Multi-rate optical disc recording and reproducing apparatus

Multi-rate optical disc recording method and apparatus wherein data are recorded on the optical disc in accordance with a transfer rate of data, thereby preventing an unnecessary waste of a storage area in the optical disc and also enhancing a recording time of the optical disc. Said method and apparatus exploit a transfer rate detector for detecting a transfer rate of a digital signal generated at a digital signal source. This transfer rate detector allows a rotation velocity controller to rotate the optical disc at a speed corresponding to the transfer rate of the digital signal, in response to the transfer rate of the detected digital signal. Also, the transfer rate detector allows a recording portion to record the digital signal on the optical disc at the detected transfer rate.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an optical disc recording and reproducing 
apparatus that optically accesses the optical disc, and more particularly 
recording method and apparatus of a multi-rate optical disc wherein the 
optical disc can be adaptively driven based on a transfer rate of data to 
be recorded. 
2. Description of the Prior Art 
In a conventional optical disc recording and reproducing apparatus, light 
beams are irradiated onto the optical disc such as Compact Disc (CD) and 
Digital Versatile (or Video) disc (DVD) in order to access data. Such 
optical discs record binary data representing audio signals, video 
signals, text information, etc. 
Digital signals recorded onto the optical disc and reproduced therefrom 
include various recording signals such as a video signal, an audio signal, 
digital data or a digital broadcasting program including a combination of 
all of said signals, etc. Each of these signals has a different data 
quantity, for example digital bit quantity per second, respectively. Also, 
in the same broadcasting program, the data quantity is different according 
to the attribute of a broadcasted program. Specifically, the data quantity 
is about 6 to 7 Mbps in the case of a sports program, whereas the data 
quantity is generally about 3 to 4 Mbps in the case of a movie program. 
Moreover, the data quantity may differ according to the number of pixels 
of a program being provided. Specifically, the data quantity is about 5 to 
6 Mbps in the case of the existed NTST and signals having an array of 
about 720.times.480 pixels (normal video signal hereinafter), whereas the 
data quantity is generally about 10 to 15 Mbps in the case of a high 
density signal having an array of 1024.times.1024 pixels (high resolution 
signal hereinafter). Optical disc apparatuses must therefore be capable of 
recording and reproducing digital programs having such various data 
quantities. 
However, a conventional optical disc has only a single-rate recording 
means. The following is a description of an example of a conventional 
optical disc recording and reproducing apparatus, which records and 
reproduces the normal video signal of 5 Mbps and the high resolution 
signal of 10 Mbps to/from a conventional optical disc. The conventional 
optical disc recording and reproducing apparatus drives the optical disc 
at a transfer rate of 10 Mbps on the optical disc. Consequently, when 
recording the high resolution video signal of 10 Mbps in a real time, the 
conventional optical disc recording and reproducing apparatus can exploit 
the entire recording area of the optical disc, that is, 100% of recording 
area in the optical disc. By contrast, when recording the normal video 
signal of 5 Mbps in real time, the conventional optical disc recording and 
reproducing apparatus wastes half the record area, that is, 50% of record 
area in the optical disc unnecessarily. Such a conventional optical disc 
recording and reproducing apparatus also wastes the recording area 
unnecessarily when recording the audio signal and the text signal with 
different transfer rates. 
For reference, the following describes the process in which the high 
resolution video signal and the normal video signals are recorded, 
respectively, using the optical disc recording and reproducing apparatus. 
FIG. 1 is a time chart for explaining the process in which the high 
resolution video signal of 10 Mbps is recorded by the optical disc 
recording and reproducing apparatus. The frame dividing signal FDS shown 
in FIG. 1 assigns odd number and even number frames of the video signal. 
The high logic region and the low logic region of the frame dividing 
signal FDS represent the odd number frames and the even number frames, 
respectively. The high resolution video data divided into frame units 
according to this frame dividing signal is inputted to optical disc 
recording and reproducing apparatus at a rate of 10 Mbps. Then, the 
optical disc recording and reproducing apparatus formats the high 
resolution video signal HVD in a certain form required by an optical disc, 
and records on the optical disc. At this time, the optical disc is rotated 
at a constant velocity by the optical disc recording and reproducing 
apparatus like DSS shown in FIG. 1. As a result of this, an information 
pit train IPT is formed on the information track of the optical disc 
having frame video data pits arranged continuously, as shown in FIG. 1. 
FIG. 2 is a time chart for explaining the process in which the normal 
resolution video signal of 5 Mbps is recorded by the optical disc 
recording and reproducing apparatus. In FIG. 2, the normal video data NVD 
are divided into frame units by the frame dividing signal FDS. This normal 
video data is inputted to the optical disc recording and reproducing 
apparatus at a transfer rate of 5 Mbps, and formatted, like FNVD in FIG. 
