JPH0879710A - Disk data reproducing method and reproducing device - Google Patents

Abstract

PURPOSE: To quickly perform special reproduction in a disk data reproducing device. CONSTITUTION: At the time of special reproduction of reverse direction I picture, I pictures stored in an IP buffer 9 are outputted from the IP buffer 9 reversely. During the time of the output, an operation for accessing of a disk to a FIFO buffer 10 and writing only the read I pictures is performed. When the read of data of the IP buffer 9 is ended, changeover to the output from the FIFO buffer 10 is performed and the data of the following I pictures are outputted. The read of the IP buffer and the write/read of the FIFO buffer 10 are controlled by a controller 11. Thus, quick special reproduction is made possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc data reproducing method and a disc data reproducing apparatus suitable for reproducing data such as video or audio recorded on an optical disc or a magneto-optical disc.

[0002]

2. Description of the Related Art MPEG (Motion Pic) is a method for compressing and encoding a digital image signal recorded on a conventional digital video disk (hereinafter referred to as DVD).
ture coding Experts Group) method has been proposed,
An example of an MPEG encoder will be described with reference to FIG. The MPEG encoder is an encoder that performs compression by predictive encoding, and the digitized image input signal is divided into blocks in the motion detection circuit 101 for each minimum unit block (MB) of motion compensation prediction. Then, motion vector detection for motion compensation prediction is performed for each block.

This block is predictively coded in the subsequent predictive coding unit. (1) The DCT is directly applied to the image input signal.
(Discrete Cosine Transform): Intra block that performs (discrete cosine transform), (2) forward block that predicts only from the forward direction, (3) backward block that predicts only from the backward direction, and (4) bi-predictive block that predicts from both directions. Classified into one.

In the DCT 103 of this predictive coding unit, DCT which is a kind of Fourier transform is performed, and the resulting DCT coefficient is quantized in the quantization circuit 104. Further, after being quantized, the variable length coding means 109 assigns codes of different lengths according to the occurrence probabilities to perform variable length coding. Also,
The quantized signal is inversely quantized in the inverse quantization circuit 105, further inverse DCT is performed in the inverse DCT 106, and the output from the frame memory predictor 108 is added to reproduce the original image signal. It The reproduced image signal is supplied to the subtractor 102 as a prediction signal.

The predictive coded signal output from the variable length coding means 109 is multiplexed with the prediction mode information and motion vector information in the multiplexing means 110, and these multiplexed data are at irregular rates. Therefore, it is temporarily stored in the buffer 111 and is output with a constant coding rate. In addition, in order to keep the average of the coding rates constant, the quantization scale factor q of the quantizing means 104 depends on the code amount accumulated in the buffer 111.
The code amount may be controlled by changing the.

[0006] MPEG predictively coded in this way
The structure of the inter-frame prediction of is shown in FIG. In this figure, one GOP (Group Of Picture) is composed of, for example, nine frames, and one I picture is included in one GOP.
A frame, two P pictures, and six B pictures are included. GOP is a unit of coding that is obtained by dividing one sequence of a moving image. The I picture is a predictive coded image within a frame, and the P picture is an interframe predictive coded image that is predicted by referring to an already coded temporally previous frame (I picture or P picture). A B picture is an interframe predictive coded image that is predicted by referring to two frames temporally preceding and following.

That is, the I picture I ₀ is predictively coded only within the frame, and as shown by the arrow, the P picture P ₀ is interframe predictive coded with reference to the I picture I _0. , P picture P ₁ is interframe predictive coded with reference to P picture P ₀ . Further, the B pictures B ₀ and B ₁ are interframe predictive coded with reference to two I pictures I ₀ and P pictures P ₀ , and the B pictures B ₂ and B ₃ are P pictures P ₀ and P _0. Inter-frame predictive coding is performed with reference to two of the pictures P ₁ . Similarly, predictive coding and subsequent pictures are coded.

By the way, in order to decode a picture that is predictively coded in this way, since an I picture is predictively coded within a frame, it is possible to decode only an I picture, but a P picture. Is predictively coded with reference to a temporally previous I picture or P picture, a temporally previous I picture or P picture is required at the time of decoding, and a B picture is a temporally preceding or subsequent I picture. Alternatively, since it is predictively coded with reference to a P picture, it is an I picture or a P picture that is temporally preceding and following.
The picture is needed at decoding. Therefore, as shown in FIG. 9, the picture required for decoding can be decoded first.
Pictures are exchanged as shown in (b).

