FI111108B - Method for storing digital data on a storage medium and / or for reproduction from it, a storage medium and a storage device and / or a display device - Google Patents

Abstract

In conventional recording processes, the digital data are recorded continuously from the beginning to the end of the track of the recording medium at a net data rate which is fixed in each case for the entire recording. The aim of the invention is to record and/or scan data on a recording medium with optional reading and writing access. Continuous recording of digital data is replaced by burstwise recording. As a result of the burstwise recording of the data, each burst forms a cluster on the record carrier. The data are preferably recorded in CD standard recording format at a data rate of 1.411 Mbits per second. Recording and reproducing of data on a re-recordable contactlessly scannable record carrier, for example a magneto-optical disk (MOD).

Description

111108

A method for storing and / or reproducing digital data on and from a storage medium and / or storage device and / or reproducing device for digital storage data, and for recording data and / or recording media. 5 anordning

Rotary storage media such as Compact Disc (CD) or Magneto-Opti-cal-Disc (MOD), which can be scanned without touch, are suitable for storing large amounts of digital data, preferably digital audio or video data. These recording media preferably have a spiral-shaped groove. During recording or playback, the recording medium rotates such that the groove is transported at a constant web speed (the standard CD standard is 1.2 m / s) past a radially adjustable scan-storage unit or scan-repeat unit (laser). Constant Linear Velocity (CLV) takes care of the constant track speed in the storage or playback device.

In the so-called recording methods, digital data is continuously stored for the entire recording at a specific net data rate, from the beginning of the career of the recording medium to the end of the career of the recording medium. This has the disadvantage that, in order to store data on the recording line, the corresponding data must also be continuously made available for use (can be implemented with master tapes). Because this is not always possible with the high storage capacities of such storage media 20, individual storage of data is limited.

For standard audio recording to CD, the data rate is 1.4112 Mbit / s (= 16 bit (per scan value) * 44.1 kHz (standard scan frequency on CD) * 2 (for stereo)). With such a high net data rate (net data rate is the data rate used for storing, transmitting, for example, 1 second audio information, or 1 25 second image information, etc.), playback times of about 60 minutes each can be achieved per recording line. To reduce the recording time, and thus the playback time, with a constant scan rate and stereo recording, data reduction methods are known which do not store all 16 bits of the scan value at the output of the A / D converter. For example, NIC (Near Instantaneous Companding), MSC (Multiple Adaptive Spectral Audio Coding), DPCM (Adaptive Difference Pulse-Code Modulation), ADPCM, or Delta Modulation that can achieve reduced audio quality without deciding nights compared to standard CD standard recordings, which increases playback time to 35 to 4 hours per recording medium.

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It is an object of the invention to provide data storage and / or scanning on a recording medium with an optional read and write indication, to provide a storage medium suitable for recording data, and to provide a recording and / or reproducing device for recording and / or reproducing data.

The problem is solved by the features set forth in claims 1, 8 and 14. Preferred variations of the invention are set forth in the dependent claims.

In principle, until now, the conventional continuous storage of digital data is replaced by burst-based storage, whereby, with each burst, the data 10 is itself continuously stored. In burst data storage, each burst preferably forms a sector cluster on the storage medium. A data burst refers to a predetermined amount of data, e.g., one or more bits. A sector group is understood to be that part of the groove that substantially contains one da-puncture. The term 'Cluster Recording' will be used below for such group deposits.

It is irrelevant in this storage method whether the data rate of the data to be stored, in particular the audio data, is reduced by one or a variety of data reduction methods.

The 'Cluster Recording method described below can be used to implement e.g. 20 Uses of the following: 1. Data storage with optional read / write data, including various *: net data rates.

2. Longplay audio recording (> 1h) by audio data reduction method such as MSC.

25 3. Extreme Longplay speech recording (up to 84 hours).

• n

The data is preferably stored as in the standard CD recording format at a constant scanning speed of 1.2 m / s and a scanning frequency of 44.1 kHz, and thus at a standard CD data rate of 1.411 Mbit / s, so that the CLV system and hitherto standard recording and reproducing units no changes needed.