2, by the optical disc recording and reproducing apparatus. The formatted 
normal video data FNVD consists of compressed frame video data and null 
data inserted between the compressed frame video data. These null data are 
generated because the normal video data NVD of 5 Mbps is temporally 
compressed into 1/2 by the optical disc recording and reproducing 
apparatus operating at a rate of 10 Mbps. In turn, the formatted normal 
video data FNVD are recorded on the optical disc using the optical 
recording and reproducing apparatus. At this time, the optical disc 
rotates at the same velocity used to record the high resolution video 
data. As a result of this, an information pit train IPT is formed on the 
information track of the optical disc in which video data pit regions and 
null data pit regions are arranged alternately. 
As described above, the conventional optical disc recording and reproducing 
apparatus causes the null data to be recorded on optical disc because it 
records data on the optical disc at a fixed transfer rate, regardless of 
the transfer rate of data. The conventional optical disc recording and 
reproducing apparatus therefore wastes the recording area of the optical 
disc unnecessarily. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide multi-rate optical disc 
recording method and apparatus which can prevent the unnecessary waste of 
the storage area of optical disc by recording data on the optical disc in 
response to the transfer rate of data. 
In order to obtain the above object, a multi-rate optical disc recording 
method according to one aspect of the present invention comprises steps of 
detecting a transfer rate of the digital signal, controlling a rotation 
velocity of the optical disc in accordance with the transfer rate of the 
digital signal, and recording the digital signal on the optical disc. 
A multi-rate optical disc recording method according to another aspect of 
the invention comprises steps of setting a recording speed of the digital 
signal, controlling a rotation velocity of the optical disc in accordance 
with the recording speed, converting a transfer rate of the digital signal 
in accordance with said recording speed, and recording the converted 
digital signal on the optical disc. 
A multi-rate optical disc recording method according to another aspect of 
the invention, in an optical disc recording apparatus for accessing an 
optical disc optically, comprises steps of detecting a transfer rate of a 
first digital signal generated from a digital signal source, rotating the 
optical disc at a speed corresponding to the transfer rate of the first 
digital signal, deciding whether a second digital signal was recorded on 
the optical disc or not, and recording the first digital signal from a 
final position of the second digital signal in the optical disc. 
A multi-rate optical disc recording method according to still another 
aspect of the invention, in an optical disc recording apparatus including 
an optical pickup for accessing a spiral information track on an optical 
disc optically, comprises steps of detecting a transfer rate of a first 
digital signal generated from a digital signal source, rotating the 
optical disc at a speed corresponding to a transfer rate of the first 
digital signal, deciding whether a second digital signal was recorded on 
the optical disc or not, comparing whether a transfer rate of the second 
digital signal is identical to that of the first digital signal, changing 
a rotation velocity of the optical disc into a speed corresponding to the 
transfer rate of the second digital signal, detecting a final position of 
the second digital signal on the information track and information about 
the final position, changing the rotation velocity of the optical disc 
into the speed corresponding to the transfer rate of said first digital 
signal, waiting until the rotation velocity of the optical disc arrives at 
the speed corresponding to the transfer rate of the first digital signal, 
jumping reversely the optical pickup into a position prior to the final 
position of the second digital signal, and applying the first digital 
signal to the optical pickup to record it on the optical disc. 
Further, a multi-rate optical disc recording apparatus according to one 
aspect of the present invention comprises means for detecting a transfer 
rate of a digital signal from a digital signal source, optical disc 
driving means for rotating the optical disc in response to the transfer 
rate of the digital signal detected by the transfer rate detecting means, 
and means for recording the digital signal on the optical disc at the 
transfer rate detected by the transfer rate detecting means. 
A multi-rate optical disc recording apparatus according to other aspect of 
the present invention comprises means for recording a digital signal from 
a digital signal source on an optical disc, record mode determining means 
for a recording speed of the digital signal, and means for controlling a 
rotation velocity of the optical disc in response to the recording speed 
determined by the record mode determining means. 
A multi-rate optical disc recording apparatus according to another aspect 
of the present invention comprises means for detecting a transfer rate of 
a digital signal from a digital signal source, optical disc driving means 
for rotating the optical disc in response to the transfer rate of the 
digital signal detected by the transfer rate detecting means, and means 
for recording the digital signal on the optical disc at the transfer rate 
detected by the transfer rate detecting means. 
