Copy-protection for laptop PC by disabling TV-out while viewing protected video on PC display

• US 6,272,283 B1
• Filed: 04/22/1998
• Issued: 08/07/2001
• Est. Priority Date: 04/22/1998
• Status: Expired due to Term

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Neomagic Corporation
• Inventors: Nguyen, Thu N.
• Primary Examiner(s): Chevalier, Robert
• Application Number:
  US09/064,364
• Time in Patent Office: 1,203 Days
• Field of Search: H04/N.5913, H04/N.576, 380/95, 380/46, 380/94, 380/1, 380/52, 380/4, 380/55, 360/13, 360/15, 725/31, 725/87, 725/102
• US Class Current: 386/259
• CPC Class Codes: H04N 2005/91314 the copy protection signal being a pulse signal inserted in blanking intervals of the video signal, e.g. pseudo-AGC pulses, pseudo-sync pulses
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• CPC Class Codes: H04N 5/85 on discs or drums
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection

Abstract

Copy protection support is added to the display driver in a laptop PC. Laptop PCs without any copy protection facilitate illegal copying of optical disks such as digital-versatile disk (DVD), since some laptop PCs now include a TV encoder (scan-line converter) that converts the computer-generated formats such as SVGA to TV formats such as NTSC and PAL. While VCRs cannot make copies of computer formats such as SVGA, a VCR connected to the laptop PCs TV-encoder output can make an illegal videocassette copy of a DVD title. The portability of laptop PCs makes them particularly attractive to video thieves. Some PCs are being equipped with TV encoders with advanced copy-protection features such as MacroVision encoders. The video BIOS determines if the TV encoder is MacroVision compliant and is queried by the display driver when a DVD navigator or player requests MacroVision encoding. MacroVision-compliant TV encoders add low-level pulses to the TV output that TV sets confuse with sync pulses degraded by VCR copying. Thus the TV output cannot be copied when MacroVision encoding is used. The display driver emulates copy-protection for older TV encoders that are not MacroVision-compliant. The display driver stops play of copy-protected DVD titles until a user disables the TV output. Multiple DVD players are controlled by the display driver by storing a list of DVD identifiers an the DVD identifier of the last DVD navigator or player to enable MacroVision encoding.

Claims

1. A method for emulating copy-protection on a personal computer (PC) with a computer display for displaying in a computer-generated format that cannot be copied by a VCR recorder, the method comprising the steps of:

(a) sending a copy-protection request from a video player application to a display driver;

(b) determining when the PC contains a TV encoder that has advanced copy-protection features that prevent illegal copying;

when the PC contains a TV encoder that does not have advanced copy-protection features;

(c) determining when the TV encoder is active for converting computer-generated graphics for display on the computer display to TV-encoded graphics viewable on a TV monitor;

(d) when the TV encoder is active, displaying a message on the computer display to a user of the PC, the message requesting that the TV encoder be disabled before the video player application resumes play of a copy-protected video;

(e) when the TV encoder is not active, sending a status word to the video player application indicating that the TV encoder is off and the copy-protected video can be safely played to the computer display;

when the PC contains a TV encoder with advanced copy-protection features;

(f) determining when the TV encoder is not active for converting computer-generated graphics to TV-encoded graphics viewable on a TV monitor and signaling the video player application to continue playing the copy-protected video to the computer display;

(g) when the TV encoder is active and the copy-protection request is a request to enable the advanced copy-protection features of the TV encoder, sending an encryption key from the video player application to the TV encoder to enable the advanced copy-protection features; and

(h) when the TV encoder is active and the copy-protection request is a request to disable the advanced copy-protection features of the TV encoder, sending an encryption key from the video player application to the TV encoder to disable the advanced copy-protection features,

whereby the display driver emulates copy protection for the TV encoder without advanced copy-protection features by disabling the TV encoder when a copy-protected video is played, but the display driver sends the encryption key to the TV encoder with advanced copy-protection features.

2. The method of claim 1 wherein the copy-protection request includes a requested operation and a player-app identifier, the player-app identifier uniquely identifying the video player application when a plurality of video player applications request copy protection;

wherein the method further comprises;

comparing the player-app identifier from the copy-protection request to a list in the display driver of player-app identifiers for the plurality of video player applications; and

generating an error when the player-app identifier matches one of the player-app identifiers in the list,

whereby the display driver provides copy protection for multiple video player applications.

