JPH08212695A - Md player - Google Patents

Abstract

PURPOSE: To prevent occurrence of interruption of sound by predicting the interruption time of reproduced sound by a control section based on address data and stopping reproduction until music data of quantity corresponding to this interruption time is stored in a memory. CONSTITUTION: A system controller 1 is provided with an interruption time calculating means 1a predicting the interruption time of reproduced sound based on address data, and a reproduction standby means 1b controlling reproduction so that reproduction is made to stand by until music data of quantity corresponding to this interruption time is stored in a memory. And To is calculated based on address information and information of a time required for access. And when To>o is given, that is, when interruption of reproduced sound is caused (step 4), operation is shifted to step 5. When To is zero or negative, as interruption of reproduced sound is not caused, normal processing is continued.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an MD (mini disc).
The present invention relates to a player, and more particularly to an MD player which reproduces data recorded in a discontinuous area.

[0002]

2. Description of the Related Art The structure of a conventional MD player is shown in FIG.

The optical pickup 51 reads a recording signal on the disk 50C by reflecting laser light. The optical pickup 51 moves to an arbitrary position on the disk 50C based on the drive control by the servo control circuit 53 (hereinafter referred to as access).

The RF amplifier 52 amplifies the signal read by the optical pickup 51 to an appropriate level as an electric signal.

The servo control circuit 53 includes an optical pickup 5
1 is made to follow the signal train on the disk 50C, and the optical pickup 5 is instructed by the system controller 59.
1 is moved to the target position on the disk 50C.

The EFM and ACIRC decoder 54 are MD
EFM decoding that is the modulation of the recording data of 50 and ACIRC decoding that is the error correction are performed.

The memory controller 55 is a disk 50.
The data read from C is shockproof memory 5
Write to 6. Also, the data is read from the memory 56. As described above, by using the memory 56 as a buffer at the time of reproduction, it is possible to eliminate skipping due to vibration and to edit a recorded MD.

As the shock proof memory 56, a 4-Mbit DRAM is used here. 4 Mbi
It is possible to buffer a reproduction time of about 12 seconds at t.

The ATRAC decoder 57 performs decoding of ATRAC which is a MD data compression method. After this decoding, it becomes 16-bit linear PCM audio data.

The 16-bit D / A converter 58 converts 16-bit linear PCM audio data into an analog signal.

The system controller 59 sends an instruction to each block of what is requested by key input and realizes it, and displays necessary information. Here, it consists of a microcomputer and its software.

Next, a conventional reproducing operation will be described with reference to FIG.

Since the MD player compresses and records the data, the optical pickup 51 is much faster than the data rate (0.3 [mbit / s]) required for reproduction (1.4 [mbit / s]). s]) data to disk 5
Reading from 0C. Therefore, the data is temporarily stored in the shock proof memory 56, and this is used as a buffer to read the data from the memory 56 for reproduction. This makes it possible to eliminate skipping due to vibration and edit a recorded MD.

That is, the data is the shock proof memory 5
If the data is stored in No. 6, even if the optical pickup 51 is deviated from the disk 50C due to vibration and cannot read the data, the data stored in the shock proof memory 56 can be continuously reproduced. That is, as long as the data in the shock proof 56 is not empty, the voice can be continuously output.

When the user randomly records and erases music on the recording MD several times, the recording areas may remain discontinuously scattered in the disc 50C. Even in such a case, the vacant areas that have been separated can be totaled and recorded as one area. This means that even if one song is recorded in a discontinuous area,
Random access of the optical pickup 51 and temporary storage in the shock proof memory for replaying allow for continuous replay without problems.

The relationship between the reading from the disk 50C and the amount of data in the shockproof memory 56 will be described with reference to FIG. In the MD player, since the signal read from the disc 50C at 1.4 [Mbit / s] is a compressed signal, it is 0.3 in decoding and reproducing it.
Only [Mbit / s] is required. Therefore, the signal of the disk 50c is read out intermittently.

In normal reproduction, when the maximum amount is stored in the shock proof memory 56, the reading from the disk 50C is awaited. Shockproof memory 5 by playback
The amount of data from 6 decreases, and when it becomes less than a certain amount, the maximum amount is read again.

FIG. 10 is an explanatory diagram showing an example of the case where one piece of music is recorded in the disc 50C divided into discontinuous areas. In the case where the recording is divided into the discontinuous areas as described above, the reproduction is performed according to the flowchart shown in FIG. As a result, it is reproduced as one continuous song.