A multi-rate optical disc recording apparatus according to still another 
aspect of the present invention comprises means for detecting a transfer 
rate of a digital signal from a digital signal source, buffer means for 
storing the digital signal from the digital signal source temporarily, 
variable clock generating means for generating a clock signal of variable 
frequency, disc driving means for rotating the optical disc, means for 
recording a digital signal stored in the buffer means on the optical disc 
in response to the clock signal from the variable clock generating means, 
and means for controlling the variable clock generating means and the disc 
driving means in response to the transfer rate detected by the transfer 
rate detecting means to control a frequency of the clock signal and a 
rotation velocity of the optical disc.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 3, there is shown an optical disc recording and 
reproducing apparatus according to the preferred embodiment of the present 
invention which comprises a transfer rate detector 10 and a buffer 12 
commonly connected an input/output line 11. The input/output line 11 is 
connected to a data source (not shown) in order to transfer the video data 
VDS from the data source into the buffer 12 or to transfer the video data 
VDS from the buffer 12 into the data source. This video data VDS is 
transferred in the shape of frame unit, as shown in FIG. 5 according to 
the frame dividing signal FDS. The frame video data consists of only data 
portions including information about pixels, or of both identification 
code portions including information about a transfer rate and data 
portions including information about pixels. The video data is classified 
into high resolution video data HVD and normal video data NVD in 
accordance with the number of pixels. The high resolution video data HVD 
is formed by formatting an array of 1024.times.1024 pixel data to one 
frame and making a moving picture compression of the formatted frame video 
data, which are transferred at a transfer rate of 10 Mbps. The normal 
video data NVD is formed by formatting an array of 325.times.525 pixel 
data to one frame, which is transferred at a transfer rate of 5 Mbps. The 
transfer rate detector 10 detects a transfer rate value of video data VDS 
from the identification portion included in the video data VDS from the 
input/output line 11. The transfer rate value is detected by the transfer 
rate detector 10 only when the identification code portion is included in 
the video data VDS. The buffer 12 temporarily stores the video data VDS 
inputted from the input/output line 11 and the reproduced video data to be 
transferred toward the input/output line 11. The buffer 12 has enough 
storage capacity to store two frame video data. 
The optical disc recording and reproducing apparatus further comprises a 
key input portion 14 for sending an instruction assigned by a user via the 
first node 13 to microcomputer 16, a clock frequency change portion 18 
connected to the microcomputer 16, and a rotational velocity control 
portion 20. The key input portion 14 inputs recording, reproducing and 
retrieval instructions from a user as well as virtual addresses intended 
to record and reproduce, and supplies the inputted instructions and 
addresses to the microcomputer 16 via the first node 13. Also, during 
recording, the key input portion 14 inputs a transfer rate value related 
to the data to be recorded, and supplies the transfer rate value to the 
microcomputer 16. For this purpose, the key input portion 14 includes key 
switches (not shown) and/or a keyboard. 
In the recording mode, the microcomputer 16 generates clock frequency data 
and rotational velocity data in accordance with a transfer rate value 
inputted via the second node 15 from the transfer rate detector 10. Also, 
the microcomputer 16 generates the clock frequency data and the rotational 
velocity data corresponding to the transfer rate value from the key input 
portion 14 when the transfer rate value is not detected by the transfer 
rate detector 10. The clock frequency data is supplied to the clock 
frequency change portion 18 via the third node 17, and the rotational 
velocity data is supplied to the rotation velocity control portion 20 via 
the fourth node 19. 
The clock frequency change portion 18 varies the frequency of the clock 
signal generated at a clock generator 22 in accordance with a logic value 
of the clock frequency data applied via the third node 17 from the 
microcomputer 16. The clock generator 22 generates the first clock signal 
FCS or the second clock signal SCS under control of the clock frequency 
change portion 18. The first clock signal FCS is generated when the video 
data VDS is inputted to the input/output line 11 at a transfer rate of 5 
Mbps, which has a frequency of 5 MHz. For this, the clock generator 2 
includes a voltage controlled oscillator (not shown), and the clock 
frequency change portion 18 includes a decoder (not shown) such as a 
digital-to-analog converter. 
On the other hand, the rotational velocity control portion 20 rotates a 
spindle motor 14 at a speed corresponding to the rotational velocity data 
inputted via the fourth node 19 from the microcomputer 16. For example, 
the rotational velocity control portion 20, like DSV in FIG. 4, rotates 
the spindle motor 24 at a speed of 100 rps when the high resolution video 
data HVD of 10 Mbps is inputted to the input/output line 11. By contrast, 
rotational velocity control portion 20 rotates the spindle motor 24 at a 
speed of 50 rps when the normal video data NVD is inputted to the 
input/output line 11. In response to rotation of the spindle motor 24, the 
optical disc D is subject to rotate at a same velocity as the spindle 
motor 24. 