Thus, a 1.411 Mbit recording whose data has been reduced, for example, by MSC, does not contain information on a recording medium for audio recording for only one second, as in the CD standard, but for about 4 seconds.

3, 111108

Further, it is preferable that the data to be stored is provided with an error protection code such as Cross-Interleaved-Reed-Solomon-Code (CIRC), interleaved before storage, and stored by a channel code, e.g., eight to fourteen modulation (EFM) code, wherein the EFM code is used to structure the data into s 5 EFM frames. Preferably, each EFM frame contains 24 bytes of payload data.

Preferably, the slot of the recording medium is helical and preferably preformatted with unambiguous position data by the ATIP method. Thus, one-by-one indication of each data burst of the recording medium, and thus of each sector group, is obtained so that corresponding data can be e.g. erased, rewritten or read, etc. Such storage of data with an optional read and write assignment has great advantages. For example, it will only be possible to individually store audio data.

Preferably, the length of the sector group is designed to correspond to an integer multiple of the ATIP block and thus to an integer multiple of the EFM frame. The Si-15 determines the unambiguous association of the ATIP block and the EFM frame with a particular sector group, which, above all, guarantees the unambiguous addressability of the sector group.

To improve error-free recording, prior to writing sector group CL2, the previously written sector group CL1 is preferably re-read, and upon incorrect storage of sector group CL1, the incorrect sector group is marked to prevent repetition and presentation of the invalid sector group when playing the recording medium.

The invention will now be explained in more detail by way of example in the drawing.

Fig. 1 shows a block diagram for storing an audio channel in MSC-only data implemented in a storage device.

When the analog signal is filtered by a low pass filter 1 and *: * scanned by a 16-bit analog / digital converter 2, its output has 16 bits per scan pulse for further processing. The scan values are made - once arranged in blocks - by a Fourier transform in a special calculator 3. The result is 1024 spectral coefficients for each block, which could also be obtained by measuring with a standard digital spectrum analyzer. Amplitude and phase values are then adaptively encoded multiple times by MSC-coder 4, i.e., important coefficients are represented and transmitted by several bits (up to 14), less important bits by only fewer bits. Very small irrelevant coefficients are set to zero and are not moved. In this case, the 'saved bits' are added to the other important coefficients, which are then moved accordingly.

After the MSC reduction of the data, the digital data is output from the encoder 4 at 5308.7 kHz and fed to a serial-to-parallel converter 5 whose output is connected to the data input of the cache 6. When the cache read rate is 308700 Hz, the read rate is 1.4112 MHz. The conversion of the 1.4112 MHz clock clock to 308.7 kHz is handled by a 7/32 frequency divider 7.

The cache is controlled by the control unit 8, which e.g. compares the data of the current drive 10 of the storage medium 11 with the setpoint data of the station 14. Only when the cache 6 contains at least as much data as is stored in the setpoint burst set, the cache announces via the signaling line 13 is 'Data Ready'. When the storage medium has reached the set point, memory readout is activated via 'Output Control1 12' and the corresponding data burst is read from the cache at a data rate of 1.4112 Mbps according to CD Standard 15 and provided with a 9 CIRC error protection code in the Reed-Solomon codes ( Cross-Interleaved-Reed-Solomon-Code) and is interleaved (code interleaving). For interleaving, the encoder 9 is provided with an interleaving memory (not shown). The time course of digital data processing and storage is depicted in the observation image in Figure 1.

20 Since non-touch scannable recording media such as MOD may have various physical failures that cannot be reliably avoided in the production of discs, the audio signals to be recorded are encoded according to this particular encoding method L. In the Reed-Solomon encoder 9, the encoded data is eight-to-fourteen modulation modulated by modulator 10 and stored in the MOD by this line code 25, whereupon the data is structured in EFM modulation into EFM frames. This is also the format used on Compact Disc.

The storage arrangement is such that 24 bytes of payload (= 6 stereo scan values and 16 bits) are stored in the EFM frame at any given time. However, due to interleaving, these 24 bytes of the frame are not included in adjacent scan-30 values of the payload data. The data belonging to the adjacent scan values is divided into about 110 consecutive frames. This improves the prevention of errors.

