Abstract:
A method and a system for transmitting and receiving multimedia content includes identifying the Intra coded frames (I-frames) from a combination of the I-frames, predicted frames (P-frames), and bi-directional predicted frames (B-frames). The method comprises scrambling Intra coded frames selectively, generating multimedia content comprising scrambled information of the I-frames, and transmitting the multimedia content. The method further comprises receiving the multimedia content and &amp;scrambling the I-frames selectively. The system comprises transmitting unit including a selective scrambler, and a processor including an encoding unit and a decoding unit. The system further comprises a receiving unit including selective a descrambler.

Description:
PRIORITY 
       [0001]    This application claims priority under 35 U.S.C. §119(a) to Indian Federation Patent Application Serial No. 2896/CHE/2008 filed in the Indian Intellectual Property Office on Nov. 21, 2008, and to Korean Patent Application Serial No. 10-2009-0049343 filed in the Korean Intellectual Property Office on Jun. 4, 2009, the contents of each of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to the field of rendering multimedia, and more particularly, to a method and a system for transmitting and receiving multimedia content. 
         [0004]    2. Description of the Related Art 
         [0005]    In Direct to Home (DTH), Digital Video Broadcasting-Terrestrial (DVB-T) and Digital Video Broadcasting-Handheld (DVB-H) technologies, multimedia content to be rendered includes frames such as Intra coded frames (I-frames), Predicted frames (P-frames) and Bi-directional frames (B-frames). The multiple frames of the multimedia content are scrambled and transmitted to ensure data security in the multimedia content. 
         [0006]    The scrambled multimedia data may be played or viewed by a user. The video and the image of the scrambled multimedia data may not be displayed to a malicious user. However, high power consumption is required to scramble all frames of the multimedia content. 
         [0007]    In light of the foregoing, there is a need for an efficient technique for securely transmitting and receiving the multimedia content. 
       SUMMARY OF THE INVENTION 
       [0008]    Embodiments of the present invention described herein provide a method and a system for securely transmitting and receiving multimedia content. 
         [0009]    According to the present invention, a method for transmitting multimedia content includes identifying I-frames from a combination of I-frames, P-frames, and B-frames, generating the multimedia content including scrambled information of the I-frames, transmitting the multimedia content, and receiving the multimedia content and descrambling the I-frames selectively. 
         [0010]    According to the present invention, a system for transmitting multimedia content includes a transmitting unit having a selective scrambler for scrambling Mira coded frames selectively, a receiving unit having a descrambling unit for descrambling, the Intra coded frames selectively, and a processor having an encoding unit for encoding key information and a decoding unit for decoding the key information. 
         [0011]    According to the present invention, since the scrambling and descrambling steps are performed only for I-frames, all bytes of video data do not need to be scrambled, thereby reducing power consumption in a transceiver. 
         [0012]    A content provider imposes fees for descrambling I-frames on a mobile TeleVision (TV) user. When only P-frames or P- and B-frames are decoded and reproduced without paying fees, the only viewable images are low-quality ghost images having objects expressed in several rectangular shapes on a screen, making it difficult to identify their original appearances. Since the mobile TV user viewing the ghost images can view complete images by paying fees for descrambling the I-frames, the advertising business is promoted and the inconvenience to the mobile TV user of identifying undesired content immediately after a fee payment is eliminated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The above and other aspects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which: 
           [0014]      FIG. 1  illustrates a network environment, in accordance with which the embodiments of the present invention can be implemented; 
           [0015]      FIG. 2  illustrates an electronic device for receiving multimedia content according to the present invention; 
           [0016]      FIG. 3  illustrates a content server for transmitting the multimedia content according to the present invention; 
           [0017]      FIG. 4  illustrates a method for transmitting a scrambled multimedia content according to the present invention; and 
           [0018]      FIG. 5  illustrates a method for descrambling and displaying a scrambled multimedia content according to the present invention. 
       
    
    
       [0019]    Persons skilled in the art will appreciate that elements in the Figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the Figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0020]    The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following description, a detailed description of known functions and configurations incorporated herein has been omitted for clarity and conciseness. 