[0009] As shown in this replacement FIG, B-pictures B _-1, since B _-2 is in need of I-picture I ₀ upon decoding, B-pictures B _-1, I picture I ₀ from B _-2 prior Therefore, the B pictures B ₀ and B ₁ are I pictures I at the time of decoding.
B picture B because ₀ and P picture P ₀ are required
Similarly, the P picture P ₀ precedes ₀ and B ₁ , so that B
Since the pictures B ₂ and B ₃ require the P picture P ₀ and the P picture P ₁ at the time of decoding, the pictures B ₂ and B ₃ are exchanged so that the P picture P ₁ precedes the B pictures B ₂ and B ₃ .

The I-picture, P-picture and B-picture are recorded on the DVD in the order shown in FIG. 9B. Since these pictures are predictively coded as described above, their codes are The amount is not constant for each picture, but varies depending on the complexity of the image, the flatness, and the like. Therefore, when these pictures are recorded on the DVD, they are recorded using sectors defined by a fixed code amount. FIG. 1 shows a mode of recording by this sector.
For example, the I picture I ₀ is recorded in the sector m, the sector (m + 1) and a partial area of the sector (m + 2), and the B picture B ₋₂ is recorded in the remaining area of the sector (m + 2) and the sector (m + 3). Recorded in. Hereinafter, each picture is sequentially recorded in the sector, and in this example, 1 GOP is recorded in the sector m to sector (m + 13). However, the GOP is not always recorded with such a number of sectors, and the code amount is different depending on the complexity and flatness of the image, so that the number of recorded sectors is also generally different for each image.

Next, FIG. 11 shows an example of the structure of a disk data reproducing apparatus for reproducing an image from a disk which is compressed and recorded by the MPEG system as described above. In this figure, a disc 1 such as an optical disc is rotationally controlled by a spindle motor (not shown) so as to rotate at a predetermined number of revolutions, and a track of the disc 1 is irradiated with laser light from a pickup 2 to record on the track. The compression-encoded digital data being read is read. This digital data is demodulated by the demodulation circuit 3 and input to the sector detection circuit 6. The output of pickup 2 is the phase locked loop (PL
L) The clock is regenerated by being input to the circuit 4. This reproduction clock is supplied to the demodulation circuit 3 and the sector detection circuit 6.

Although the digital data recorded on the disk 1 is recorded in units of fixed length sectors shown in FIG. 10, the sector sync and sector address are added to the beginning of each sector. Therefore, the sector detection circuit 6 detects the sector sync to detect the sector delimiter, and also detects the sector address indicating the position of the physical sector.
1 is supplied. Further, the demodulated output is input to the ECC (error correction) circuit 7 via the sector detection circuit 6 and error detection / correction is performed. Data that has been error corrected is EC
The data is supplied from the C circuit 7 to the FIFO buffer 10, and the control device 1
According to the control of 1, data is written while being managed in units of sectors.

The focus control and the tracking control of the pickup 2 are performed by a tracking servo circuit according to the control of the system control by the focus error signal and the tracking error signal obtained from the information read from the pickup 2.
It is performed by the focus servo circuit. Here, based on the sector address of each sector detected by the sector detection circuit 6, the control device 11 sets the write address for writing the sector to the FIFO buffer 10 to the write pointer W.D.
Specify with P. Further, the control device 11 uses the FIFO buffer 1
The read address of the data written in the read pointer R.0. Specify with P. Then, the read pointer R. P
The data is read from the position of and is supplied to the sector / MPEG stream conversion circuit 13.

Sector / MPEG stream conversion circuit 13
The sector data supplied to is converted into MPEG stream data and the subsequent video decoding circuit (decoder)
14 and is decoded. As a result, the decoded data is arranged in the order shown in FIG. 9B. However, since the images are interchanged as it is, they are rearranged to have the original frame order shown in FIG. 9A. It is output to a digital / analog (D / A) converter. This data is converted into an analog video signal and displayed on the display 1.
Displayed at 6.