In principle, the scanning or reproduction of data on the recording medium is in the opposite way to the recording.

5 111108 The Magneto-Optical-Disc (MOD) disk 11 used as a non-contactable scannable rotary suction device comprises a preformatted coil. a second groove containing data for absolute position recognition and control of the scanning unit. The pre-formatting was performed by the ATIP method (Absolute Ti, 5 me In Pre-groove). For this purpose, the slot is horizontally modulated, and in particular at a frequency (22.05 kHz) proportional to audio scanning. This frequency also acts to synchronize the CLV servo of the recording unit and / or the reproducing unit. This frequency, in turn, is phase-modulated in bi-phase form to ATIP data. The achievable data rate is then relatively low but still sufficient to store the absolute weapon-10 digest as described above.

As the data is being written to and read from the storage medium, the ATIP information can be continuously read and fed through the signal line 14 to the control unit 8. For the MOD disk, this is done so that the ATIP information can be read and written by a laser a career retaining device that also works while writing and reading.

The time portion of the memory medium containing such ATIP information is mentioned in the following ATIP block. With MOD, the format is made so that 98 EFM frames are stored or read during the ATIP block.

By means of the recording medium described above, it is also possible to find, by means of ATIP, positions which have not yet been explained in a preformed groove. The resolution is then determined by the number of EFM frames, i.e. here the 98 frames. With the described MOD format and scanning speed of 1.2 m / s (as on CD), the EFM frame length is 136.05 ps, which means that the ATIP block is 13.3 ms or 1/75 s.

A specific ATIP (n-1) block is always scanned with the prior ATIP (n-1) block read. If this block is decoded, it is known that the desired block immediately follows next and can now be read or described.

To scan, proceed as follows:

• »I

* *

1. read the ATIP in question

• 2. Deciding whether to wait at most 1 round or jump jump 3. 3. Mechanic jump command 4. Read from ATIP (possibly random) item 6 111108 5. Decide whether to wait for a new career jump for repair or just wait at most 1 round <6. read ATIP. Until ATIP (n-1)

The desired recording is done by caching the digital data to be stored, as mentioned above, and reading it out bursts at a standard data rate of CD storage, i.e. 1.4112 Mbit / s, for storage. Each cache data burst is stored on the storage medium in a continuous form in a respective assigned group of sectors having a fixed number (98 in each case) of ATIP blocks and EFM frames.

Thereafter, the time corresponding to the reduced net data rate for new positioning.

10 When the cache is full again, the writing device (laser optics and magnetic head) should have arrived again at or just before the end of the most recently written sector group. To accomplish this, the number of frames per sector group must be greater than or equal to the product of the reduction factor K and the maximum number of frames per revolution (about 15,200 at the outer edge of the CD). In the case of data MSC reduction, the reduction factor K is 0.25, and therefore the number of frames per sector group should be at least slightly higher than 555.

Because of the unambiguous addressability through ATIP, the length of the sector group is an integer multiple of the length of the ATIP.

If the recording is interrupted at some point, due to interleaving in the interleaving memory 9 of the Reed-Solo mon encoder 9, the CIRC encoding section still contains data belonging to the previously stored data. In this case, the coding part may be stopped, and restarted as the next sector group is written, and thus other data may be written at the beginning of the next sector group.

25 This is not always easy to implement because it is not always possible to stop the equipment immediately and there is a risk of inaccurate interconnection of data elements.

As a result, the current sector group is not completely populated with the payload, but the payload coding is earlier aborted in response to the interleaving length, and the slot-30 memory is then only written blank at the end of the sector set.

In addition to the order of interleaving, it must be borne in mind that for a sector group deposit, the scanning unit or the write / read unit must first be switched from reading to writing. However, the scanning unit (laser) cannot always do this very quickly and accurately. As a result, some data is often lost at the beginning of a sector group. Therefore, some ♦ blank data is written at the beginning of the sector group, here 1-3 EFM frames.

