Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1998-01-06
2002-02-19
Garber, Wendy R. (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000, C386S349000
Reexamination Certificate
active
06349167
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical disc reproducing apparatus and method, and more particularly to an optical disc reproducing apparatus for displaying text such as caption data, program menu data, reproduction information, etc., on a display screen using a single character generating device.
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 is shown in FIG.
1
. This data stream includes a video stream, an audio stream, and a sub-picture stream. Although not shown, the data stream also includes control data which is used during reproduction to control the reproducing operation. The video stream includes video or image data such as for a moving image, the audio stream includes audio data such as voice and/or sound data, and the sub-picture stream includes caption data to be displayed on a display screen during reproduction. As also shown in
FIG. 1
, the audio data includes multiple channels.
A conventional optical disc reproducing apparatus using the above-described data stream structure will be described with reference to FIG.
2
. As shown in
FIG. 2
, 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 microprocessor
15
for controlling the operation of the servo circuit
13
, a signal processing circuit
5
, an error correction circuit
7
, a navigator
17
, and an on screen display (OSD) unit
31
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 data decoding section
30
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 VBR buffer
9
.
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
.
The OSD unit
31
, under the control of the microprocessor
15
, adds character data representing reproduction information to the analog video signal output by the first digital/analog converter
23
to produce an output video signal.
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 noise 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 microprocessor
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
. The error correction circuit
7
corrects errors generated in the reproduced signal in a predetermined manner as instructed by the microprocessor
15
. The error corrected reproduced signal is then output to and temporarily stored by the VBR buffer
9
. Based on the reproduction characteristics and the management and sub-management data, the navigator
17
controls the transfer of data from the VBR buffer
9
to the data decoding section
30
. Because frames of video data are compressed to different sizes according to the characteristics of the images in the frame, the quantity of data input by the VBR buffer
9
varies. In order to store variably transferred data, yet output a continuous and seamless stream of data, the VBR buffer
9
, under the control of the navigator
17
, is used.
As discussed above with respect to
FIG. 1
, the data output from the VBR buffer
9
includes system related control data, video data, sub-picture data, (e.g, caption and menu selection data), and audio data. The navigator
17
extracts the control data, and controls the operation of the data decoding section based in part thereon.
The data output from the VBR buffer
9
is received by the video decoding part
21
of the data d
Birch & Stewart Kolasch & Birch, LLP
Garber Wendy R.
LG Electronics Inc.
Onuaku Christopher
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