By the way, the control device 11 responds to the request signal from the video decoding circuit 14 which is output when the decoding is completed. The data set in P and stored in the FIFO buffer 10 is supplied to the video decoding circuit 14 via the sector / MPEG stream conversion circuit 13, but the MPEG stream information has a variable length as described above. In order to display an image on the display 16 at a constant cycle, the data sent to the video decoding circuit 14 must be transferred non-uniformly.
Therefore, the sector data written to the FIFO buffer 10 needs to be written at a faster interval than the output sector data. That is, since the amount of data written to the FIFO buffer 10 must be larger than the amount of data output to the video decoding circuit 14, the FIFO buffer 10 may overflow.

For this reason, the write pointer W. P and read pointer R.P. The amount of data currently stored in the FIFO buffer 10 is calculated from the address position of P, and when the amount of data exceeds a preset reference value, it is determined that the FIFO buffer 10 may overflow. Thus, the controller 11 outputs a track jump command to the tracking servo circuit 5.

When the track jump command is output, the tracking servo circuit 5 performs the track jump of the reproduction position in the pickup 2. That is, when the data is recorded from the inner circumference to the outer circumference, the pickup 2 for several tracks from the current position of the disc 1 to the inner circumference side.
To the FIFO buffer 10 for new data until the reproduction position by the pickup 2 reaches the position before the jump, that is, until the sector number obtained from the sector detection circuit 6 becomes the sector number at the time of track jump. Writing is stopped. Meanwhile, if necessary, the read pointer R. The data designated by P is read out and transferred to the video decoding circuit 14.

After the track jump, even if the sector number obtained from the sector detection circuit 4 matches the sector number before the jump, if the remaining amount of data in the FIFO buffer 10 exceeds the predetermined reference value, the FIFO buffer 10 The writing of data to is not resumed, and a track jump is performed again to prevent overflow. Therefore, in order to send the data to be sent to the video decoding circuit 14 without interruption, the FIFO buffer 10 needs to perform at least the time from when the track jump is performed until the address immediately before the track jump is returned to again. When the amount of data to be sent to 14, that is, the one-track reverse jump, it is necessary to have an area for holding at least the amount of data corresponding to the time for one track.

The data transfer rate from the FIFO buffer 10 to the video decoding circuit 14 is set equal to or smaller than the data transfer rate written in the FIFO buffer 10. By doing so, the data transfer from the video decoding circuit 14 to the FIFO buffer 10 is performed regardless of the timing of the track jump.
It will be possible to send freely. Like this FI
By controlling the FO buffer 10, data transfer to the video decoding circuit 14 can be continuously sent without interruption, so that a uniform image quality can be obtained regardless of the complexity or flatness of the image recorded on the disc 1. The video can be played continuously.

[0020]

Considering thinning out only P pictures and B pictures or only B pictures of a moving picture sequence and performing special reproduction in the forward direction, for example, as shown in FIG. 3 (1), I ₀ , I ₁ , I ₂ , I
₃ , I ₄ , I ₅ , I ₆ , I ₇ , I ₈ , I, ... Forward I-picture special reproduction in order, or FIG.
As shown in (3), I ₀ , P ₀ , I ₁ , P ₁ , I ₂ ,
In order to perform forward I / P picture special reproduction in which P ₂ , I ₃ , P ₃ , I ₄ , ...
M that includes video information that is located in the rear (future) on the time axis at 0
Since the PEG stream is stored in the area that has not been read yet, I
By sending the picture and P picture information, the forward special playback can be performed quickly.

However, in the disc data reproducing apparatus shown in FIG. 11, the reverse direction I shown in FIG.
Picture trick play and backward I / O shown in FIG.
The P-picture trick play has a problem that the backward trick play cannot be performed quickly. That is, I ₈ , I
₇ , I ₆ , I ₅ , I ₄ , I ₃ , I ₂ , I ₁ , I ₀ , ...
.., when the pictures are reproduced in this order, and I ₄ ,
P ₃ , I ₃ , P ₂ , I ₂ , P ₁ , I ₁ , P ₀ , I ₀ , ...
When reproducing in the order of ..., the data already sent to the video decoding circuit 14 is still in the FIFO buffer 10.
Read pointer R. Although P may be returned to the original state and the data may be sent to the video decoding circuit 14 again, generally, the storage capacity of the FIFO buffer 10 is not so large.

Therefore, in order to send data to the video decoding circuit 14, the pickup 2 is track-jumped in the inner peripheral direction to move to a predetermined sector address for access, and the read sector data is written to the FIFO buffer 10. Need to In addition, since the P picture needs to be decoded by referring to the I picture or P picture that is temporally preceding as described above,
The picture to be referred to must also be accessed by reading the disk 1 and frequently accessed.