Furthermore, the optical disc recording and reproducing apparatus comprises 
a formatter 26 connected with the buffer 12 in serial, a digital signal 
processor 28 (DSP hereinafter), and a channel modem 30. The formatter 26 
formats the video data VDS from the buffer 12 into a pattern required by 
an optical disc D and, at the same time, applies the formatted video data 
to the buffer 12. Also, the formatter 26 reversely formats the reproduced 
video data from the DSP 28 into the original pattern and applies the 
reversely formatted video data to the buffer 12. The formatter 26 inputs 
the video data VDS stored in the buffer 12 at a rate of 10 Mbps or 5 Mbps 
in accordance with the clock signal from the clock generator 22. 
Specifically, the formatter 26 inputs the video data VDS from the buffer 
12 at a rate of 10 Mbps when the first clock signal FCS is applied from 
the clock generator 22, while it inputs the video data VDS from the buffer 
12 at a rate of 5 Mbps when the second clock signal SCS is applied from 
the clock generator 22. 
Under control of the microcomputer 16, DSP 28 converts the video data from 
the formatter 26 into the form of a data bit stream or restores the video 
data from the reproduced data bit stream. Specifically, in the recording 
mode, DSP 28 detects a synchronous pattern and an address from a support 
signal demodulated from the channel modem 30, and supplies the detected 
synchronous pattern and address to the microcomputer 16. Also, DSP 28 
converts the formatted video data from the formatter 26 into the form of a 
data bit stream. This data bit stream is to be added by an error 
correction code, an address and a synchronous pattern besides the video 
data, which is supplied to the channel modem 30. The support signal is a 
signal which is preformatted on the track in the optical disc, and 
includes a synchronous pattern indicating the rotation velocity of the 
optical disc D and an address indicating the physical position of the 
storage area In the reproduction mode, DSP 28 separates a video data, an 
error correction code, a synchronous pattern and an address from the 
reproduced data bit stream from the channel modem 30 and corrects an error 
generated in the video data by the error correction code. Also, DSP 28 
applies the error corrected video data to the formatter 26 and supplies 
the synchronous pattern and the address to the microcomputer 16. 
In the recording mode, the channel modem 30 channel-codes a data bit stream 
to be recorded from the DSP 28, and channel-decodes a support signal 
reproduced from the optical disc D and received through reproducing 
portion 36 and optical pickup 32. The channel-decoded support signal is 
applied to the DSP 28. In the reproduction mode, the channel modem 30 
channel-decodes a data bit stream reproduced from the optical disc and 
supplies the channel-decoded data bit stream to DSP 28. 
The optical disc recording and reproducing apparatus further comprises an 
optical pickup device 32 for accessing the optical disc D optically, and a 
recording portion 34 and a reproducing portion 36, which are connected 
between the channel modem 30 and the optical pickup device 32. Under 
control of the microcomputer 16 the optical pickup device 32 moves back 
and forth in a radial direction of the optical disc to record data on the 
track in the optical disc D or pick up information recorded on the track 
in the optical disc D. For this purpose, the optical pickup device 32 
irradiates a relatively large energy of light beam onto the surface of the 
optical disc D in the recording mode. By contrast, it radiates a 
relatively small energy of light beam onto the surface of the optical disc 
D in the reproduction mode. 
The recording portion 34 allows a light beam irradiated on the track in the 
optical disc D to be switched by controlling the optical pickup device 32 
in accordance with the data bit stream from the channel modem 30. As a 
result, a data pit train WDP indicating "1" or "0" in accordance with the 
data bit stream is formed in such a manner that a spiral track is shaped 
in the optical disc D. In this data pit train WDP, HVDP represents the 
data pit train relative to one frame of high resolution video data and 
NVDP does the data pit train relative to one frame of normal video data. 
The reproducing portion 36 processes a high frequency signal from the 
optical pickup device 32 to generate a support signal and a data bit 
stream from the high frequency signal. The support signal and the data bit 
stream generated at the reproducing portion 36 are supplied to the channel 
modem 30. 
FIG. 6 is a flow chart for explaining a multi-rate recording method 
according to the first embodiment of the present invention. The process in 
FIG. 6 is performed by the microcomputer 16. 
Referring now to FIG. 6, in step 40, the microcomputer 16 waits until a 
record instruction is inputted from the key input portion 14. If the 
record instruction is inputted in step 40, then the microcomputer 16 sets 
a record mode flag assigned in a part of register therein, and inputs a 
transfer rate value of video data from the transfer rate detector 10 (step 
42). 
In step 44, the microcomputer 16 decides, based on the transfer rate value, 
if the video data VDS on the input/output line is high resolution video 
data HVD or normal video data NVD. When the transfer rate value is 10 
Mbps, the microcomputer 16 decides that the high resolution video data HVD 
is being applied to the input/output line 11. When the transfer rate value 
is 5 Mbps, the microcomputer 16 decides that the normal video data NVD is 
being applied to the input/output line 11. 