         [0021]    Embodiments of the present invention provide a method and a system for scrambling and descrambling I-frames of a multimedia content. Since only the I-frames are scrambled and &amp;scrambled to transmit/receive the multimedia content, power consumption for scrambling and descrambling P- or B-frames is reduced. 
         [0022]      FIG. 1  illustrates a network environment  100 , in accordance with which various embodiments of the present invention are implemented. The environment  100  includes a plurality of electronic devices  105   a  to  105   n.  Examples of the electronic devices  105   a  to  105   n  include, but are not limited to a computer, a laptop, a palmtop, a mobile terminal, and a Personal Digital Assistant (PDA). The electronic device  105   a  is in communication with a content server  115 , through a network  110 . Examples of the content server  115  include, but are not limited to the Digital Video Broadcasting-Terrestrial (DVB-T) content server, Digital Video Broadcasting-Handheld (DVB-H) content server and Direct To Home (DTH) content server. The multimedia content may be telecasted through an Internet channel. The network  110  includes, but is not limited to air-interface and wire-interface. 
         [0023]    The content server  115  includes one or more elements for ascertaining the identity of the visitors and providing the personalized notifications specific to the visitors. The electronic devices  105   a  to  105   n  receive scrambled multimedia data from a content server  115  and descramble the multimedia data. 
         [0024]      FIG. 2  illustrates the electronic device  105   a,  in accordance with the present invention. The electronic device  105   a  includes a bus  205  or other communication mechanism for communicating information, and a processor  210  coupled with the bus  205 . The processor  210  can include an integrated electronic circuit for processing and controlling functionalities of the electronic device  105   a.  The electronic device  105   a  also includes a memory  215 , such as a Random Access Memory (RAM) or other dynamic storage device, coupled to the bus  205  for storing information that can be used by the processor  210 . The memory  215  can be used for storing any temporary information. The electronic device  105   a  further includes a Read Only Memory (ROM)  220  or other static storage device coupled to the bus  205  for storing static information for the processor  210 . A storage unit  225 , such as a magnetic disk or optical disk, is provided and coupled to the bus  205  for storing information. 
         [0025]    The electronic device  105   a  can be coupled via the bus  205  to a display  230 , such as a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD) or a Light Emitting Diode (LED) display, for displaying information. An input device  235 , including alphanumeric and other keys, is coupled to the bus  205  for communicating an input to the processor  210 . The input device can be included in the electronic device  105   a.  Another type of user input device is a cursor control  240 , such as a mouse, a trackball, or cursor direction keys for communicating the input to the processor  210  and for controlling cursor movement on the display  230 . The input device  235  can also be included in the display  230 , such as in the form of a touch screen. 
         [0026]    Various embodiments are related to the use of the electronic device  105   a  for implementing the techniques described herein. In one embodiment, the techniques are performed by the processor  210  using information included in the memory  215 . The information can be read into the memory  215  from another machine-readable medium, such as the storage unit  225 . 
         [0027]    The term “machine-readable medium” as used herein refers to any medium that participates in providing data that causes a machine to operate in a specific fashion. In an embodiment implemented using the electronic device  105   a,  various machine-readable medium are involved, for example, in providing information to the processor  210 . The machine-readable medium can be a storage media, including both non-volatile media and volatile media. Non-volatile media includes, for example, optical or magnetic disks, such as the storage unit  225 . Volatile media includes dynamic memory, such as the memory  215 . All such media must be tangible to enable the information carried by the media to be detected by a physical mechanism that reads the information into a machine. 
         [0028]    Common forms of machine-readable medium include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape or another magnetic medium, a CD-ROM or another optical medium, punchcards, papertape, or another physical medium With patterns of holes, a Random Access Memory (RAM), a Programmable Read Only Memory (PROM), and Electronically Programmable Read Only Memory (EPROM), a FLASH-EPROM, or any other memory chip or cartridge. 
         [0029]    The machine-readable medium can also be a transmission media including coaxial cables, copper wire and fiber optics, including the wires that include the bus  205 . Transmission media can also take the form of acoustic or light waves, such as those generated during radio-wave and infra-red data communications. 