As described above, when the data is sent to the video decoding circuit 14, a delay in the moving time of the pickup 2 is included, so that the backward special reproduction cannot be performed quickly. Further, even if the read data remains in the FIFO buffer 10, it is necessary to read the picture to be referred to during decoding. P must be moved at indefinite intervals, and the read pointer R.P. P and write pointer W.P. There is a problem that the control of P becomes complicated.

Therefore, it is an object of the present invention to provide a disc data reproducing method and a disc data reproducing device which can perform special reproduction rapidly without frequently accessing the disc.

[0025]

In order to achieve the above object, a disk data reproducing method according to the present invention is such that data read from a disk is demodulated and written in a storage means, and data read from the storage means is read. In the disc data reproducing method of reproducing original data by decoding, attribute information indicating an attribute of the data is added to the data, and the attribute information of the data read from the storage means is: When it has a predetermined specific attribute, the data is stored in the second storage means.

In the disc data reproducing method, the storage area of the storage means divides a GOP unit of an MPEG stream, a sector unit obtained by dividing a GOP by a fixed amount, or a picture forming a GOP by a fixed amount. It is managed in sector units,
Further, a detection means for detecting sector information from the demodulated data is provided, and writing / reading of the storage means is controlled by utilizing the sector information detected by the detection means. Further, when the reverse reproduction mode is set, the data stored in the second storage means is read and decoded.

The disc data reproducing apparatus of the present invention for realizing the disc data reproducing method of the present invention includes a demodulation circuit for demodulating the data read from the disc, a control for writing the demodulated data in the storage means, and In a disc data reproducing device including a control device for controlling reading of data from a storage device and a decoding circuit for reproducing the data read from the storage device to original data, the data added to the data A detection means for detecting information indicating an attribute, wherein when the attribute information of the data read from the storage means has a predetermined specific attribute, the data is stored in the second storage means Is.

In the disc data reproducing apparatus, the storage area of the storage means is a GOP unit of an MPEG stream, a sector unit obtained by dividing a GOP by a fixed amount, or a sector obtained by dividing a picture forming a GOP by a fixed amount. Each unit is managed by the control device, and a detection circuit for detecting sector information from the data output from the demodulation circuit is provided, and the control circuit is detected by the detection circuit. The writing / reading of the storage means is controlled by using the sector information. Furthermore, when it is set to reverse playback mode,
The data stored in the second storage means is read out and supplied to the decoding circuit.

[0029]

According to the present invention, according to the attribute information of the data,
Since the data read from the storage means to be supplied to the decoding means is stored in the second storage means, it is possible to hold a certain amount of, for example, I picture or P picture even after the data is decoded. In the special reproduction mode, necessary data can be read from the second storage means to be decoded and displayed. This eliminates the need to repeatedly read the data required for decoding from the disc each time an image is played back one by one during special playback, and the waiting time required for reading from the disc can be shortened, resulting in a smooth and quick operation. Special playback can be realized.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of an embodiment of a disc data reproducing apparatus for realizing the disc data reproducing method of the present invention.
In this figure, 1 is a disc on which video signals such as moving images and audio signals are compressed and encoded by the MPEG system and recorded, 2 is a pickup for irradiating the disc 1 with laser light to read the recorded data, Reference numeral 3 is a demodulation circuit for demodulating data read by the pickup, and 4 is a phase locked loop for reproducing a clock from the data read from the pickup 2 and supplying a reproduction clock to the demodulation circuit 3 and the sector detection circuit 6. (PLL) circuit,
Reference numeral 5 denotes a tracking control circuit for the pickup 2 and a tracking servo circuit for controlling the pickup 2 to jump to a predetermined track.

A sector detection circuit 6 detects the sector address of the sector data output from the demodulation circuit 3 and supplies the information to the control device 11, and a reference numeral 7 detects and corrects an error in the input data. An error correction (ECC) circuit 8 detects the sector header of the data output from the ECC circuit 7, the attribute information of the data such as the type of stream information and the type of the picture, and outputs the sector header information and the attribute information to the control device 11. Stream information detection circuit to be supplied to 9
Is an IP buffer which is a second storage means in which the data of the I picture read from the FIFO buffer 10 or the data of the I picture and the P picture is written, and 10 is the data output from the stream information detection circuit 8 in units of sectors. It is a FIFO buffer that is a storage means to be written.