3. The method of claim 2 further comprising for step (g) when the TV encoder is active and the copy-protection request is a request to enable the advanced copy-protection features of the TV encoder, writing the player-app identifier to a last identifier register in the display driver.

4. The method of claim 3 further comprising for step (h) when the TV encoder is active and the copy-protection request is a request to disable the advanced copy-protection features of the TV encoder, comparing the last identifier register to the player-app identifier to determine a match when the video player application was a last application to enabled the advanced copy-protection features of the TV encoder;

only sending the encryption key from the video player application to the TV encoder to disable the advanced copy-protection features when a match is detected; and

returning an error code to the video player application when a match is not detected, whereby only a last video player application to enable the advanced copy-protection features may disabled the advanced copy-protection features.

5. The method of claim 4 further comprising for step (e) when the TV encoder is not active, and the TV encoder does not have advanced copy-protection features:

preventing enablement of the TV encoder by a hotkey by writing a block-TV flag in a system registry for the PC, whereby the TV encoder is prevented from being re-enabled by the hotkey when the copy-protected video is played.

6. The method of claim 5 wherein the video player application is a DVD navigator application for playing digital-versatile disk (DVD) titles.

7. The method of claim 2 wherein the advanced copy-protection features include MacroVision-compliant encoding.

8. The method of claim 2 wherein for step (b), a video BIOS for the PC determines when the PC contains the TV encoder with advanced copy-protection features that prevent illegal copying by reading feature registers on the TV encoder during system initialization, the video BIOS storing a compliant flag in a scratch register indicating when the TV encoder has the advanced copy-protection features, wherein the display driver queries the video BIOS to read the compliant flag in the

scratch register to determine determines when the PC contains the TV encoder with advanced copy-protection features;

whereby the feature registers on the TV encoder are read during system initialization.

9. A laptop personal computer (PC) for preventing illegal copying of videos played on the laptop PC, the laptop PC comprising:

a graphics controller for generating a pixel stream in a computer-graphics format, the pixel stream for display by a flat-panel display on the laptop PC;

an optical-disk player for playing copyrighted optical disks, the optical-disk player outputting copy-protected videos to the graphics controller for display;

a TV encoder, coupled to receive the pixel stream from the graphics controller, for converting the computer-graphics format to a TV format;

a video BIOS for controlling the graphics controller, the video BIOS having a scratch register for storing a flag indicating when the TV encoder is compliant with advanced copy-protection standards;

a display driver, coupled to the video BIOS, for further controller the graphics controller, the display driver also for controlling the TV encoder;

a player application for controlling the optical-disk player, the player application including means for generating a request for copy protection to the display driver;

a copy-protection function in the display driver for receiving the request from the player application, the copy-protection function including means for reading the scratch register in the video BIOS to determine when the TV encoder can accept advanced copy-protection commands from the player application;

transmitting means, in the display driver, for transmitting a encryption key from the player application to the TV encoder when TV encoder can accept advanced copy-protection commands from the player application; and

emulation means, in the display driver, for disabling the TV encoder when the request from the player application is a request to enable copy-protection in the TV encoder and the flag in the video BIOS indicates that the TV encoder is not compliant with advanced copy-protection standards,

whereby copy-protection is emulated by the display driver for non-compliant TV encoders by disabling output from the TV encoder in the TV format.

10. The laptop PC of claim 9 further comprising:

a plurality of player applications for playing a plurality of copy-protected videos, each player application having a player identifier;

a last-identifier register, readable by the display driver, for storing the player identifier for a last player application to enable copy protection;

compare means, in the display driver, for comparing the last-identifier register to the player identifier for a player application requesting copy protection;

error means, in the display driver, for generating an error code and not disabling copy-protection by the TV encoder when the compare means does not signal a match,

whereby only a last player application to enable copy protection can disable copy protection.

11. The laptop PC of claim 10 further comprising:

an identifier list, readable by the display driver, for storing player identifiers for all player applications requesting copy protection; and

second compare means, for comparing the player identifier to the identifier list and generating an error code when a match is found,

whereby only player applications with unique player identifiers can re-configure copy protection.

