JP2675658B2 - LD-ROM playback system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an LD-ROM playback system used as a home audio / video playback system or the like.

(Prior Art) Recently, an LD (laser disk) playback system is becoming widespread as a home audio / video playback system.

As an advanced version of this LD, digital data of the same standard as a CD-ROM was superimposed on analog data consisting of analog video data and audio data and recorded on the same track.
There is an LD-ROM. As the digital data to be superimposed, a computer program, digital audio data, ADPCM audio data, or the like is scheduled. The reproduction of the analog data and the digital data is performed based on frequency division in a common reproducing head for both analog and digital.

(Problems to be Solved by the Invention) Since the convenience of the LD-ROM reproduction system largely depends on digital data recorded by being superimposed on analog data, intensive studies are being made. The inventor has
As a result of the study, we came up with the moving image data to be combined with the analog moving image and displayed as the digital data.
That is, the subtitle screen that fits into the display screen of the playback analog video, the wide aspect signal for expanding the left and right sides of the display screen of the playback analog video, the signer's figure, or the game console, switch to the analog video display screen. A special scene to be displayed (for example, if the analog moving picture is a scene of a car in motion, a scene of a crash and flaming when the steering wheel operation fails) is considered.

Usually, to record a moving image as digital data,
From the viewpoint of recording capacity and disk read speed, it is necessary to perform multi-stage data compression by combining various data compression methods. Typical multi-stage compression data compression methods include interframe predictive coding, discrete cosine transform (DCT), transform coefficient quantization (Q), and quantized coefficient variable length coding (VLC). There are things that are applied in sequence. In such data compression, the amount of data for one frame fluctuates significantly with inter-frame predictive coding and variable-length coding. For this reason, a considerable measure is required to reproduce the compressed moving image data while synchronizing with the analog moving image data in which the data amount of each frame is constant for synthesizing display.

(Means for Solving the Problem) According to the LD-ROM reproducing device of the present invention, the LD-R to be reproduced is
In place of the conventional analog audio signal, the OM contains a composite control signal and digitally compressed moving image data of the CD-ROM standard that has been subjected to data compression is superimposed on the analog moving image data, and this LD-ROM is a CAV type. Is configured as.

This CD-ROM reproducing device is a CAV type LD-ROM in which a digital compressed moving image data compressed by high-efficiency encoding as a digital data and a digital data string including a synthesis control signal are recorded, and from this LD-ROM, A first reproducing head for reproducing analog moving image data, an analog moving image data demodulation section for demodulating an output of the first reproducing head, and a first reproducing head for reproducing a digital data string including the digital compressed moving image data from the LD-ROM. Two reproducing heads, and a digital moving image data demodulating section for decoding digital compressed moving image data from the output of the second reproducing head,
A buffer memory installed between the digital moving picture data demodulation section and the second reproducing head, a reproduction control means for stopping the reproducing operation of the second reproducing head when the buffer memory overflows, and the analog moving picture data. And a synthesizing unit that synthesizes the moving image data demodulated by each of the demodulation unit and the digital moving image data demodulation unit based on the synthesis control signal and supplies the synthesized data to the display unit.

Further, the combination control signal is a signal for designating a gradation range of the digital compressed moving picture data, and the composition means has a gradation of the digital compressed moving picture data within a range of gradation specified by the composition control signal. Only, the digital compressed moving image data is selected and supplied to the display section.

That is, according to the LD-ROM reproducing device of the present invention, (i) an independent reproducing head is independently provided for reproducing analog moving image data in which the data amount of each frame is constant and digital compressed moving image data in which the data amount is different for each frame. (Ii) The CAV type allows the simultaneous reproduction of different heads on different tracks. (Iii) The buffer memory is installed between the digital compressed moving image demodulation unit and the second reproducing head. At the same time, a reproduction control means for stopping the reproduction operation of the second reproduction head when the buffer memory overflows is provided. (Iv) Digital compressed moving picture data synthesis control signal is included and demodulated analog and digital moving picture data By providing a synthesizing means for synthesizing on the basis of the synthesis control signal, it becomes possible to play back both video data synchronously. To realizes a synthesis of both screens the analog system and the digital system by the simple configuration of operation of the digital video system only.

 Hereinafter, the operation of the present invention will be described in detail with examples.

(Embodiment) FIG. 1 is a block diagram showing a configuration of an LD-ROM reproducing system according to an embodiment of the present invention, wherein reference numerals 1 and 2 denote reproducing heads and 3, 4.
Is an amplifier, 5 and 6 are separation units, 7 is an analog video data demodulation unit, 8 is an analog audio data demodulation unit, 9 is a digital audio data demodulation unit, 10 is a buffer memory, 11 is a digital compressed video data demodulation unit, and 12 is Digital audio data demodulation unit, 13 is a synthesis unit, 14 is a system control unit, 15 is a mechanism control unit, 17 is a demodulated analog video data output terminal, 18 is a demodulated analog audio data output terminal, and 19 is a digital digital An output terminal 20 is an LD-ROM.

The reproducing heads 1 and 2 are arranged at a distance of about 180 ° in the circumferential direction in order to avoid overlapping of the reproducing positions. Control of the radial reproducing position of the reproducing heads 1 and 2 is performed by a system control unit 14 and a mechanism control unit 15.

From the reproduction head 1, in addition to the analog moving image data and analog audio data recorded on the LD-ROM 20, digital data such as known CD audio data and ADPCM audio data recorded superimposed on the same track. Is played. After the output of the reproducing head 1 is amplified by the amplifier circuit 3, the output is separated by the separation unit 5 and supplied to the analog moving image data demodulation unit 7, the analog audio demodulation unit 8, or the digital audio demodulation unit 9. If the uncompressed digital data reproduced by the reproducing head 1 is other than audio data such as a computer program, the digital data is branched before the digital audio data demodulation unit 9 and output to the output terminal 19.

On the other hand, the reproduction head 2 reproduces digital compressed moving image data recorded on the LD-ROM 20. This digital compressed moving image data is created by multi-stage data compression combining inter-frame predictive coding, discrete cosine transform (DCT), quantization of transform coefficients (Q), and variable length coding of quantized coefficients (VLD). I have.

FIG. 2 is a data format diagram exemplifying the structure of this digital compressed moving image data, and the data of each frame is composed of digital compressed moving image data and digital audio data. The beginning digital compressed moving image data of each frame or a plurality of consecutive frames includes a synthesis control signal. This synthesis control signal will be described in detail later. The digital compressed moving image data and the digital audio data are amplified by the amplifier 4 and then separated from the analog data by the separation circuit 6, and the buffer memory 10
Is written to. The digital compressed moving image data and the digital audio data are read while being separated by the buffer memory 10, demodulated by the compressed moving image data demodulation unit 11 and the digital audio data demodulation unit 12, respectively, and converted into analog data. The demodulated digital moving image data is combined with the demodulated analog moving image data based on the combining control signal in the combining unit 13, and is supplied to the display unit (not shown) via the output terminal 17. The demodulated digital audio data is supplied to a speaker (not shown) via the switch 16 and the output terminal 18.

As illustrated in FIG. 2, the data of each frame, in particular, the compressed moving image data, has a degree of correlation with the immediately preceding frame,
It varies greatly due to the compression efficiency of variable length coding. Therefore, during the reproducing operation, the transfer speed of the reproduced data output from the reproducing head 2 is constant, while the data amount of the compressed moving image demodulating unit 11 to be received within a fixed time (receiving Speed) fluctuates.
In order to buffer the mismatch between the transfer speed and the reception speed, a buffer memory 10 is provided between the separation unit 6 and the demodulation units 11 and 12.
Is installed.

