired to perform the splicing in advance.  
     [0016] The splicer  104  then inserts the commercial advertisements into breaks in each of the programs so as to form a combined signal for each channel. Where the splicer  104  receives a multiplex of the channels, the splicer  104  may separate the multiplex into the individual channels prior to splicing video messages from the message server  106  into the individual channels. Then, the splicer  104  may perform statistical multiplexing on the combined signals (i.e. the spliced signals) to regenerate a multiplex of the channels.  
     [0017] The output of the splicer  104  is then delivered to one or more analog playback decoders  108 . While two such decoders are shown, it will be apparent that more of fewer analog decoders  108  may be provided, depending on the circumstances. For example, each decoder  108  may handle a limited number of channels (e.g., six) and, thus, additional decoders  108  may be required depending upon the number of channels to be distributed. The receiver  102 , splicer  104 , message server  106 , and analog playback decoders  108  may be located at the headend  110  of a cable operator.  
     [0018] The analog playback decoders  108  convert the digital video signals received from the splicer  104  to analog format. The analog signals may then be modulated onto a carrier signal for distribution to subscribers  114  via one or more cable plants  112 . Because the video signals from the analog playback decoders  108  are in analog form, the cable plant(s)  112  and subscribers  114  need not have specialized digital equipment for processing the signals. Rather, the cable plant(s)  112  may include legacy analog equipment, while the subscribers  114  may receive the signals using conventional television sets without special equipment, such as a set top box (STB).  
     [0019] In addition, the multiplex may be delivered to one or more digital signal modulators  116 , which may also be located at the headend  110 . The modulators  116  modulate the video signals onto a carrier signal for distribution to subscribers  120 , via one or more cable plant(s)  118 . More particularly, an up-converted and modulated signal from the modulator  116  may be forwarded to the cable plant(s)  118  and then to subscribers  120 . For modulating the digital video signals onto a carrier for distribution, quadrature amplitude modulation (QAM) techniques may be employed at the modulators  116 . Because the video signals from the modulator  116  are communicated in digital form, the cable plant(s)  118  and subscribers  120  will need to have appropriate equipment for processing the digital signals. For example, each subscriber  120  may be required to have a digital set top box (STB).  
     [0020] Though one digital modulator  116  is shown, it will be apparent that more modulators  116  may be utilized depending on the circumstances, such as the number of channels to be distributed. Alternately, where video distribution is performed entirely by analog equipment (e.g., analog cable plants  112 ), the digital signal modulators  116  and associated digital distribution equipment (e.g., digital plants  118 ) may be omitted from the system  100 .  
     [0021]FIG. 2 illustrates a block schematic diagram of an alternate video signal insertion and delivery system  200  in accordance with the present invention. FIG. 2 differs from FIG. 1 principally in that the functions of the headend  110  of FIG. 1 are divided among a master headend  202  and local headends  204 . In addition, a network, such as a fibre ring network  206 , provides for communication among the master headend  202  and local headends  204 .  
     [0022] The master headend includes the receiver  102 . Digital video signals from the receiver  102  are forwarded to the fibre ring network  206  and distributed in digital format via the fibre ring  206  to the local headends  204 . In this manner, the bandwidth requirements for the fibre ring  206  are reduced significantly in comparison to conventional systems in which a fibre ring may be used to distribute analog video signals. Each local headend  204  may include a splicer  104  and a message server  106  for performing program splicing in digital format. Once the splicing is completed, the combined signals in digital format may be forwarded to one or more analog playback decoders  108  where they are converted to analog format for distribution to subscribers via cable plants  112 .  
     [0023] Thus, in accordance with the embodiment of FIG. 2, an existing fibre ring network  206  may be used to communicate digital video signals to subscribers. In addition, the cable plant(s)  112  and subscribers  114  need not have specialized digital equipment for processing the signals. Rather, the cable plant(s)  112  may include legacy analog equipment, while the subscribers  114  may receive the signals using conventional television sets without special equipment, such as a set top box (STB).  
     [0024] In addition, the digital video signals from the fibre ring  206  may be delivered to one or more digital signal modulators  116 , which may also be located at the local headends  204 . The modulators  116  modulate the video signals onto a carrier signal for distribution to subscribers via one or more digital cable plant(s)  118 . Because the video signals from the modulator  116  are communicated in digital form, the cable plant(s)  118  and subscribers  120  will need to have appropriate equipment for processing the digital signals (e.g., a set top box).  
     [0025] In an alternate embodiment of the system  200  of FIG. 2, a splicer  104  and message server  106  may be located in the master headend  202 . In this case, once the splicing is performed, the combined signals may then be distributed in digital format via the fibre ring  206  to the local headends  204 . At the local headends  204 , the digital video signals are converted to analog video signals by analog decoders  108  for distribution in analog format. In addition, at the local headends  204 , the digital video signals may be distributed in digital format by modulators  116  and cable plants  118 .  
     [0026] Thus, techniques have been described for reducing the need to replace analog video equipment, while obtaining advantages of digital video signal processing and delivery schemes.  
     [0027] While the foregoing has been with reference to particular embodiments of the invention, it will be appreciated by those skilled in the art that changes in these embodiments may be made without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims.