Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1998-04-22
2001-08-07
Chevalier, Robert (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000
Reexamination Certificate
active
06272283
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to personal computer systems, and more particularly to copyright protection for optical disks playing on a portable PC.
BACKGROUND OF THE INVENTION
Portable personal computers (PCs) have rapidly improved in capabilities and many now are as powerful as desktop PCs. Full multimedia capabilities such as high-fidelity audio and full-motion video are increasingly common on moderately-priced notebook and laptop portable PCs. The laptop PCs often include optical disk drives such as a CD-ROM drive.
The next generation of optical disks is known as digital-versatile disk (DVD). The CD-ROM drives on laptop PCs soon will be replaced with DVD drives. DVD has a much higher storage capacity than CD-ROM, enough that an entire motion picture can fit on a single DVD disk. Motion pictures and other copyrighted works are increasingly more expensive to produce, and release of DVD has been delayed to ensure that adequate copy-protection schemes are in place.
A preferred copy-protection scheme was developed by MacroVision Corp. of Sunnyvale, Calif. A number of patents assigned to MacroVision describe in detail such schemes. See for example, U.S. Pat. No. 5,659,613 by Copeland et al., among others. Low-level pulses can be added during the blanking periods that prevent proper sync on poor-quality copies but allow the original, full-signal-strength program to be played. New decoder integrated circuit chips are becoming available that implement the MacroVision standard, preventing unauthorized play of a copyrighted disk.
FIG. 1A
shows a laptop PC driving an external SVGA display. One of the earliest enhancements to laptop PCs was a port for an external cathode-ray tube (CRT) monitor. Laptop PC
20
is playing a copyrighted video from DVD disk
25
that is displayed on flat-panel display
22
. Flat-panel display
22
can be a dual-scan liquid-crystal display LCD or an active-matrix thin-film transistor display, or another technology. The image on the built-in flat-panel display
22
is replicated to an external-CRT port on the back of laptop PC
20
. External CRT monitor
24
is plugged into this external-CRT port, allowing the image to be viewed on external CRT monitor
24
. Newer laptop PCs allow the image to be simultaneously viewed on external CRT monitor
24
and flat-panel display
22
, while older laptop PCs disable flat-panel display
22
when the external CRT is in use.
Analog voltages representing the red, yellow, and blue color components of each pixel, and the horizontal and vertical sync pulses are output to the external-CRT port. Digital signals representing these pixels and sync clocks are sent to flat-panel display
22
. Thus the graphics controller inside laptop PC
20
must be capable of the format conversion.
Although the copyrighted video from DVD disk
25
can be viewed on external CRT monitor
24
, external CRT monitor
24
uses a computer-monitor format, such as super-VGA (SVGA), XGA, etc. Since SVGA format is not compatible with video-cassette recorders (VCRs), the copyrighted video cannot be easily recorded by a VCR despite being played on external CRT monitor
24
.
More recently, laptop PCs have been equipped with scan-converters for display on a television (TV).
FIG. 1B
shows a laptop PC driving a TV. The copyrighted video from DVD disk
25
is displayed on flat-panel display
22
. However, laptop PC
20
has a scan-line converter that converts the SVGA format displayed on flat-panel display
22
to the national television standards committee (NTSC) format used by televisions in the United States. Rather than convert to NTSC, some scan converters convert VGA into the phase-alternating-line (PAL) format common in Europe.
TV monitor
26
is a standard NTSC or PAL television receiver with a video-input port. TV monitor
26
gets its feed from the TV-OUT port of laptop PC
20
. The copyrighted video from DVD disk
25
is played on laptop PC
20
but visible on TV monitor
26
as well as flat-panel display
22
.
Illegal Tape Made by VCR Using Laptop PC's TV-OUT
FIG. 1C
shows that an illegal copy of a DVD disk played on a laptop PC can be made by connecting a VCR to the TV-OUT port of the laptop PC. An unscrupulous person or company could make illegal copy
29
of the video from DVD disk
25
. The is TV monitor is replaced with VCR
28
, which is connected to the TV-OUT port of laptop PC
20
. VCR
28
can make a video-cassette tape illegal copy
29
of DVD disk
25
playing on laptop PC
20
since laptop PC
20
formats the video's pixels in the NTSC or PAL formats for the TV-OUT port.
Some laptop PCs soon will include a MacroVision-compliant TV encoder that prevents unauthorized taping by blocking conversion to NTSC format. Most laptop PCs are not MacroVision compliant and do not block TV-conversion.
What is desired is a copyright-protection scheme for portable PCs. Software drivers for the graphics subsystem are desired that can operate with newer MacroVision-compliant TV encoders, and older scan-line converters that are not MacroVision-compliant. It is desired to block viewing of formats that can be copied by a VCR while allowing viewing in computer-monitor formats that are not easily taped.
SUMMARY OF THE INVENTION
A laptop personal computer (PC) prevents illegal copying of videos played on the laptop PC. A graphics controller generates a pixel stream in a computer-graphics format. The pixel stream is for display by a flat-panel display on the laptop PC. An S optical-disk player plays copyrighted optical disks. The optical-disk player outputs copy-protected videos to the graphics controller for display.
A TV encoder is coupled to receive the pixel stream from the graphics controller. It converts the computer-graphics format to a TV format. A video BIOS controls the graphics controller. The video BIOS has a scratch register for storing a flag indicating when the TV encoder is compliant with advanced copy-protection standards.
A display driver is coupled to the video BIOS. It also controls the graphics controller. The display driver also controls the TV encoder. A player application controls the optical-disk player. The player application includes a means for generating a request for copy protection to the display driver.
A copy-protection function in the display driver receives the request from the player application. The copy-protection function includes a 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.
A transmitting means in the display driver transmits an encryption key from the player application to the TV encoder when TV encoder can accept advanced copy-protection commands from the player application. An emulation means in the display driver disables 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. Thus copy-protection is emulated by the display driver for non-compliant TV encoders by disabling output from the TV encoder in the TV format.
In further aspects of the invention a plurality of player applications play a plurality of copy-protected videos. Each player application has a player identifier. A last-identifier register is readable by the display driver. It stores the player identifier for a last player application to enable copy protection. A compare means in the display driver compares the last-identifier register to the player identifier for a player application requesting copy protection. An error means in the display driver generates an error code and does not disable copy-protection by the TV encoder when the compare means does not signal a match. Thus only a last player application to enable copy protection can disable copy protection.
In other aspects a system registry stores system parameters. A TV flag in the system registry indicates when the TV encoder is disabled. The TV flag prevents other applicat
Auvinen Stuart T.
Chevalier Robert
NeoMagic Corp.
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