When the buffer memory 10 overflows, the reproducing operation of the reproducing head 2 is stopped under the control of the built-in read / write control unit until the data amount falls below a predetermined value. However, in the synchronous playback operation mode of the analog moving image data and the digital compressed moving image data, the buffer memory 10
Even if the reproducing operation of the reproducing head 1 is interrupted due to the overflow of the, the rotation of the laser disk LD and the reproducing operation of the reproducing head 1 are continued. Also, this laser disc is CA
Because of the V-shape, even if the reproducing heads 1 and 2 are displaced in the radial direction, the constant speed rotation operation is maintained, and normal reproduction is performed.

Although the overflow of the buffer memory 10 and the interruption of the reproducing operation of the reproducing head 2 due to the overflow also occur during the slow motion reproduction of the compressed moving image, the reproduction from the reproducing head 1 is continued regardless of the cause of the overflow. Needless to say.

FIG. 3 is a block diagram showing an example of the configuration of the synthesizing unit 13 in FIG. 1, in which 21 and 22 are frame memories, 23 is a selector, 24a and 24b are registers, 25a and 25b are comparison circuits, and 26 is an AND circuit. It is a gate.

The input terminal 31 is supplied with the demodulated analog moving image signal output from the analog moving image demodulating unit 7 in FIG.
This analog moving image signal is supplied to one input terminal of the selector 23 via the frame memory 21. On the other hand, the input terminal 32 is supplied with the demodulated digital moving image signal output from the digital compressed moving image demodulating section 11 in FIG. This digital moving image signal is supplied to the other input terminal of the selector 23 via the frame memory 22. Further, the synthesis control signal output from the digital compressed moving image demodulating unit 11 is supplied to the input terminals 33 and 34. These combined control signals are held in registers 24a and 24b, respectively.

The synthesis control signals held in the registers 24a and 24b specify the upper limit value and the lower limit value of the gradation signal, respectively. Comparison circuit 25
a compares the gradation of the moving image data output from the frame memory 22 with the upper limit of the gradation held in the register 24a,
If the gradation of the moving image data is less than or equal to this upper limit value, the output is raised to high, otherwise it is kept low. The comparison circuit 25b is
The gradation of the moving image data output from the frame memory 22 is compared with the lower limit value of the gradation held in the register 24b, and if the gradation of the moving image data is equal to or higher than this lower limit value, the output is raised to high, etc. In case of keep low. Therefore, the frame memory
The output of the AND gate 26 becomes high only when the gradation of the moving image data output from 22 is stored between the upper limit value and the lower limit value. The selection state of the selector 23 receiving the output of the AND gate 26 is switched when this output becomes high, and the moving image data output from the frame memory 22 is selected and output to the output terminal 36 connected to the display unit.

Although detailed illustration is omitted to avoid complication, the registers 24a, 24b and the comparison circuits 25a, 25b are installed for each component of R, G, B, and the gradation is set for each of R, G, B components. The upper and lower limits of are set. Further, it is determined whether or not the moving image data output from the frame memory 22 exists between the upper limit value and the lower limit value for each of the R, G, B components. Therefore, create a specific combination of gradations of digital moving image data R, G, B, and limit the range specified by the upper limit value and the lower limit value of the composite control signal to a narrow range including this specific combination. Thus, this moving image data can be displayed by being superimposed on the analog moving image data. The input terminal shown in Fig. 3
Reference numeral 35 is for the user to control the synthesizing unit 13 via the system control unit 14 of FIG.

FIG. 4 is a block diagram illustrating another configuration of the combining unit 13 of FIG.

The synthesizing unit 13 is similar to the synthesizing unit shown in FIG.
, An address addition circuit 29, and an input terminal 37 for receiving the address addition value from the system control unit.
In this synthesizing unit, the other components designated by the same reference numerals as those in FIG. 3 are the same as those already described with reference to FIG. 3, and a duplicate description thereof will be omitted.