         [0030]    The electronic device  105   a  also includes a communication interface  245  coupled to the bus  205 . The communication interface  245  provides a two-way data communication coupling to the network  110 . For example, the communication interface  245  can be a Local Area Network (LAN) card to provide a data communication connection to a compatible LAN. Wireless links can also be implemented. In any such implementation, communication interface  245  sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information. The communication interface  245  can be a Universal Serial Bus (USB) port. 
         [0031]    The electronic device  105   a  can be connected to the storage device  265  for storing or retrieving information. Examples of the storage device  265  include, but are not limited to, a flash drive, a pen drive, a hard disk or any other storage media. 
         [0032]    The processor  210  may include a decoding unit  250  used for decoding key information of I-frames of the multimedia content. 
         [0033]    The electronic device  105   a  may not include the processing units and the functions of the processing units can be performed by the processor  210 . 
         [0034]    The processor  210  may also be coupled to a receiving unit  255  through the bus  205  or through a communication mechanism for communication information. The receiving unit  255  includes a selective descrambler  260  that descrambles the I-frames of the receiving multimedia content. The selective descrambler  260 , implements one of many &amp;scrambling techniques to descramble the I-frames of the received multimedia content. 
         [0035]      FIG. 3  illustrates a content server  115  in accordance with the present invention. The content server  115  includes a bus  305  or other communication mechanism for communicating information, and a processor  310  coupled with the bus  305 . The processor  310  can include an integrated electronic circuit for processing and controlling functionalities of the content server  115 . The content server  115  also includes a memory  315 , such as a RAM or other dynamic storage device, coupled to the bus  305  for storing information that can be used by the processor  310 . The memory  315  can be used for storing any temporary information. The content server  115  further includes a ROM)  320  or other static storage device coupled to the bus  305  for storing static information for the processor  310 . A storage unit  325 , such as a magnetic disk or optical disk, is provided and coupled to the bus  305  for storing information. 
         [0036]    The content server  115  can be coupled via the bus  305  to a display  330 , such as a CRT, an LCD or an LED display, for displaying information. An input device  335  including alphanumeric and other keys, is coupled to the bus  305  for communicating an input to the processor  310 . The input device can be included in the content server  115 . Another type of user input device is a cursor control  340 , such as a mouse, a trackball, or cursor direction keys for communicating the input to the processor  310  and for controlling cursor movement on the display  330 : The input device  335  can also be included in the display  330 , such as in the form of a touch screen. 
         [0037]    Various embodiments are related to the use of the content server  115  for implementing the techniques described herein. In one embodiment, the techniques are performed by the processor  310  using information included in the memory  315 . The information can be read into the memory  315  from another machine-readable medium, such as the storage unit  325 . 
         [0038]    The term “machine-readable medium” as used herein refers to any medium that participates in providing data that causes a machine to operate in a specific fashion. In an embodiment implemented using the content server  115 , various machine-readable medium are involved, for example, in providing information to the processor  310 . The machine-readable medium can he a storage media including both non-volatile media and volatile media. Non-volatile media includes, for example, optical or magnetic disks, such as the storage unit  325 . Volatile media includes dynamic memory, such as the memory  315 . All such media must be tangible to enable the information carried by the media to be detected by a physical mechanism that reads the information into a machine. 
         [0039]    Common forms of machine-readable medium include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, or another magnetic medium, a CD-ROM or another optical medium, punchcards, papertape, any other physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, or any other memory chip or cartridge. 
         [0040]    The machine-readable medium can also be a transmission media including coaxial cables, copper wire and fiber optics, including the wires that include the bus  305 . Transmission media can also take the form of acoustic or light waves, such as those generated during radio-wave and infra-red data communications. 
         [0041]    The content server  115  also includes a communication interface  345  coupled to the bus  305 . The communication interface  345  provides a two-way data communication coupling to the network  110 . For example, the communication interface  345  can be a LAN card to provide a data communication connection to a compatible LAN. Wireless links can also be implemented. In any such implementation, communication interface  345  sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information. The communication interface  345  can be a USB port. 