If it is decided that the high resolution video data HVD is applied to the 
input/output line 11 in step 44, then the microcomputer 16 allows the 
clock generator 22 to generate the first clock signal FCS of 10 MHz by 
controlling the clock generator 22 via the clock frequency change portion 
18 (step 46). At this time, the formatter 26 inputs the high resolution 
video data HVD in the buffer 12 at a rate of 10 Mbps, by means of the 
first clock signal from the clock generator 22. As a result, the high 
resolution video data HVD recorded on the optical disc D is transferred at 
a rate of 10 Mbps by way of the formatter 26, the DSP 28, the channel 
modem 30, the recording portion 34 and the optical pickup device 32. 
Subsequently, the microcomputer 16 allows the rotational velocity 
controller 20 to rotate the spindle motor 24 at a speed of 100 rps by 
controlling the rotational velocity controller 20 (step 48). In response 
to a rotation of the spindle motor 24 at the speed of 100 rps, the optical 
disc D also is subject to rotate at a speed of 100 rps. 
On the other hand, if it is decided that the normal video data NVD is 
applied to the input/output line 11 in step 44, then the microcomputer 16 
allows the clock generator 22 to generate the second clock signal SCS of 5 
MHz by controlling the clock generator 22 via the clock frequency change 
portion 18 (step 50). At this time, the formatter 26 inputs the normal 
video data NVD in the buffer 12 at a rate of 5 Mbps, by means of the 
second clock signal from the clock generator 22. As a result, the normal 
video data NVD recorded on the optical disc D is transferred at a rate of 
5 Mbps by way of the formatter 26, the DSP 28, the channel modem 30, the 
recording portion 34 and the optical pickup device 32. Subsequently, the 
microcomputer 16 allows the rotational velocity controller 20 to rotate 
the spindle motor 24 at a speed of 50 rps by controlling the rotational 
velocity controller 20 (step 52). In response to a rotation of the spindle 
motor 24 at the speed of 50 rps, the optical disc D also is subject to 
rotate at a speed of 50 rps. 
After performing the above steps 46-48 or 50-52, the microcomputer 16 
controls the optical pickup device 32 by allowing the optical pickup 
device 32 to record the data bit stream from the channel modem 30 on the 
optical disc D (step 54). As a result, an appropriate frame data pit 
train, such as HVDP or NVDP in FIG. 4, is generated in the optical disc D. 
Herein, HVDP represents a data pit train relative to one frame of high 
resolution video data, and NVDP represents a data pit train relative to 
one frame of normal video data. 
FIG. 7 is a flow chart for explaining a multi-rate recording method 
according to the second embodiment of the present invention. The process 
in FIG. 7 is performed by the microcomputer 16 (shown in FIG. 3). 
Referring now to FIG. 7, in step 56, the microcomputer 16 waits until a 
record instruction is inputted from the key input portion 14. If the 
record instruction is inputted in step 56, then the microcomputer 16 sets 
a record mode flag assigned in a part of register therein, and inputs a 
transfer rate value of video data from the transfer rate detector 10 (step 
58). 
In step 60, the microcomputer 16 decides, based on the transfer rate value, 
if the video data VDS on the input/output line 11 is high resolution video 
data HVD or normal video data NVD. When the transfer rate value is 10 
Mbps, the microcomputer 16 decides that the high resolution video data HVD 
is being applied to the input/output line 11. When the transfer rate value 
is 5 Mbps, the microcomputer 16 decides that the normal video data NVD is 
being applied to the input/output line 11. 
If it is decided that the high resolution video data HVD is applied to the 
input/output line 11 in step 60, then the microcomputer 16 sets the first 
recording speed mode flag assigned in a part of register therein, 
specifying that the data is to be recorded at a rate of 10 Mbps (step 62). 
On the other hand, if it is decided that the normal video data NVD is 
applied to the input/output line 11 in step 60, then the microcomputer 16 
sets the second recording speed mode flag assigned in a part of register 
therein instead of the first recording speed mode flag, specifying that 
the data is to be recorded at a rate of 5 Mbps (step 64). 
After performing the above step 62 or 64, the microcomputer 16 controls the 
spindle motor 24 via the rotational velocity controller 20 such that the 
spindle motor 24 rotates at a rate corresponding to the recording speed 
mode set in step 62 or 64. At the same time, the microcomputer 16 
retrieves a table on the lead-in area of optical disc D inputted by way of 
the optical pickup device 32, the recording portion 36, channel modem 30 
and the DSP 28, and decides whether there are a previously recorded video 
data or not (step 66). When a start address and an end address exist in 
the table, the microcomputer 16 decides that previously recorded data 
exists in the optical disc D. Otherwise, when an start address and an end 
address data do not exist in the retrieved table, the microcomputer 16 
decides that previously recorded data does not exist in the optical disc 
D. The spindle motor 24 rotates at a rate of 100 rps when the first 
recording speed mode is set in step 62 while rotating at a rate of 50 rps 
when the second recording speed mode is set in step 64. 
