Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1997-12-22
2002-10-08
Tran, Thai (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000, C360S032000
Reexamination Certificate
active
06463208
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical disc reproducing apparatus and method using a variable transfer rate buffer to provide seamless play, and more particularly, to an optical disc reproducing apparatus which reduces the amount of information temporarily stored by the variable transfer rate buffer.
2. Description of Related Art
A greater demand exits in the industry for techniques which allow large amounts of information to be densely recorded upon recording media. Development has focused on recording media such as compact discs, digital video discs (DVD), etc., to meet this need.
A DVD reproducing apparatus has been designed to reproduce data recorded on a DVD (diameter:12 cm, thickness:1.2 mm) for about 135 minutes, and to provide better image and sound quality than a laser disc. Accordingly, a DVD device is one of the noticeable multi-media devices in audio/video and computer applications. DVDs are widely used in image processing applications due to their large storage capacity. One of the DVD system formats has system specifications as follows:
1. Maximum 9 camera angles reproducible;
2. Maximum 8 channels for audio and 32 languages as a caption;
3. Storage of a plurality of user selectable programs, selectable via a menu screen; and
4. Provision of parental lock function which can prevent children from watching adult programs.
According to the above system specification, the structure of the data stream used in DVDs includes video data, audio data, sub-picture data, and control data. The control data is used during reproduction to control the reproducing operation. The sub-picture stream includes, for example, caption data to be displayed on a display screen during reproduction.
As shown in
FIG. 2A
, one DVD format includes more than one program (title), represented by program chain data (PGCI), and each program is divided into a plurality of cells. As shown in
FIG. 2B
, each cell is divided into an integer number of video object unit(s) or VOBU(s). A VOBU is a basic unit of data for transfer. Each VOBU includes sectors which each store a predetermined range of video/audio data. As shown in
FIG. 2C
, the sector includes header data and main data (e.g., video/audio data). A VOBU consisting of a plurality of sectors stores a definite range of video/audio data in accordance with the system specification. Because the quantities of video/audio data included in the definite range of each VOBU are different from each other, the length of VOBUs varies and the number of sectors in VOBUs varies.
The programs, cells, VOBUs, and sectors include navigation data (system control data), i.e., header data. The header data includes position data. For instance, the header data for the sectors in a VOBU includes sequentially increasing identifiers (IDs), and the header data for a VOBU indicates the IDs for the first and last sector in the VOBU.
A conventional optical disc reproducing apparatus using the above-described data stream structure will be described with reference to FIG.
1
. As shown in
FIG. 1
, the optical disc reproducing apparatus for reproducing data from an optical disc
1
includes a motor
11
for rotating the optical disc
1
; an optical pick-up
3
for reading the data recorded on the optical disc
1
; a servo circuit
13
for generating drive signals to control the operation of the motor
11
and the optical pick-up
3
; and a microprocessor
15
for controlling the operation of the servo circuit
13
, a signal processing circuit
5
, an error correction circuit
7
, and a navigator
17
based on key input from a user.
In accordance with the instructions received from the microprocessor
15
, the signal processing circuit
5
amplifies the reproduced signal output from the optical pick-up
3
, and performs phase compensation thereon. The microprocessor
15
also obtains management and sub-management data from the reproduced signal processed by the signal processing circuit
5
. The management data includes table of contents (TOC) data such as recorded in the lead-in area of the optical disk
1
. The sub-management data includes characteristic information for the data recorded on the optical disk such as recorded in the headers of logically grouped data. With respect to a DVD, the characteristic information could indicate which camera angle from the plurality of camera angles the data in the following logical group represents, or could indicate that the data in the following logical group is English language caption data.
The error correction circuit
7
corrects, under the control of the microprocessor
15
, errors in the bit stream of the reproduced signal output by the signal processing circuit
5
. A variable transfer rate (VBR) buffer
9
temporarily stores the error corrected reproduced signal. The navigator
17
controls the transfer of data from the VBR buffer
9
to a dummy data removing section
33
in part based on control signals from the microprocessor
15
and in part based on the control data extracted from the bit stream of the reproduction signal output from the dummy data removing section
33
.
The dummy data removing section
33
removes dummy data added to the processed reproduced data during the error correction process. The dummy data removing section
33
transfers system data in the error corrected data, free of dummy data, to the navigator
17
, and transfers the reproduction data in the error corrected data, free of dummy data, to the data decoding section
30
under the control of the navigator
17
.
As shown in
FIG. 1
, the data decoding section
30
includes a video decoding part
21
, a graphics circuit
24
, and an audio decoding part
27
operating under the control of the navigator
17
. The graphics circuit
24
receives the output of the VBR buffer
9
via the video decoding part
21
, and the audio decoding part
27
receives the output of the VBR buffer
9
via the graphics circuit
24
and the video decoding part
21
.
A mixer
43
mixes the output of the video decoding part
21
and the graphics circuit
24
to produce a digital video signal. A first digital/analog converter
23
digital-to-analog converts the digital video signal, while a second digital/analog converter
29
digital-to-analog converts the output of the audio decoding part
27
. An NTSC/PAL encoder
31
converts the analog video signal output from the first digital/analog converter
23
into either the NTSC or PAL signal format.
Next, the operation of the conventional optical disc reproducing apparatus will be described. After mounting the optical disc
1
on a turntable (not shown), the user selects a specific system function and options associated therewith using a plurality of input keys (not shown). For instance after selecting a basic reproduction operation, the user can select the reproduction characteristics. The reproduction characteristics include, for example, the camera angle to be reproduced, that a caption should be displayed, and the language of the caption. If the user does not elect to select the reproduction characteristics, then the basic reproduction operation will proceed according to predetermined default reproduction characteristics.
When the user selects a reproduction operation, the microprocessor
15
controls the servo circuit
13
to drive the motor
11
and the optical pick-up
3
. According to the drive signals from the servo circuit
13
, the optical pick-up
3
reproduces data recorded on the optical disc
1
. The reproduced data is converted into an electrical signal and output to the signal processing circuit
5
. The signal processing circuit
5
performs a predetermined signal processing operation such as amplification, phase compensation, etc., on the electrical signal (i.e., the reproduced signal) in accordance with the instructions received from the microprocessor
15
, and the microprocessors
15
extracts the management and sub-management data from the processed reproduced signal.
The processed reproduced signal is output to the error correction circuit
7
as s
LG Electronics Inc.
Tran Thai
LandOfFree
Optical disc reproducing apparatus and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Optical disc reproducing apparatus and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical disc reproducing apparatus and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3000363