Further, 11 controls writing of data to the FIFO buffer 10 and controls reading of data from the FIFO buffer 10 based on the supplied sector address when a request signal is applied, and
The control device controls writing / reading of data to / from the IP buffer 9. Further, the control device 11 controls the write pointer W. P and read pointer R.P. It is determined whether or not the pickup 2 should be track-jumped from the position of P. If it is determined that the pickup 2 should be track-jumped, a track jump command is issued to the tracking servo circuit 5 so that the pickup 2 is also track-jumped. .

Furthermore, 12 is normal reproduction, variable speed reproduction,
A user interface for instructing the control circuit 6 to perform reverse reproduction and the like, 13 is a sector / MPEG for converting sector data into MPEG stream information and outputting it to the video decoding circuit 14.
A stream conversion circuit, a video decoding circuit (decoder) 14 for returning compressed data that has been MPEG-encoded to the original data and sending a request signal to the control device 11 to request input of new data, and 15 for decoding the decoded data into analog data. Is a digital / analog converter (D / A), which is converted to a video signal and sent to the display 16, is a display on which the decoded reproduced video is displayed.

Since the operation of the disc data reproducing apparatus constructed as described above is almost the same as the operation of the construction shown in FIG. 11, the stream information detecting circuit 8, the IP buffer 9 and the user interface 12 shown in FIG. The operation based on the configuration different from that shown will be mainly described. The data output from the ECC circuit 7 in which the data recorded on the disk 1 is reproduced is in units of fixed-length sectors as shown in FIG. 10, and these sectors are used as units for accessing the disk 1. ing. The sector is formatted as shown in FIG. 2A, and a sector sync indicating a sector delimiter, a sector address indicating a physical sector position, and a sector indicating time information and sector type. It is composed of a header and main data including video data and audio data.

The sector sync and the sector address are detected by the sector detection circuit 6 to detect the head position of the sector, and the detected sector address information is supplied to the control device 11. The sector header information and the stream information are detected by the stream information detection circuit 8 and supplied to the control device 11.

The stream information detection circuit 8 analyzes the sector header and main data for each sector. For example, the main data is constructed as shown in FIG. In other words, the main data uses the start code and the type of stream (video data or audio data)
Or the type of picture that is video data (I, P, B)
, And indicates the picture type of the data following by the ID code of several bytes following the start code. For example, if the ID is “01”, the following data is an I picture, and if the ID is “02”, the following data is a P picture.
When the ID is "03", it indicates that the following data is a B picture. In this case, the start code has a pattern that never appears anywhere else in the main data. In this way, the attribute information of the data is added to the delimiter of the main data.

Therefore, in the case of a video signal, the stream information detection circuit 8 detects the start code to detect a picture break, and the subsequent ID code is analyzed to detect the picture type. Further, the stream information of the main data detected by the stream information detection circuit 8 is supplied to the control device 11, and the control device 11 includes the attribute information indicating the type of the picture of the supplied main data and the main data thereof. The sector pointers are stored as a table in a one-to-one correspondence. The table stored in the control device 11 is a read pointer R. It is used for P control and the like. On the other hand, the reproduced data output from the ECC circuit 7 is written in the FIFO buffer 10, but the read pointer R. P and write pointer W.P. P is managed.

Next, the operation when the normal reproduction mode is instructed from the user interface 12 will be described with reference to FIG. FIG. 4 shows the FIFO buffer 10, the IP buffer 9 and the control device 11 extracted from the configuration shown in FIG. P
The reproduction data output from the ECC circuit 7 is written in the position of the FIFO buffer 10 indicated by 11-1 and the read pointer R. The sector data is read from the position of the FIFO buffer 10 shown by P11-2. FIFO buffer 1
Although only I pictures are shown in 0, P pictures and I pictures are stored between I pictures in the order of FIG. 9B.

Although only I pictures are stored in the IP buffer 9 from the bottom in the order of I ₀ , I ₁ , I ₂ , I _3, ...
Based on the attribute information stored in the control device 11, the write pointer W.D. It is performed by controlling P11-2. The sector data read from the FIFO buffer 10 is decoded in the video decoding circuit 14 via the sector / MPEG stream conversion circuit 13 and displayed on the display 16 in the original video order shown in FIG. 9A. .