For each sector group, the one-time loss of the first-to-be-placed blank data and the write-down at the end of the interleaving memory is considered to be small, the sector group may not be kept as short as possible. Also, due to the fundamental flexibility of the organization of the stored data and of the storage medium, which of course cannot be lost by cluster recording, the sector group cannot be arbitrarily long.

10 For MOD 13, the following sector group length is used here for 1Cl cluster recording:

Icl = 1176 EFM frames = 12 ATIP blocks = 0.16 s

Within a sector group, the distribution is as follows: EFM frames Contents 15 1 link frame 2 run-in 1029 data 111 interleaving 2 run-out 20 1 link frame 30 disabled This implementation results in a sector group that can store 24696 bits of payload data, which in fact, it requires 28224 bits of space. The loss of memory capacity is 1/8 = 12.5%.

Another consequence of this selection above is that the reduced useful data tact ^ ·. is in simple relation to 'normal CD': 1/4 * (1 -1/8) = 7/32

Gross recorded data rate has been reduced to a quarter due to cluster recording. However, due to 30 1/8 loss, the net amount is only available at 7/32 of the standard data rate.

8 111108

Thus, the achievable net data rate is in the above case: 7/32 * 1.4112 Mbit / s = 308.7 kbit / s This corresponds to the guideline quantization of 3.5 bits per sample, which is very possible with modern data reduction methods such as the one here MSC. 5 Due to the simple sharing ratio 7/32, simple synchronization of external data reduction sources with the storage carrier is also possible in the described arrangement.

In summary, cluster recording means that payload data is not sequentially stored, as in normal CD format, 7350 EFM frames per second, each with 10 usable bytes. Instead, the deposit is made in groups of sectors, which, though as such, consist of consecutive EFM frames, but deposit between groups is not continuous. As a result, each sector group can optionally be assigned for reading, and especially for writing, without destroying the information stored in the upstream or downstream groups.

Also, due to the sufficiently long openings, no special measures are required for rapid switching on or off of the laser for the sector group selective writing assignment.

After writing a sector group, a pause is created, which is used to position the beginning of the next sector group. To find the beginning of the next sector group, the ATIP blocks at the end of the next sector group are decoded. Thus, the positioning can be done so that the entire last group of sectors is read again before immediately following the next one. In this case, deposit errors can be determined so that, due to their excessive error rate, the deposit can be completely cut off or at least be warned to the user.

25 Bug fixes are still under development for debugging. For this purpose, data from the most recent sector group is cached. · There are two strategies for debugging:

First, reposition the beginning of the invalid sector group and rewrite its data again. Immediately after this comes the next sector group da-30. However, time is used for positioning so that the pause between two write cycles may not be long enough to position, read a correction, reposition, and write a correction.

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Since a storage error may also be associated with a defective location in the storage medium, it is better to repeat the writing of the data of the incorrect sector group to the next sector group and then write the next data to the subsequent sector group. The invalid sector group is then marked so that it can simply be skipped over, 5 when read out.

The marking is made at the beginning or end of the UTOC (User Table Of Content) directory or a specific sector group at the beginning or end of the continuous sector group deposit in question. It is also possible to mark the next sector group, which has been re-written for correction, (for example, by another sync word), so that it denotes the error of the previous sector group. However, this means that you must always read one sector group in advance.

Computer data storage based on an operating system such as MS-DOS occurs in blocks of 1024 bytes. If the sector group is implemented according to the above information, then 24 blocks with 1024 useful bytes and possibly additional bits for 15 error protection may be automatically stored in a sector group with at least 1029 usable EFM frames. Because addressability is also defined, cluster recording is also suitable for storing data on a computer.

Due to the lengthy deposit, which has a duration of 0.16 s and associated pause of 0.48 s before depositing the next sector group, a positioning strategy has been arranged since it cannot be assumed that the laser is at the very beginning of the next sector group after the break.

The possible strategy to explain the logical flow is explained below; a deviation from this is, of course, possible.

The data produced by the voice data reduction method from the MSC encoder 4 at 25,308.7 kbit / s is cached as described above into a cache 6 or a swap buffer.

