Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
  • H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
  • H04N21/44—Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs
  • H04N21/4408—Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs involving video stream encryption, e.g. re-encrypting a decrypted video stream for redistribution in a home network
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N5/00—Details of television systems
  • H04N5/76—Television signal recording
  • H04N5/91—Television signal processing therefor
  • H04N5/913—Television signal processing therefor for scrambling ; for copy protection
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N7/00—Television systems
  • H04N7/16—Analogue secrecy systems; Analogue subscription systems
  • H04N7/167—Systems rendering the television signal unintelligible and subsequently intelligible
  • H04N7/1675—Providing digital key or authorisation information for generation or regeneration of the scrambling sequence
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N5/00—Details of television systems
  • H04N5/76—Television signal recording
  • H04N5/91—Television signal processing therefor
  • H04N5/913—Television signal processing therefor for scrambling ; for copy protection
  • H04N2005/91307—Television signal processing therefor for scrambling ; for copy protection by adding a copy protection signal to the video signal
  • H04N2005/91321—Television signal processing therefor for scrambling ; for copy protection by adding a copy protection signal to the video signal the copy protection signal being a copy protection control signal, e.g. a record inhibit signal

Definitions

• the invention relates to a video signal receiving device to which a video signal recording device can be connected.
• US Pat. No. 4,930,160 describes a video signal receiving device in which the display of a video broadcast can be blocked by a control device. For this purpose, a code generated and transmitted by the transmitter is evaluated in the control device. Basically, in the interests of the transmitters, there is a tendency on the part of the receiving device manufacturers to make it more difficult or even impossible to record programs which are subject to access protection.
• the synchronizing signal component of the video signal is influenced in the receiving device in such a way that display on a screen device is readily possible, but recording with a video recorder delivers extremely poor quality or is even impossible.
• the synchronous signal component is provided with a deliberately introduced phase jitter in a color encoder which converts digitally transmitted and received video signals into analog signals for controlling conventional television sets and video recorders. It is possible for the synchronization devices of the television set, which usually have a relatively low time constant, to to follow senjitter and produce a high quality image. Recording devices, however, in particular video recorders, cannot follow the phase jitter of the synchronous signal component due to the inert mass of the rotating video drum.
• the object of the invention is to provide another solution for the prevention of a recording of programs with access protection, which is as simple as possible to implement and can be applied to today's recording devices and video display devices without further disadvantages.
• this object is achieved by a video signal receiving device according to the features of claim 1.
• Another object is to provide a workaround for the recording protection achieved with a video signal receiving device according to the invention.
• the invention is based on the knowledge that video recorders manufactured and sold today, in particular video recorders, can only be supplied with video information using a composite video signal.
• the composite video signal is in most cases the so-called Chromaticity blanking signal (CVBS).
• the CVBS signal contains both horizontal synchronizing pulses, color burst, black and white image information and color image information as well as vertical synchronizing pulses in a single signal.
• recording devices are available which have an input for a composite picture blanking synchronous signal (BAS or Y) with the black-and-white picture information and the horizontal and vertical pulses, and an input for a signal (C) including the color burst, including the color burst exhibit. This applies to almost all video recorders currently available.
• the standardized SCART socket serves as the connecting means for these recording devices to a receiving device.
• television sets can also be supplied with video information via the red-green-blue (RGB) color signals and the separate lines for synchronous and vertical pulses.
• RGB red-green-blue
• the SCART socket is also used for this.
• Video recorders that are controlled with RGB signals are currently not manufactured or sold.
• a first connection socket is provided for connecting the television set and a further connection socket for connecting the video recorder.
• the connection sockets are, for example, SCART sockets. If a program is received for which reception authorization is required, the connection for the video recorder is blocked. The program can only be viewed on the monitor, but not recorded. Because of the different connection interfaces for the television and video recorder in the receiving device, the video recorder cannot be operated on the socket provided for the television. Recording of a program provided with authorization to receive is therefore not readily possible with commercially available video recorders. The video recorder connection is not blocked during reception of a program that is not authorized to receive, so that a program can be recorded.
• the program can also be displayed on the television , whereby the user can also request further functions, for example teletext reception or operating menus shown on the screen.
• the video signal receiving device can be designed as a separate device with externally accessible connections for the video recorder and television set, for example in the form of SCART sockets, or within the housing of a television set, in which case expediently only the connection for the video recorder is accessible. Practical protection against undesired recording is achieved according to the invention with less effort compared to the prior art. The playback quality on the TV is not reduced.
• the information about blocking the connection for the recording device is transmitted on the transmitter side.
• control means are provided in the receiving device which recognize the code fed in by the transmitter for switching off the output for the recording device. If programs are transmitted in encrypted form, the control device detects receipt of the encrypted program and blocks the output for the recording device. If it is desired on the transmitter side that even unencrypted broadcasts should not be recorded, it is sufficient to transmit a corresponding identification signal which the control device recognizes and converts into a shutdown of the output for the recording device.
• the video signal receiving device is simple and can be implemented with existing circuit means without any significant additional effort. Bypassing the recording protection is only possible with an additional circuit measure.
• This circuit measure consists of an additional device which generates a composite video signal from the RGB signals and horizontal / vertical synchronizing signals which can be tapped at the connection for the television signal, either a composite signal or Y and C signals or a combination of both.
• an additional device is currently not available. According to the current state, the video signal receiving device according to the invention therefore offers good recording protection with very little effort.
• the video signal receiving device 1 receives digital video signals fed in at an antenna 2, which are coded according to a digital standard for coding moving pictures, for example MPEG2. Alternatively, a feed can be provided via a cable network.
• the device 1 contains an output connection 3, to which a video recorder 4 is connected, and an output connection 5, to which a television set 6 is connected.
• the signal fed in by means of the antenna 2 is demodulated in a device 7 and converted into a digital data stream.
• the digital data stream is then fed to a device 8 which is used to decrypt data encrypted for the purpose of access control.
• the device 8 can expediently be plugged into the device and can be obtained from the operator of the received transmitter against payment of a license fee.
• the device 8 contains the key for decrypting the encrypted transmitted data.
• the decrypted data stream delivered by the device 8 is fed to a device 9 which carries out the decoding in accordance with the transmission standard.
• the device 9 is an MPEG2 decoder.
• the decoder 9 generates Output signals for the branch for connecting the video recorder and the branch for connecting the television set.
• a digital / analog conversion is carried out in each branch by a respective unit 10 or 11.
• the RGB signals and horizontal and vertical synchronizing signals emitted by the digital / analog converter 11 are fed directly to the output connection 5.
• RGB signals In the branch for connecting the video recorder, the digital / analog converter 10 also generates RGB signals and the corresponding synchronizing pulses which are fed to a device 12. In the device 12, these signals are converted into a single chrominance frame blanking synchronous signal FBAS.
• FBAS chrominance frame blanking synchronous signal
• the implementation takes place according to the generally known PAL / NTSC / SECAM standards.
• the CVBS signal is available at connection 3.
• BAS and C signals can be generated (not shown).
• connections 3 and 5 are expediently designed as standardized SCART sockets. At connection 5, only the connecting lines for the RGB signals and the horizontal and vertical signals are connected, if necessary additionally reference potential connecting lines. At connection 3, the lines for the composite signal or / and the lines for the BAS signal and the C signal are connected.
• a conventional video recorder 4 is connected to the connection 3, to which the video information can only be supplied via a color type blanking synchronizing signal.
• the commercially available video recorder 4 cannot evaluate RGB signals.
• a commercially available television 6 is connected to the connection 5 and can convert at least RGB signals and the corresponding synchronizing signals into an image that can be displayed on the screen.
• the branch for the video recorder can be switched off by control on the transmitter side, so that the received program cannot be recorded via a video recorder 4, but can be viewed on the screen device 6.
• the device 20 recognizes that an encrypted broadcast is being received. This is communicated to the control device 20 by the decryption device 8.
• the device 20 then switches off the branch for connecting the video recorder, for example the corresponding output of the MPEG2 decoder.
• control device 20 contains means by which a control command contained in the video data stream is recognized, so that the branch for connecting the video recorder is then switched off.
• a circumvention of the recording protection described is possible, however, by designing an additional device which can be connected to the connection 5 and converting the RGB signals and synchronizing signals provided there into a color type blanking synchronizing signal or BAS and C signals .
• the video recorder can then evaluate and record the signals present at the unblocked connection 5.
• the practical device would essentially contain a PAL / NTSC / SECAM coder 12.