12. The laptop PC of claim 9 further comprising:

a system registry for storing system parameters;

a TV flag in the system registry for indicating when the TV encoder is disabled, the TV flag preventing other applications from re-enabling the TV encoder when disabled by the display driver.

13. The laptop PC of claim 9 wherein the computer-graphics format is non compatible with the TV format, wherein a tape recorder attached to the pixel stream is unable to record a tape for viewing on a standard TV monitor.

14. The laptop PC of claim 9 wherein the TV format is NTSC or PAL.

15. The laptop PC of claim 9 wherein the pixel stream is also for display on an external cathode-ray tube (CRT) monitor attached to the laptop PC.

16. The laptop PC of claim 9 further comprising:

a status code returned to the player application from the display driver, the status code including;

a successful operation flag to indicate when the request for copy protection was successfully completed;

a TV-on flag for indicating when the TV encoder is enabled and converting the computer-graphics format to the TV format;

a compliant flag for flag indicating when the TV encoder is compliant with advanced copy-protection standards.

17. A computer-program product comprising:

a computer-usable medium having computer-readable program code means embodied therein for establishing copy-protection on a personal computer (PC), the computer-readable program code means in the computer-program product comprising;

means for sending a copy-protection request from a video player application to a display driver;

compliant means for determining when the PC contains a TV encoder that has advanced copy-protection features that prevent illegal copying;

TV on means for determining when the TV encoder is active for converting computer-generated graphics for display on a computer display to TV-encoded graphics viewable on a TV monitor;

first legacy means, activated when the PC contains a TV encoder that does not have advanced copy-protection features, for displaying a message on the computer display to a user of the PC, the message requesting that the TV encoder be disabled before the video player application resumes play of a copy-protected video when the TV encoder is active;

second legacy means, activated when the PC contains a TV encoder that does not have advanced copy-protection features, for sending a status word to the video player application indicating that the TV encoder is off and the copy-protected video can be safely played to the computer display, when the TV encoder is not active;

advanced copy-protection means, activated when the PC contains a TV encoder with advanced copy-protection features, including;

advanced TV off means, activated when the TV encoder is not active, for converting computer-generated graphics to TV-encoded graphics viewable on a TV monitor and signaling the video player application to continue playing the copy-protected video to the computer display;

key enable means, activated when the TV encoder is active and the copy-protection request is a request to enable the advanced copy-protection features of the TV encoder, for sending an encryption key from the video player application to the TV encoder to enable the advanced copy-protection features; and

key disable means, activated when the TV encoder is active and the copy-protection request is a request to disable the advanced copy-protection features of the TV encoder, for sending an encryption key from the video player application to the TV encoder to disable the advanced copy-protection features,

whereby the display driver emulates copy protection for the TV encoder without advanced copy-protection features by disabling the TV encoder when a copy-protected video is played, but the display driver sends the encryption key to the TV encoder with advanced copy-protection features.

18. The computer-program product of claim 17 wherein the copy-protection request includes a requested operation and a player-app identifier, the player-app identifier uniquely identifying the video player application when a plurality of video player applications request copy protection;

wherein readable program code means further comprises;

compare means for comparing the player-app identifier from the copy-protection request to a list in the display driver of player-app identifiers for the plurality of video player applications; and

error means for generating an error when the player-app identifier matches one of the player-app identifiers in the list,

whereby the display driver provides copy protection for multiple video player applications.

19. The computer-program product of claim 18 further comprising:

a last identifier register in the display driver;

last writing means, activated when the TV encoder is active and the copy-protection request is a request to enable the advanced copy-protection features of the TV encoder, for writing the player-app identifier to a last identifier register in the display driver.

20. The computer-program product of claim 19 further comprising:

last compare means, activated when the TV encoder is active and the copy-protection request is a request to disable the advanced copy-protection features of the TV encoder, for comparing the last identifier register to the player-app identifier to determine a match when the video player application was a last application to enabled the advanced copy-protection features of the TV encoder;

wherein the encryption key is sent from the video player application to the TV encoder to disable the advanced copy-protection features only when a match is detected; and

return means for returning an error code to the video player application when a match is not detected,

whereby only a last video player application to enable the advanced copy-protection features may disabled the advanced copy-protection features.