FIG. 11 is a flowchart showing a conventional reproducing process, and FIG. 12 is a time chart corresponding thereto. First, the point A, which is the beginning of the music to be reproduced, is accessed (step S51). When the access is completed and the point reaches the point A, data reading is started from that point (step S52). The read data is stored in the shock proof memory 56 via the RF amplifier 52 and the decoder 54.

When the song data is stored in the shock proof memory 56, the ATRAC decoder 57 is stored in the memory.
And the reproduced sound is output (step S53). Since the data reading speed is faster than the playback speed,
Data is successively stored in the shock proof memory 56. When the shock proof memory 56 is full, the reading process is suspended. Further, when the data in the shock proof memory 56 becomes a certain amount or less, the reading is restarted.

When the point B, which is a discontinuous point, is reached (step S54), the data reading process is stopped (step S).
55). Next, the point C, which is the start position of the discontinuous point, is accessed (step S56). During the access processing to the point C, the data is not read and the data in the shock proof memory 56 is reduced by the reproduction. However, playback will continue unless the memory is empty.

When the access is completed and point C is reached, data reading is restarted. As a result, the data in the shock proof memory 56 increases.

[0023]

However, when the reproduction is performed by the conventional method, the reproduction may be interrupted. This is because, as is clear from FIG. 13, since the distance between A and B is short, the amount of data that can be stored in the shock proof memory is small. This break in the sound is due to the short AB portion immediately after the beginning of the song, so even if there is such a short portion in the middle of the song, there is a sufficient amount of data in the shockproof memory before that. Since it is accumulated, no problem occurs.

That is, in the case where A is the beginning of a song and AB is short, there is a disadvantage that a sound break occurs when this song is cueed (selected).

[0025]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the conventional example, and in particular to provide an MD player in which the reproduced sound is not interrupted even during the reproduction of the data recorded in the discontinuous area. To that end.

[0026]

Therefore, in the present invention, M
An optical pickup for reading a recording signal on D, a modulator for modulating the recording signal into digital data, a memory for accumulating a certain amount of the address data and the music data, which are the digital data, and an address data in the memory. The optical pickup is driven and controlled to store music piece data in the memory, and a reproduction system for reading the music piece data from the memory and decoding the D / A converted data for external output.

Moreover, the control section predicts the discontinuity time of the reproduced sound based on the address data, and the reproduction standby control until the amount of music data corresponding to the discontinuity time is accumulated in the memory. And a reproduction standby means for performing the reproduction. This aims to achieve the above-mentioned object.

[0028]

The optical pickup reads a recording signal on the MD, and the modulator modulates the recording signal into digital data. Then, a certain amount of address data in the digital data is accumulated in the memory. Then, the control unit drives and controls the optical pickup on the basis of the address data in the memory to store the music data, which is digital data, in the memory. Further, the reproducing system reads out the music piece data from this memory, decodes it, and then D / A-converts it for external output.

Further, the control unit predicts the interruption time of the reproduced sound based on the address data, and when the interruption time is calculated, until the amount of music data corresponding to the interruption time is accumulated in the memory. Controls to stop playback.

[0030]

An embodiment of the present invention will be described with reference to the drawings. The same components as those of the related art will be designated by the same reference numerals and the description will be applied accordingly.

FIG. 1 is a block diagram showing the configuration of an MD player according to the present invention. The MD player includes an optical pickup 51 that reads a recording signal on the MD 50, a modulator 54 that modulates the recording signal into digital data, and a memory (shock proof memory) that stores a certain amount of digital data such as address data and music data. ) 56,
The system controller 1 is provided as a control unit that stores the music data in the shock proof memory 56 by driving and controlling the optical pickup 51 based on the address data in the shock proof memory 56.

The reproducing system 3 includes an ATRAC decoder 57 for decoding the music data from the shock proof memory 56, and a 16-bit D / A converter 58 for D / A converting the decoded data and outputting it to the outside. .

In addition, the system controller 1 reproduces the interruption time calculating means 1a for predicting the interruption time of the reproduced sound based on the address data, and the reproduction until the amount of music data corresponding to the interruption time is accumulated in the memory. A reproduction standby unit 1b for standby control is provided.

This will be described in detail.

In the MD50, the TOC (Table of Contents) and the UTOC (U
ser Table of Contents: and a table of contents for users). In this TOC, etc., the disc name, each song name,
The address etc. where each song starts are described. The MD player accesses the recording signal based on the address described in the TOC or the like. Therefore, the disk 5
When reading from 0C, the TOC or the like is first read, and then the data of each song is accessed based on the address described in the TOC or the like.