Landscapes

• Engineering & Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Computer Security & Cryptography (AREA)
• Television Systems (AREA)
• Television Signal Processing For Recording (AREA)
• Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
• Color Television Systems (AREA)
• Synchronizing For Television (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (1)

Family

ID=7766663

Family Applications (1)

Country Status (9)

Families Citing this family (2)

Citations (2)

Family Cites Families (6)

• 1995
  • 1995-07-12 DE DE19525425A patent/DE19525425C1/de not_active Expired - Fee Related
• 1996
  • 1996-04-11 CN CN96195448A patent/CN1097391C/zh not_active Expired - Lifetime
  • 1996-04-11 WO PCT/DE1996/000639 patent/WO1997003519A1/de active IP Right Grant
  • 1996-04-11 KR KR10-1998-0700202A patent/KR100411773B1/ko not_active Expired - Lifetime
  • 1996-04-11 JP JP9505394A patent/JPH11509059A/ja not_active Withdrawn
  • 1996-04-11 ES ES96908025T patent/ES2127630T3/es not_active Expired - Lifetime
  • 1996-04-11 EP EP96908025A patent/EP0838118B1/de not_active Expired - Lifetime
  • 1996-04-11 DE DE59601016T patent/DE59601016D1/de not_active Expired - Lifetime
  • 1996-04-16 IN IN693CA1996 patent/IN188993B/en unknown
  • 1996-07-12 AR ARP960103563A patent/AR002826A1/es unknown

Patent Citations (2)

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