         [0042]    In some embodiments, the content server  115  can he connected to the storage device  365  for storing or fetching information. Examples of the storage device  365  include, but are not limited to, a flash drive, a pen drive, a hard disk or any other storage media. 
         [0043]    The processor  310  includes an encoding unit  350  that encodes key information of I-frames of the multimedia content. 
         [0044]    The content server  115  may not include the processing units and the functions of the processing units can be performed by the processor  310 . 
         [0045]    In addition, the processor  310  may be coupled to a transmitting unit  355  through the bus  305  or through a communication mechanism for communication information. The transmitting unit  355  includes a selective scrambler  360  which scrambles the I-frames of the transmitting multimedia content. The selective scrambler  360  implements one of many scrambling techniques to scramble the I-frames of the transmitted multimedia content. 
         [0046]    In another embodiment the content server  115  includes, but is not limited to a DVB-T content server, Digital Multimedia Broadcasting (DMB) content server, Media Forward Link Only (Media FLO) content server, Multimedia Broadcast Multicast Service (MBMS) content server, Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) content server, Digital Video Broadcasting-Handheld (DVB-H) content server and Direct to Home (DTH) content server. The multimedia content may be telecasted through an Internet channel. The content server  115  scrambles the I-frames of the multimedia content and transmits the multimedia content to one or more electronic devices  105   a  to  105   n.    
         [0047]      FIG. 4  illustrates a method for transmitting a scrambled multimedia content, in accordance with the present invention. 
         [0048]    After the method starts at step  405 , a content server generates multimedia content to be transmitted at step  410 . The generated multimedia content is stored in a memory of the content server. Examples of multimedia content include, but are not limited to audio data, image data, and video data in any standard format. 
         [0049]    At step  415 , I-frames in the multimedia content are identified. Further the identifying can be for the one or more frames of the multimedia content, wherein the frames include, but are not limited to P-frames and B-frames. 
         [0050]    At step  420 , a scrambling technique is used to scramble the identified I-frames. A plurality of scrambling techniques may be used to scramble the I-frames of the multimedia content. The scrambling of I-frames may also include scrambling one or more P-frames and B-frames. 
         [0051]    At step  425 , the scrambled multimedia content and the key information of the scrambled I-frames are transmitted, and the method ends at step  430 . 
         [0052]      FIG. 5  illustrates a method for descrambling and displaying a scrambled multimedia content, in accordance with the present invention. 
         [0053]    After the method starts at step  505 , an electronic device receives multimedia content at step  510 . The multimedia content is stored in a memory of the electronic device. 
         [0054]    At step  515 , a check for identifying scrambled frames in the received multimedia content is performed. If at step  515 , the multimedia content includes scrambled frames, then step  520  is performed. If at step  515 , the multimedia content does not include scrambled frames, then step  530  is performed. 
         [0055]    At step  520 , the key information required to descramble is decoded. The key information includes the information to scramble the frames. 
         [0056]    At step  525 , the scrambled frames are descrambled with the key information by a descrambling technique. A plurality of descrambling techniques can be used to descramble the frames of the multimedia content. The descrambling of the frames includes identifying the I-frames after descrambling the frames. 
         [0057]    At step  530 , the multimedia content is displayed on a television, mobile phone, or similar electronic devices. The multimedia content may be telecasted through an Internet channel. The method ends at step  535 . 
         [0058]    According to the present invention, the multimedia content having scrambled I-frames may not be viewed by a malicious user until the electronic device of the user descrambles the I-frames of the multimedia content. The electronic device of the user may descramble the I-frame only by decoding the key information. 
         [0059]    According to the present invention, since the mobile TV user viewing the ghost images can view complete images by paying lees for descrambling the I-frames, the advertising business is promoted and the inconvenience to the mobile TV user of identifying undesired content immediately after a fee payment is eliminated. 
         [0060]    The present invention and its advantages have been described with reference to specific embodiments. However, it will be apparent to a person ordinary skilled in the art that various modifications and changes can be made, without departing from the scope of the present disclosure, as set forth in the claims below. Accordingly, the specification and figures are to be regarded as illustrative examples rather than restrictive examples of the present invention. All such possible modifications are intended to be included within the scope of present invention.