Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1997-12-24
2001-10-30
Tran, Thai (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000, C345S215000, C348S014160
Reexamination Certificate
active
06311014
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of digital video disk (DVD) systems, and more particularly to a universal audio/video interface for interfacing DVD electronics to a DVD player having an MPEG-2/AC-3 decoder or to a stereo DAC in a CD-ROM or DVD-ROM application.
BACKGROUND OF THE INVENTION
DVD systems have become popular in recent years as home video entertainment systems. DVD systems may also be used to record, store and provide data, such as computer and computing systems, in larger quantities than have heretofore been practicable with other storage devices, e.g., CD-ROM drives.
A conventional DVD system consists of DVD electronics which may be interfaced to a DVD player, a personal computer having a CD-ROM, and a DVD-ROM. Referring to
FIG. 1
, conventional DVD electronics
10
include photo diodes
11
which receive laser light reflected from a spinning, information-encoded disk and pass the received light to a preamplifier
12
which converts light from an optical signal to an electrical voltage representing the information encoded on the disk. The electrical signals output from the preamplifier are amplified and noise-filtered by channel interface
13
, which may be Channel Interface SSI 33P3725 manufactured by Silicon Systems, Inc. of Tustin, Calif. The channel interface
13
includes a built-in phase locked loop (PLL) which generates a data clock that is output, along with the amplified data, to data path controller
14
. Channel interface
13
also automatically controls the power of the laser scanning the disk and outputs a signal to a servo digital processor (DSP)
15
which indicates the focus and phase tracking of the laser.
Data path controller
14
decodes, corrects and stores the data received from the channel interface
13
in a DRAM buffer
18
for output, which will be described in detail later. Data path controller
14
generates and outputs a CLV signal to a servo DSP
15
. Based on this signal and the focus and tracking signals received from channel interface
13
, servo DSP
15
generates and inputs a control signal to motor drivers
16
that control the spindle motors spinning the disk, the movement of the laser read heads, and the focus of the laser (not shown). Servo DSP SSI 33H3825 and Data Path Controller SSI 33C3925 are examples of such devices.
The above-described DVD electronics configuration may be interfaced with a variety of devices including a DVD source decoder (MPEG-2/AC-3 decoder)
20
, an ATA packet interface (ATAPI) host
21
, and a stereo DAC
17
. Microcontroller
19
includes firmware that is programmed to implement the applicable interfaces. Various problems have arisen with prior art interfaces to the DVD Source Decoder.
For example, conventional interfaces have occupied a large number of pins on the data path controller chip (“pins” are terminals by which electrical signals are carried to/from a chip), which is undesirable in view of physical space limitations and increased design complexity. Further, a device interfaced to prior art DVD electronics may not be able to initiate a request for data from memory.
Interfaces in the prior art have also been prone to “lock-up,” which causes both the data path controller and the interfaced device to be placed in a wait state simultaneously and indefinitely. Lock-up occurs due to miscommunication during conventional “handshaking” procedures. In the usual scenario, a requesting device sends a request signal in the form of a pulse (a signal which changes from a low level to a high level for a short period of time and returns to the low level) and awaits an acknowledge signal from a source device. If, however, the request pulse is lost during transmission, the source device will never send its acknowledge signal and the requesting device will not know that its request pulse was lost. Even if the source device periodically samples the request signal to check for data requests, the lost pulse would not be detected because the signal on the data request line returned to the low level. The result is that both the requesting and source devices remain stalled, waiting for one another to send a signal.
What is desired is a simple, effective interface utilizing a small number of pins which allows a requesting device to initiate data requests and which avoids the phenomenon of lock-up.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a universal audio/video DVD-playback interface which interfaces in parallel to an MPEG-2/AC-3 decoder or serially to a stereo DAC in a CD-ROM or DVD-ROM application.
It is a further object of the present invention to provide a DVD-playback interface which utilizes a small number of pins and which allows a requesting device to initiate data requests.
It is a still further object of the present invention to provide a DVD-playback interface which avoids the phenomenon of lock-up.
To achieve the above objects, the present invention includes a source device interface including an input interface terminal at which a data request signal from an output device is received in a first mode and at which a sampling signal is received from the output device in a second mode; a first output interface terminal at which a sampling/synchronizing signal is transmitted from the source device to the output device in the first mode, the sampling/synchronizing signal synchronizing and sampling the data request signal, and at which a first synchronizing signal is transmitted from the source device to the output device in the second mode, the first synchronizing signal synchronizing data output; at least one data output interface terminal at which requested data is transmitted from the source device to the output device in the first and second modes, a second output interface terminal at which a second synchronization signal is transmitted from the source device to the output device at the start of data transmission in the first mode; a third output interface terminal at which a data strobe signal is transmitted from the source device to the output device in the first mode, the data strobe signal latching the requested data, and at which a third synchronization signal is transmitted from the source device to the output device in the second mode, the third synchronization signal synchronizing the left/right audio frames; and a fourth output terminal at which a data error signal is transmitted from the source device to the output device in the first and second modes, the data error signal indicating that the requested data contains an error.
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Nguyen Loc
Zhu Li
Brady III Wade James
Swayze, Jr. W. Daniel
Telecky , Jr. Frederick J.
Texas Instruments Incorporated
Tran Thai
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