Referring now to the control flow chart shown in FIG. 7, the operation when the control device 11 receives an instruction for backward I-picture special reproduction in the reproduction order shown in FIG. 3B from the user interface 12 is also referred to. While explaining. When the control device 11 receives the backward I-picture special playback instruction, the backward I-picture special playback is started in step S10 of the flowchart. That is, first FI
FO buffer 10 Clears sector data stored in the buffer. Then, in step S20, the output of the FIFO buffer 10 is switched to the output of the IP buffer 9 to the video decoding circuit 14, and the stored I picture data is stored in the order of I ₃ , I ₂ , I ₁ , and I ₀ . Will be output. In this case, data writing to the IP buffer 9 is prohibited. These controls are performed by the control device 11 by the IP buffer 9
Read pointer R. This is performed by controlling P11-4 as shown in FIG.

Further, while the data is being read from the IP buffer 9, the write pointer W. By controlling P11-1, only the sector data including the I picture before the I picture finally output by the IP buffer 9 is written in the FIFO buffer 10 in the reverse order as shown in FIG. The detection of the picture is performed in the stream information detection circuit 8, and the controller 11 receives the detected attribute information and receives the write pointer W.D. By controlling P11-1
Only the I picture is written in the FIFO buffer 10. As a result, I ₋₁ , I are stored in the FIFO buffer 10.
I pictures are written in the order of _-2 , I _-3 ... In this case, the data output from the FIFO buffer 10 is stopped.

Next, in step S30, the IP buffer 9
Is determined to be empty, and if it is determined to be empty, the process proceeds to step S40, and it is determined that the output of the I-picture data from the IP buffer 9 is completed, and the control device 11 controls the IP buffer as shown in FIG. The data output from 9 is stopped, and the output is switched again to start the output of the sector data of the I picture from the FIFO buffer 10. At this time, the control device 11 causes the read pointer R. By controlling P11-2, I picture data from the FIFO buffer 10
_-1 , I _-2 , I _-3, ... Are read in this order and sent to the video decoding circuit 14, and the write pointer W. P11-1
Is controlled to write the sector data of the I picture following the FIFO buffer 10. When writing sector data to the FIFO buffer 10, the pickup 2 is moved to access the disk 1, and the sector data of the I picture read from the disk 1 is written.

As described above, the backward I-picture special reproduction is performed using the IP buffer 9, but at the start of the reproduction, the data is supplied from the IP buffer 9 to the video decoding circuit 14 and the reading of the data from the IP buffer 9 is completed. When I
Disk 1 while outputting data from P buffer 9
Is accessed and the sector data of the I picture written in the FIFO buffer 10 is subsequently output to the video decoding circuit 14. Therefore, smooth and quick backward I-picture special reproduction can be performed, and the control of the FIFO buffer 10 does not become complicated. In addition, the storage capacity of the IP buffer 9 is changed from the IP buffer 9 to the I
The FIFO buffer 10 has a capacity that does not cause an overflow during output of picture data. That is, the storage capacity of the IP buffer 9 is smaller than the storage capacity of the FIFO buffer 10.

In the above description, only the backward I-picture special reproduction is described, but during the backward I / P picture special reproduction, the I read from the FIFO buffer 10 to the IP buffer 9 is used.
The backward I / P picture special reproduction can be performed by writing the data of the picture and the P picture and writing the data of the I picture and the P picture read from the disk 1 into the FIFO buffer 10 at the time of reproduction.

In the backward I-picture special reproduction, I
Data is output from the P buffer 9 in the order of I ₃ , I ₂ , I ₁ , and I ₀ , and I ₋₂ , I ₋₄ , I _−6.
.. By writing data every other and outputting the data, backward I-picture special reproduction can be performed at two speeds. That is, during backward I-picture trick play, slow backward fast forward and fast backward fast forward after a while, improving usability.
Such two-stage speed reproduction can also be applied to reverse I / P picture special reproduction. In this case, I
Since the picture and the P picture are displayed, the reproduction speed becomes slower. The disc 1 may be an optical disc or a magneto-optical disc.

[0046]

Since the present invention is configured as described above, the data read from the FIFO buffer which is the storage means is stored in the IP buffer which is the second storage means according to the attribute information of the data. Even after decoding the data, a certain amount of specific data such as I picture or P picture can be held, and necessary data is read from the second storage means in the special reproduction mode to be decoded and displayed. You will be able to. Further, since the pickup can be moved to access the disk and the required data can be stored in the FIFO buffer 10 during the time during which the data is output from the IP buffer, the output can be output from the IP buffer. At the time of switching to the FIFO buffer 10, the video does not pause at that scene for access.