The TOC and the like also include character information such as song titles and have a large amount of data. Therefore, an area is secured and stored in the DRAM used as the shock proof memory 56. Therefore, the system controller 1 controls access based on the TOC and the like on the DRAM. Here, the shock proof memory 5
It is assumed that this TOC is recorded at a specific address portion in 6.

Addresses are given to the entire circumference of the MD. The address is in units of clusters and sectors, and one cluster is 32 sectors. 1 sector is 23
It is the minimum unit for reading and writing from the disk 50C, which is composed of 52 bytes.

In the MD player, the reading time (T _W )
Is 13.4 [msec / sector]. Therefore, when the sector is S, the reading time is expressed as T _W (S).
Taking the case shown in FIG. 10A as an example again,
The system controller 1 calculates the reading time (T _W ) from the start position A of the music piece to the end position B of the consecutive sectors by using this numerical value.

FIG. 2 is a graph showing a function of time required for access. The time required for access varies depending on the configuration of the optical pickup 51, the feed motor, and the like, but is a function as shown in the figure. In the figure, the number of sectors S is the absolute value of the address of the access start position B and the address of the target position C, and the unit is a sector. This function is approximated in a stepwise manner as shown in FIG. 3 so that it can be easily used for control.

Further, as shown in FIG. 4, this numerical value is stored in the form of a table as required access time information. That is, the required access time storage unit 2 stores in advance the required time for the access operation as the required access time information for each access distance in units of the number of sectors. The system controller 1 calculates the access time (T _A ) from the end position B shown in FIG. 10 to the start position C at which songs are recorded discontinuously, based on the access required time information.

Further, in the MD player, the reproduction time (T _R ) is 63.9 [msec / sector]. Here, when the number of sectors is S, the reproduction time is expressed as T _R (S). The system controller 1 calculates the reproduction time (T _R ) based on the recorded information from the start position A to the end position B shown in FIG.

The waiting time (T _O ) is the time at which the reproduced sound is interrupted, and is calculated as follows.

[0043] _{T O = T W (| AB} |) + T A (| BC |) -T R (| AB |)

That is, the reading time from the point A to the point B and the access time from the point B to the point C are added, and the reproduction time of the data from the point A to the point B is subtracted from this.

Next, the operation will be described.

FIG. 5 is a flow chart showing the processing steps of this embodiment, and FIG. 6 is a time chart corresponding thereto. Here, the addresses of points A, B, and C are as follows.

Point A: 2098 cluster 10 sectors Point B: 2099 cluster 31 sector C point: 219 cluster 0 sector

Therefore, the distance between the points is as follows.

AB = 1 cluster 21 sectors = 53 sectors BC = 1880 cluster 31 sectors = 60191 sectors

When this is processed by the flowchart of the conventional example shown in FIG. 11, it becomes as follows.

Read: T _W (| AB |) = T _W (53) = 13.4 [msec / sector] × 53 = 0.71 seconds Access: T _A (| BC |) = T _A (60191) = 3 seconds _{Play: T R (| AB |)} = T R (53) = 63.9 [msec / sector] × 53 = 3.39 sec

Therefore, the reproduced sound is interrupted for T _O = T _W + T _A -T _W = 0.32 seconds.

According to this embodiment, the reproduction is waited for 0.32 seconds in the step S5, and the disc 50C is in the meantime.
Since the reading and access from the device is continued, the inconvenience that the reproduced sound is interrupted is avoided. In FIG. 5, first, the point A which is the start position of the music piece to be reproduced is accessed (step S1). Next, reading of data is started (step S2). Next, T _O is calculated based on the address information and the required access time information (step S
3: interruption time calculation means 1a). T _O is expressed by the following equation.

[0054] _{T O = 0.71 + 3-3.39 = 0.32} [ second]

Further, when T _O > 0, that is, when the interruption of the reproduced sound occurs (step S4), the process proceeds to step S5. T _O is when a zero or negative continue normal processing for interruption of the reproduced sound is not generated (step S6). In step S5, controls the memory controller 5 transfers data from the shock-proof memory 56 to the reproduction system delays T _O [sec] minutes with. Here, 0.32
Wait for second reproduction (reproduction standby means 1b).

Then, data reproduction is started (step S6). The subsequent processing is the same as the conventional one. When the access position reaches the point B (step S7), the reading of data is stopped (step S8), and the point C is accessed (step S9). The access to the point C is performed during the reproduction of the data stored in the shock proof memory 56. Next, reading of data is started from point C (step S10).