In step 66, if there is data recorded previously in the optical disc, then 
the microcomputer 16 compares a logical value of the recording speed mode 
flag with that of the transfer speed mode flag on the table, and decides 
whether the recording speed mode of the previously recorded data is 
identical to that of the data to be recorded (step 68). If the logical 
value of the recording speed mode flag is not identical to that of the 
transfer speed mode flag, it is judged that the recording speed mode of 
the previously recorded data is different from that of the video data to 
be recorded. 
When the recording speed mode of the previously recorded data is different 
from that of the video data to be recorded in step 68, the microcomputer 
16 allows the spindle motor 24 to be rotated at a speed corresponding to 
the recording speed mode of the previously recorded data by controlling 
the spindle motor 24 via the rotation velocity controller 20. The final 
portion of the recording region is then sought based on whether data is 
inputted from the DSP 28, making a track jump of the optical pickup device 
32 if necessary (step 70). At this time, if the first recording speed mode 
was set in step 62, the spindle motor 24 rotates at a speed of 50 rps; 
whereas if the second recording speed mode was set in step 64, the spindle 
motor 24 rotates at a speed of 100 rps. Further, the microcomputer 16 
allows the clock generator 22 to supply a clock signal to the formatter 26 
having a frequency corresponding to the recording speed mode by 
controlling the clock generator 22 via the clock frequency change portion 
18 (step 72). For example, when the first recording speed mode is set in 
step 62, the clock generator 22 applies the first clock signal FCS to the 
formatter 26. Accordingly, the high resolution video data on the 
input/output line 11 is delivered to the optical pickup device 32 at a 
transfer rate of 10 Mbps via the buffer 12, the formatter 26, the DSP 28, 
the channel modem 30 and the recording portion 34 in turn. Otherwise, when 
the second recording speed mode is set in step 64, the clock generator 22 
applies the second clock signal SCS to the formatter 26. Thus, the normal 
video data NVD on the input/output line 11 is transferred at a transfer 
rate of 5 Mbps via the buffer 12, the formatter 26, the DSP 28, the 
channel modem 30 and the recording portion 34 in turn into the optical 
pickup device 32. The microcomputer 16 allows the spindle motor 24 to 
rotate at a speed corresponding to the recording speed mode set in step 62 
or 64 by controlling the spindle motor 24 via the rotation velocity 
controller 20 (step 74), and then it waits until the rotation speed of the 
spindle motor 24 maintains a speed corresponding to the recording speed 
mode set in step 62 or 64 stabbly (step 76). 
On the other hand, if the recording speed mode of the previously recorded 
data is identical to that of the video data to be recorded in step 68, 
then the microcomputer 16 seeks the final portion of the previously 
recorded region based on whether data is inputted from the DSP 28, making 
a track jump of the optical pickup device 32 if necessary (step 78). 
Further, the microcomputer 16 allows the clock generator 22 to supply a 
clock signal having a frequency corresponding to the recording speed mode 
with the formatter 26 (step 80). 
Moreover, if the optical disc D does not appear to contain previously 
recorded data in step 66, then the microcomputer 16 allows the clock 
generator 22 to supply a clock signal having a frequency corresponding to 
the recording speed mode to formatter 26 by controlling the clock 
generator 22 via the clock frequency change portion 18 (step 118). 
After performing the above step 76, 80 or 118, the microcomputer 16 allows 
the optical pickup device 32 to irradiate a relatively large energy of 
light beam switched under control of the recording portion 34 on the 
surface of the optical disc D by controlling the optical pickup device 32, 
such that the video data VDS is recorded on the optical disc D (step 84). 
FIG. 8 explains a recorded state of the high resolution video data HVD in 
the first recording speed mode and the normal video data NVD in the second 
recording speed mode, when those video data are recorded on the optical 
disc D by the second embodiment of the present invention. In FIG. 8, a 
speed DSV of the spindle motor 22 remains at 100 rps until first time t1, 
at which time the final portion of the high resolution video data HVD in 
the first recording speed mode recorded on the optical disc D is 
retrieved. At time E1, the optical pickup device 32 is disposed on the 
first position p1, which is the final portion of the high resolution video 
data in the first recording speed mode. 
Beginning at the first time t1, the rotation speed of the spindle motor 22 
decreases slowly until a speed of 50 rps is achieved at second time t2. At 
the second time t2, the optical pickup device 32 moves from the first 
position p1, which is the final portion of the high resolution video data 
in the first recording speed mode, to the second position p2 spaced by a 
certain distance s.sub.e from the first position p1. The optical pickup 
device 32 records the normal video data NVD in the second recording speed 
mode from the second position p2 on the track. Thus, a non-recorded region 
having a length equal to the movement distance s.sub.e occurs during a 
rotation speed stabilization period t1-t2 of the spindle motor 22 between 
the high resolution video data HVD in the first recording speed mode and 
the normal video data NVD in the second recording speed mode. 