The reading rate is 308700 Hz and the reading rate is 1411200 Hz. The length of each buffer is 197568 bits = 24696 bytes each.

9V *

The writing of the first sector group begins with block ATIP (n). When 1143 EFM frames have been written, writing will stop. After that, the 0. * s wait time for the next * 30 will indicate 'Data ready'. Now scanning in block ATIP (n + 12). To do this, you must skip a maximum of four grooves. In addition, waiting times of up to one lap may be necessary. Now you can write the following sector group, etc.

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Up to 400 ms is available for full positioning. During this time, the positioning must be definitively completed.

It can be assumed that jumping to the next inner neighbor track can be performed with great certainty. Therefore, the following strategy is also possible:

The writing of the first sector group begins with block ATIP (n). When 1143 EFM frames have been written, writing will stop. Immediately after this, one slot is jumped inward and scanning of the block ATIP (n + 12) is started. This is repeated until cache 6 indicates 'Data ready'. When ATIP (n + 12) is found the next 10 times, then another sector group will be written. At the end of this writing, there will be a further leap in career, and now we are looking for ATIP (n + 24), etc.

In the context of this strategy, it is advantageous to have only one career at a time; perhaps this happens more often. At the latest one lap after the 'Data ready' notification, the deposit for the next sector group can begin.

If, after writing the first sector group, the ATIP (n) block is first scanned, i.e. after the newly written sector group is started, then the newly written data can be read for checking. Evaluation of errors that occur may result in appropriate actions, such as warning signals or error rate indication.

20 If unreadable errors are detected during check reading, then the sector group identified as incorrect in block ATIP (n) can still be written in block ATIP (n + 12). This is logged appropriately in the UTOC (User Table Of Content) to skip over the invalid sector group in block ATIP (n) during playback. For displaying the 25 writes in connection with the error case described, the cache 6 is suitably implemented e.g. as a cyclic triple swap buffer.

*; · The above method is not defined for data reduction and a specific data reduction method such as here for MSC. Likewise, recording on a recording medium and playback may be performed on non-reduced data and / or which has a reduced data rate by other data reduction methods.

Another possibility for data storage or playback would be to cache or read from the MSC the reduced data rate burst onto the storage medium and then insert a pause which is three times the length of the record after a specified recording or playback time. In this way 25% of the storage medium can be filled in one turn. When the rest is reached, the 3/4 pause can again be used. head to the top and in the second round fill 25% of the disc or read the disc, etc. This requires difficult organization of the disc contents. In this case, the recording medium contains only "5 normal programs or only reduced data programs." The specified jump from the end to the beginning of the career is crucial.

In principle, another option, regardless of the solutions described above, would be to reduce the scan rate in response to a reduction factor. The same constant wavelength of the storage medium would automatically produce a quarter of the download data rate and four times the playback time at a reduction factor of 1/4. However, the CLV system must be connectable. In addition, the signal correction circuits from the recording medium receive only signals having a quarter of the normal frequency, and must therefore be switched. The mixing of 'normal' deposits with those of reduced data on the same disk is only possible when a fast switching of CLV from 15 to 1/4 to 4 is possible.

The invention can also be used to record digital signals onto and / or play back on magnetic tape with PCM signals, or to record signals on a DAT tape (Digital Audio Tape) in a DAT recorder. The organizational structure of the DAT deposit can be defined, with minor modifications, in the same manner as in the method described in Figure 20 above.

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Claims (17)