As described above, according to this embodiment, as shown in FIG. 6, even when the data of one song is recorded (recorded) discontinuously, the reproduced sound after the selection of the song is interrupted. Disappears. Conventional music selection time, in the example of FIG. 12 is two seconds an access time to the point A, in the present embodiment is than T _O min slow conventional Yes 2.32 seconds at point A access + latency However, since the sound break time is accurately calculated and the playback start is delayed only by the break time,
The waiting time can be minimized.

Moreover, since the processing for delaying the start of reproduction is performed only when the reproduction sound is interrupted, normal reproduction can be performed at high speed. In this case, the waiting time from the reception of the reproduction command to the start of the reproduction is shorter than the case where the reproduction is always started after the fixed amount is accumulated. Further, in this embodiment, the point C access time is long (60191 sectors), which corresponds to the end to end of the disk, and is considered to be the worst case. Therefore, the waiting time is usually a little shorter than usual.

[0059]

Since the present invention is configured and functions as described above, according to this, the control unit predicts the interruption time of the reproduced sound based on the address data, and further, when the interruption time is calculated. Controls to stop the reproduction until the amount of music data corresponding to the interruption time is accumulated in the memory, so that the start of the reproduction is delayed and the interruption of the sound can be prevented. Moreover, since the control unit predicts the interruption time and performs this processing, normal reproduction is performed when there is no possibility of sound interruption, and unnecessary waiting time does not occur. Furthermore, since this waiting time is set according to the interruption time, it can be realized with the minimum waiting time. As described above, it is possible to provide an unprecedented excellent MD player in which the reproduced sound is not interrupted even during the reproduction of the data recorded in the discontinuous area.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a graph showing access time in the embodiment shown in FIG.

FIG. 3 is a graph showing an example in which the graph shown in FIG. 2 is stepwise approximated.

FIG. 4 is a chart showing access required time information by the graph shown in FIG.

5 is a flowchart showing an example of processing steps in the embodiment shown in FIG. 1. FIG.

6 is a timing chart showing an operation example in the processing example shown in FIG.

FIG. 7 is a block diagram showing a configuration of a conventional MD player.

FIG. 8 is an explanatory diagram showing data transfer in the configuration shown in FIG. 7.

9 is an explanatory diagram showing normal reproduction by intermittent reading in the configuration shown in FIG.

FIG. 10 is a diagram showing an example of a case where data is recorded in a discontinuous area, FIG. 10 (a) is an explanatory diagram showing positions on the disc, and FIG. 10 (b) shows a data structure. FIG.

FIG. 11 is a flowchart showing an example of conventional reproduction processing.

12 is a timing chart showing an operation example in the processing example shown in FIG.

13 is a timing chart showing a case where sound interruption occurs due to the processing shown in FIG.

[Explanation of symbols]

 1 Control Unit (System Controller) 1a Interruption Time Calculation Means 1b Playback Standby Means 2 Access Required Time Storage Unit 3 Playback System 50 MD 51 Optical Pickup 54 Modulator 56 Shockproof Memory 57 ATRAC Decoder 58 16-bit D / A Converter

Claims (2)

[Claims] 1. An optical pickup for reading a recording signal on an MD, a modulator for modulating the recording signal into digital data, a memory for accumulating a fixed amount of address data and music data, which are the digital data, in the memory. And a control unit for driving and controlling the optical pickup on the basis of the address data to store the music data in the memory, and reading the music data from the memory for decoding, D / A converting and externally outputting the music data. In a MD player having a reproduction system, the control unit accumulates in the memory the interruption time calculation means for predicting the interruption time of the reproduced sound based on the address data, and the amount of music data corresponding to the interruption time. An MD player, which is provided with a reproduction standby means for controlling the standby of the reproduction until the reproduction. 2. The control unit is provided with an access required time storage unit in which the time required for the access operation is stored in advance as access required time information for each access distance in units of the number of sectors. Means for calculating the reading time (T _W ) from the start position A of the music piece to be reproduced on the MD to the end position B of the continuous sector, and the music piece being recorded discontinuously from the end position B Means for calculating the access time (T _A ) to the start position C based on the required access time information, and the reproduction time (T _R ) by the recorded information from the start position A to the end position B. and means, according to claim 1, wherein the interruption time calculation means, characterized by comprising a function of calculating the interruption time (T _O) following equation _{T O = T W + T a} -T R of the sound
MD player described.