FIG. 9 is a flow chart for explaining a multi-rate recording method 
according to the third embodiment of the present invention. The process in 
FIG. 9 is performed by the microcomputer 16 (shown in FIG. 3). 
Referring now to FIG. 9, in step 86, the microcomputer 16 waits until a 
record instruction is inputted from the key input portion 14. If the 
record instruction is inputted in step 86, then the microcomputer 16 sets 
a record mode flag assigned in a part of register therein, and inputs a 
transfer rate value of video data from the transfer rate detector 10 (step 
88). 
In step 90, the microcomputer 16 decides based on the transfer rate value 
whether the video data VDS on the input/output line 11 corresponds to high 
resolution video data HVD or normal video data NVD. When the transfer rate 
value is 10 Mbps, the microcomputer 16 decides that the high resolution 
video data HVD is being applied to the input/output line 11. When the 
transfer rate value is 5 Mbps, the microcomputer 16 decides that the 
normal video data NVD is being applied to the input/output line 11. If it 
is decided that the high resolution video data HVD is applied to the 
input/output line 11 in step 90, then the microcomputer 16 sets the first 
recording speed mode flag assigned in a part of register therein, 
specifying that the data is to be recorded at a rate of 10 Mbps (step 92). 
On the other hand, if it is decided that the normal video data NVD is 
applied to the input/output line 11 in step 90, then the microcomputer 16 
sets the second recording speed mode flag assigned in a part of register 
therein instead of the first recording speed mode flag, specifying that 
the data is to be recorded at a rate of 5 Mbps (step 94). 
After performing the above step 92 or 94, the microcomputer 16 controls the 
spindle motor 24 via the rotational velocity controller 20 such that the 
spindle motor 24 rotates at a rate corresponding to the recording speed 
mode set in step 92 or 94. At the same time, the microcomputer 16 
retrieves a table on the lead-in area of optical disc D inputted by way of 
the optical pickup device 32, the recording portion 36, channel modem 30 
and the DSP 28, and decides whether there exists previously recorded data 
or not (step 96). When a start address and an end address exist in the 
table, the microcomputer 16 decides that the data recorded previously 
exists in the optical disc D. Otherwise, when an start address and an end 
address do not exist in the table, the microcomputer 16 decides that 
previously recorded data does not exist in the optical disc D. The spindle 
motor 24 rotates at a rate of 100 rps when the first recording speed mode 
is set in step 92 while rotating at a rate of 50 rps when the second 
recording speed mode is set in step 94. 
In step 96, if there is data recorded previously in the optical disc, then 
the microcomputer 16 compares a logical value of the recording speed mode 
flag with that of the transfer speed mode flag on the table, and decides 
whether the recording speed mode of the previously recorded data is 
identical to that of the data to be recorded (step 98). If the logical 
value of the transfer speed mode flag is not identical to that of the 
recording speed mode flag, it is judged that the recording speed mode of 
the previously recorded data is different from that of the video data to 
be recorded. 
When the recording speed mode of the previously recorded data is different 
from that of the video data to be recorded in step 98, the microcomputer 
16 allows the spindle motor 24 to be rotated at a speed corresponding to 
the recording speed mode of the previously recorded data by controlling 
the spindle motor 24 via the rotation velocity controller 20. The final 
portion of the recording region is then sought based on whether data is 
inputted from the DSP 28, with making a track jump of the optical pickup 
device 32 if necessary (step 100). At this time, if the first recording 
speed mode was set in step 92, the spindle motor 24 rotates at a speed of 
50 rps; whereas if the second recording speed mode was set in step 94, the 
spindle motor 24 rotates at a speed of 100 rps. Further, the microcomputer 
16 inputs an address relative to the final portion of the previously 
recorded region from the DSP 28 (step 102), and thereafter allows the 
clock generator 22 to supply a clock signal having a frequency 
corresponding to the recording speed mode with the formatter 26 by 
controlling the clock generator 22 via the clock frequency change portion 
18 (step 104). For example, when the first recording speed mode is set in 
step 92, the clock generator 22 applies the first clock signal FCS to the 
formatter 26. Accordingly, the high resolution video data on the 
input/output line 11 is delivered to the optical pickup device 32 at a 
transfer rate of 10 Mbps via the buffer 12, the formatter 26, the DSP 28, 
the channel modem 30 and the recording portion 34. Otherwise, when the 
second recording speed mode is set in step 94, the clock generator 22 
applies the second clock signal SCS to the formatter 26. Thus, the normal 
video data NVD on the input/output line 11 is transferred into the optical 
pickup device 32 at a transfer rate of 5 Mbps via the buffer 12, the 
formatter 26, the DSP 28, the channel modem 30 and the recording portion 
34. The microcomputer 16 allows the spindle motor 24 to rotate at a speed 
corresponding to the recording speed mode set in step 92 or 94 by 
controlling the spindle motor 24 via the rotation velocity controller 20 
(step 106), and then it waits until the rotation speed of the spindle 
motor 24 maintains a speed corresponding to the recording speed mode set 
in step 92 or 94 stabbly (step 108). 