The user operates the input means such as a remote controller to cause the system control unit 14 to shift the display position of the composite screen in the water / vertical direction. This shift command is
For example, it is performed by pressing down a shift button formed on the remote controller in the horizontal and vertical directions. Upon receiving this shift command, the control unit 14 generates an address addition value having a size proportional to the pressing time of the horizontal / vertical shift button, and the address addition value is set to the fourth value.
It is supplied to the address adder circuit 29 via the input terminal 37 in the figure. Address adder circuit 29 that received this address add value
Adds the address addition value in the horizontal and vertical directions to the read address of the frame memory 28 and supplies it to the frame memory 22 as a write address. Along with this, the writing position of the digital image data on the frame memory 22 is changed, and the display position on the composite screen is shifted in the horizontal and vertical directions according to the user's wishes.

(Effects of the Invention) As described in detail above, the LD-ROM reproduction system of the present invention includes (i) analog moving image data in which the data amount of each frame is constant and digital compressed moving image data in which the data amount differs for each frame. A dedicated reproducing head is independently provided for reproduction, (ii) the CAV type is adopted to allow simultaneous reproduction on different tracks of each head, and (iii) the digital compressed moving image demodulating unit and the second reproducing head. A buffer memory is provided between them, and a playback control means for stopping the playback operation of the second playback head when the buffer memory overflows is provided, and (iv) the digital compressed moving image data includes a synthesis control signal. Since the demodulated analog and digital moving image data are combined with each other on the basis of this combination formation control signal, the combining means is provided. Reproduced together it is possible, specific effect of realizing the synthesis of each video screen by a simple configuration that the operation of the digital video system only is exhibited.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the structure of an LD-ROM reproducing system according to an embodiment of the present invention, and FIG. 2 is a data format diagram illustrating the structure of digital compressed moving image data to be reproduced.
FIG. 3 is a block diagram showing an example of the configuration of the synthesizing unit 13 in FIG. 1, and FIG. 4 is a block diagram showing another example of the configuration of the synthesizing unit 13 in FIG. 1,2 ... reproducing head, 3,4 ... amplifying circuit, 5,6 ... separator, 7 ... analog video data demodulator, 8 ... analog audio data demodulator, 9 ... digital audio data demodulator , 10: buffer memory, 11: digital compressed moving image data demodulator, 12: digital audio data demodulator, 13
…… Synthesis unit, 14 …… System control unit, 15 …… Mechanism control unit, 17 …… Analog video data output terminal, 18 …… Analog audio signal output terminal, 19 …… Digital data output terminal, 20 ・ ・ ・… Laser disk, 21,22,28 …… Frame memory, 23 …… Selector, 24a, 24b …… Register, 25a, 2
5b …… Comparison circuit, 29 …… Address addition circuit.

Claims (2)

(57) [Claims] 1. An LD for reproducing an LD-ROM in which digital data of the CD-ROM standard is superimposed on analog moving image data and recorded.
-In a ROM playback system, digital compressed video data compressed by high-efficiency encoding as digital data and a CAV-type LD-ROM in which a digital data string containing a synthesis control signal is recorded, and the analog video data from this LD-ROM A first reproducing head for reproducing the data, an analog moving image data demodulating section for demodulating the output of the first reproducing head, and a second reproducing for reproducing a digital data string including the digital compressed moving image data from the LD-ROM. A head, a digital moving picture data demodulation section for decoding digital compressed moving picture data from the output of the second reproducing head, and a buffer memory provided between the digital moving picture data demodulating section and the second reproducing head. Playback control for stopping the playback operation of the second playback head when the buffer memory overflows And a synthesizing unit that synthesizes the moving image data demodulated by the analog moving image data demodulation unit and the moving image data demodulated by the digital moving image data demodulation unit based on the synthesis control signal, and supplies the synthesized data to the display unit. LD-ROM playback system. 2. The synthesizing control signal is a signal for designating a gradation range of the digital compressed moving picture data, and the synthesizing means sets the gradation of the digital compressed moving picture data within a range of the gradation designated by the synthesizing control signal. Only if it exists
The LD- according to claim 1, characterized in that digital compressed moving image data is selected and supplied to the display unit.
ROM playback system.