1. A method for storing and / or reproducing digital data batches, in particular audio and / or video data batches of net data rate, on scannable, in particular rotating, storage media having at least 5 tracks storing data batches during and during bursting during the iteration step, characterized in that - each burst of data stored or already stored on the storage medium is stored in a slot segment on the storage medium, hereinafter called clusters, using a predetermined physical write data rate irrespective of the net data rate net data rate, - the net data rate is less than a predetermined write data rate or scan-15 node burst data items are cached to a recording and / or reproducing device using a cache (6) to convert the net data rate of data to be recorded to the write data rate or to convert the read rate data to a net data rate of for a pause, and that during the pause that follows the reading or writing of the cluster or burst, the scan / record or playback unit sits at the beginning of the next upcoming cluster or burst. • · »» « A method according to claim 1, characterized in that the net data rate of the data to be recorded is reduced using the data reduction process. A method according to claim 1 or 2, characterized in that, regardless of the net data rate of the data burst, it is always stored at the same physical recording data or write data rate on the storage medium. A method according to claim 1, 2 or 3, characterized in that each data burst is recorded on a storage medium using CD-standard recording parameters or a standard CD-recording data rate of 1.4112 Mbps. Method according to one of the preceding claims, characterized in that each data burst is provided with at least one address data item to indicate its location on a storage medium and / or that each data burst is provided with at least one address data item to indicate the location of the next data burst on the storage medium. Method according to one of the preceding claims, characterized in that the data items to be stored are provided with an error protection code, preferably a Cross-Interleaved-Reed-Solomon-Code (CIRC) error protection code, and / or that the data items to be stored are interleaved (code division); that data batches are stored on the storage medium by channel coding, preferably by means of an eight to fourteen modulation (EFM) code, which structures the data batches into corresponding EFM frames, wherein each EFM frame preferably contains 24 bytes of payload data. Method according to one of the preceding claims, characterized in that before writing the cluster, the previously written cluster is read and / or, in the case of incorrect recording of the cluster, the recording is repeated in the next cluster and / or that the incorrect cluster is marked. Recording medium, preferably a Magneto-Optical-Disc (MOD) or Compact Disc (CD) disc having at least one track for storing digital data batches, in particular audio and / or video data batches, which data batches are stored in any one of claims 1-7. characterized in that each data burst is provided with an address data item to indicate its location on the storage medium 20 and / or an address data item to indicate the location of the next data burst on the storage medium. Recording medium according to Claim 8, characterized in that the groove has a ♦ helical shape and / or that the spiral groove of the recording medium is preformatted and contains data items for identifying the absolute position on the recording medium. Recording medium according to claim 9, characterized in that the helical groove is preformatted with the Absolute Time In Pre Groove (ATIP) method and / or that each location data batch preformatted with the ATIP method forms an ATIP block, preferably having a length of 98 The recording length of the EFM frame and / or that the length of the cluster corresponds to an integer multiple of the ATIP block length, preferably 30 times the ATIP block length. * Recording medium according to one of the preceding claims 9 and / or 10, characterized in that the helical groove is horizontally modulated, preferably at a frequency fprop proportional to the audio standard CD scanning frequency (44.1 kHz). 14 111108 Recording medium according to one of the preceding claims 8 to 11, characterized in that the number of EFM frames per cluster is greater than or equal to the product of the reduction method K of the reduction method and the maximum number of frames per revolution of the rotating medium. 555 EFM frames, preferably 1176 EFM frames. 12 111108 Storage medium according to claim 12, characterized in that the cluster 1176 EFM frames consist of three EFM frames for start, 1029 EFM frames for useful data, 110 EFM frames for interleaving memory allocation, 34 EFM frames not in use or are 10 for the end. Recording device and / or reproducing device for the recording medium (11) according to one of the preceding claims 8 to 13 and / or for carrying out the method according to one of the preceding claims 1 to 7, characterized in that the recording and / or reproducing device is cache (6) for storing burst data items 15, that the cache read rate differs from the read clock rate, that when recording, the read clock rate is greater than that the playback during the pause, the scan / -20 recording or playback unit will be positioned at the beginning of the next incoming cluster or burst. Recording device according to claim 14, characterized in that the data items produced by the encoder (4) of the data reduction method are assigned to the cache (6), which cache (6) is preferably implemented as a cyclic triple swap buffer. Recording device according to claim 14 or 15, characterized in that the frequency fprop, proportional to the audio standard CD scanning frequency, is modulated in a bi-phase format of the data batches so that the recording and / or scanning unit can be switched at the beginning of the cluster recording process. 30 A recording device according to any one of claims 14 to 16, characterized in that the recording device includes an encoder and / or decoder for reducing or decrypting the data, that the encoder (MSC) reduces the net data rate of the datapelkistyksen. 15 111108