As a result, it is not necessary to repeatedly read the data required for decoding from the disc each time an image is reproduced one by one during special reproduction, and the waiting time required for reading from the disc can be shortened. Can realize quick trick play. Also,
When the interval between the video data stored in the IP buffer and the interval between the video data stored in the FIFO buffer after the backward special playback mode is operated, the backward special playback can be performed in two stages on the time axis. Playback speed can be realized and usability can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a disc data reproducing apparatus of the present invention.

FIG. 2 is a diagram showing a format of a sector according to the present invention.

FIG. 3 is a diagram showing a display order of video data at the time of special reproduction of the disc data reproducing device of the present invention.

FIG. 4 is a diagram showing operations during normal reproduction of the FIFO buffer and the IP buffer according to the present invention.

FIG. 5 is a diagram showing an operation of the FIFO buffer and the IP buffer in the backward I-picture special reproduction according to the present invention.

FIG. 6 is a diagram showing an operation of the FIFO buffer and the IP buffer in the backward I-picture special reproduction according to the present invention.

FIG. 7 is a diagram showing a reverse I-picture trick play control flowchart of the present invention.

FIG. 8 is a diagram showing a configuration of an MPEG encoder that compresses and encodes a moving image.

[Fig. 9] Fig. 9 is a diagram showing an example of a moving image sequence subjected to MPEG.

FIG. 10 is a diagram for explaining a mode of recording data in units of sectors.

FIG. 11 is a diagram showing an example of a configuration of a disc data reproducing device.

[Explanation of symbols]

 1 Disc 2 Pickup 3 Demodulation Circuit 4 PLL Circuit 5 Tracking Servo Circuit 6 Sector Detection Circuit 7 ECC Circuit 8 Stream Information Detection Circuit 9 IP Buffer 10 FIFO Buffer 11 Controller 12 User Interface 13 Sector / MPEG Stream Conversion Circuit 14 Video Decoding Circuit 15 D / A conversion circuit 16 display

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H04N 5/93 7/24 H04N 5/93 Z 7/13 Z

Claims (8)

[Claims] 1. A disc data reproducing method for reproducing original data by demodulating data read from a disc and writing the demodulated data in a storage unit, and decoding the data read from the storage unit. When the attribute information indicating the attribute of the data is added and the attribute information of the data read from the storage means is a predetermined specific attribute, the data is stored in the second storage means. A disk data reproducing method characterized by storing. 2. The storage area of the storage means is MPEG
The disc data reproducing method according to claim 1, wherein the stream data is managed in GOP units of the stream, in sector units obtained by dividing the GOP by a predetermined amount, or in sector units obtained by dividing a picture forming the GOP by a constant amount. 3. A detection means for detecting sector information from the demodulated data is provided, and writing / reading of the storage means is controlled using the sector information detected by the detection means. The method for reproducing disk data according to item 1 or 2. 4. The disc data reproduction according to claim 1, wherein when the reverse reproduction mode is set, the data stored in the second storage means is read and decoded. Method. 5. A demodulation circuit for demodulating data read from a disk, a control device for controlling the writing of demodulated data in a storage unit, and a control for reading data from the storage unit, and the storage unit. A disc data reproducing device comprising a decoding circuit for reproducing the read data to the original data, comprising a detecting means for detecting information indicating an attribute of the data, which is added to the data, and is read from the storing means. A disc data reproducing apparatus characterized in that, when the attribute information of the outputted data has a predetermined specific attribute, the data is stored in the second storage means. 6. The storage area of the storage means is MPEG
The GOP unit of a stream, a sector unit obtained by dividing a GOP by a fixed amount, or a sector unit obtained by dividing a picture forming a GOP by a fixed amount is managed by the control device. Disc data playback device. 7. A detection circuit for detecting sector information from data output from the demodulation circuit, wherein the control circuit uses the sector information detected by the detection circuit to write / read the storage means. 7. The disc data reproducing device according to claim 5, wherein the disc data reproducing device is controlled. 8. The data stored in the second storage means is read out and supplied to the decoding circuit when the reverse reproduction mode is set. Disc data playback device.