In step 108, when the rotation speed of the spindle motor 24 arrives at a 
speed corresponding to the recording speed mode set in step 92 or 94, the 
microcomputer 16 moves the optical pickup device 32 into the previous 
track of the optical disc D (step 110). Next, the microcomputer 16 waits 
until an address relative to the final portion of the recording region 
from the DSP 28 (step 112). 
On the other hand, if the recording speed mode of the previously recorded 
data is identical to that of the video data to be recorded in step 98, 
then the microcomputer 16 seeks the final portion of the previously 
recorded region based on whether data is inputted from the DSP 28, making 
a track jump of the optical pickup device 32 if necessary (step 114). 
Further, the microcomputer 16 allows the clock generator 22 to supply a 
clock signal having a frequency corresponding to the recording speed mode 
with the formatter 26 (step 116). 
Moreover, if the optical disc D does not appear to contain previously 
recorded data in step 96, then the microcomputer 16 allows the clock 
generator 22 to supply a clock signal having a frequency corresponding to 
the recording speed mode to formatter 26 by controlling the clock 
generator 22 via the clock frequency change portion 18 (step 118). 
After performing the above step 112, 116 or 118, the microcomputer 16 
allows the optical pickup device 32 to irradiate a relatively large energy 
of light beam, switched under control of the recording portion 34, on the 
surface of the optical disc D by controlling the optical pickup device 32. 
As such, the video data VDS is recorded on the optical disc D (step 120). 
FIG. 10 explains a recorded state of the high resolution video data HVD in 
the first recording speed mode and the normal video data NVD in the second 
recording speed mode, when those video data are recorded on the optical 
disc D by the third embodiment of the present invention. In FIG. 10, a 
speed DSV of the spindle motor 22 remains at 100 rps until first time t1, 
at which time the final portion of the high resolution video data HVD in 
the first recording speed mode recorded on the optical disc D is 
retrieved. At time t1, the optical pickup device 32 is disposed on the 
first position p1, which is the final portion of the high resolution video 
data in the first recording speed mode. 
Beginning at the first time t1, the rotation speed DSV of the spindle motor 
22 decreases slowly until a speed of 50 rps is achieved at second time t2. 
At the second time t2, the optical pickup device 32 moves from the first 
position p1, which is the final portion of the high resolution video data 
in the first recording speed mode, to the second position p2 spaced by a 
certain distance s.sub.e from the first position p1. 
The optical pickup device 32 makes a track jump by a certain distance 
s.sub.b from the second position p2 on the track to be positioned the 
third position p3 preceding the first position p1. Further, the optical 
pickup device 32 records the normal video data NVD in the second recording 
speed mode from the third time t3 arrived at the high resolution video 
data HVD in the first recording speed mode on the track of the optical 
disc D. Thus, the normal video data NVD in the second recording speed mode 
is recorded from the final portion of the high resolution video data HVD 
in the second recording speed mode such that non-recorded region is not 
generated. 
As described above, according to a multi-rate recording method and 
apparatus of the present invention, the rotation velocity of the optical 
disc and the processing speed of data can be controlled in accordance with 
the transfer rate of the data to be recorded such that the unnecessary 
data is not recorded on the optical disc. As a result, the multi-rate 
recording method and apparatus according to the present invention provides 
an advantage in that it can improve recording efficiency of optical disc 
and the recording time thereof dramatically. 
Although the present invention has been described by the preferred 
embodiments illustrated in drawings hereinbefore, it is apparent from the 
above description to those ordinarily skilled in the art that various 
changes and modifications of the invention are possible without departing 
from the spirit thereof. For instance, it may be suggested that the buffer 
shown in FIG. 3 is disposed between the formatter 26 and the DSP 28 or 
between the DSP 28 or the channel modem 30 to supply the clock signal 
generated at the clock generator 22 with the DSP 28 or the channel modem 
30, thereby controlling the processing speed of video data. Also, while 
the present invention has been described to be limited to the video data, 
it is to be understood that it may be applied to other data such as text 
data and packet data, etc. Accordingly, the scope of the invention should 
be determined not by the embodiments illustrated and described, but by the 
appended claims and their equivalents.