JP3138116B2 - Disc playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a CD-I (Compact Dis
c Interactive) format or CD-ROM XA
(Compact Disc Read Only Memory eXtended Architect
The present invention relates to a disk reproducing apparatus for reproducing a disk interleaved at a constant period, such as an ADPCM audio sector of the ure) format.

[0002]

2. Description of the Related Art According to the standards of CD-I and CD-ROM XA, the physical format of data on a disc is as follows.
For example, it is as shown in FIG.

FIG. 6 is an explanatory diagram of two types of physical formats according to the CD-I standard.

[0004] In FIG. 6, the “form 1” of one block physical format according to the CD-I standard includes a synchronization signal 11, a header 12, a subheader 13, and a user data 1.
4, an error detection code parity 15, and an error correction code parity 16. "Form 2" includes a synchronization signal 21, a header 22, a subheader 23, user data 24, and an error detection code parity 25.

[0005] Further, the header 12 (22) includes minute 12a, second 12b, frame 12c, and mode 12d as sector addresses. The subheader 13 (23)
Consists of a file number 13a, a channel number 13b, a sub mode 13c, and coding information 13d.

Although the physical format of the CD-ROM XA is slightly coarser than that of the CD-I standard, it is basically the same.

That is, for all sectors, in addition to the user data 14 and 24 serving as the data body, the subheader 13 and
There is always a part called 23, and in that sector unit,
It is possible to distinguish between audio, video, and data for a computer.

Conventional CD-I and CD-ROM XA
In the disk reproducing apparatus, the host computer outputs a read instruction or an ADPCM data reproduction instruction to a CD-ROM controller usually composed of a microcomputer. At this time, the host computer determines the sector address (minute 12a, second 12b,
The value of the file number 13a or the channel number 13b indicated in the frame 12c) and the subheaders 13 and 23 is also specified.

In the CD-ROM controller, after the seek by the sector address of the file to be reproduced is completed,
Check the information in the subheaders 13 and 23 of each sector,
It is determined for each sector whether the sector is requested by the host computer. In addition, usually, the CD-ROM controller can also acquire information on whether or not the subheaders 13 and 23 include an error at the time of this read or ADPCM reproduction.

[0010] CD-I format and CD-ROM
In the XA format, 8 bits are allocated to the sub-headers 13 and 23, and 4-bit information is written twice to take measures against errors. However, errors may still occur in the subheaders 13 and 23. Assuming that the subheaders 13 and 23 to be checked for each sector are errors, the CD-ROM controller attempts to read the sector again or gives up and discards the sector and treats the sector as having no sector. I was doing it.

[0011]

However, ADPCM (A
daptive Differential PCM) If the data is meaningful when it is played back in real time, such as audio, even if retry is performed and the correct data is obtained, the audio playback is temporarily interrupted and silence occurs. Conversely, a trouble such as generation of noise occurs. Similarly, if you discard that data,
The data is not reproduced, and silence occurs, and noise occurs temporarily.

Therefore, according to the present invention, even if there is an error in the subheader, the sector is stored in the host computer, ADPC.
It is an object of the present invention to provide a disk reproducing apparatus capable of transferring data to an M decoder or the like in real time.

[0013]

According to the present invention, there are provided sector address information of a sector being reproduced, sector property information indicating the property thereof, a judgment means for judging an error in the sector property information, and past sector property information. Interleave cycle determining means for determining an interleave cycle according to: an arithmetic means for calculating an interleave length between a sector address being reproduced at present and a sector address one cycle before; and a sector being reproduced when an error is determined by the determiner. When the property information is estimated as sector property information one cycle before, and when the arithmetic means confirms that the interleave lengths match, the sector property information estimating means determines the sector property information as the sector property information one cycle before. It is provided.

[0014]

According to the present invention, a CD-I or CD-ROM
In the XA file, sectors are fixed at regular intervals according to the standard such as the ADPCM sector (fixed-length interleaved). To access a file, first, the CD-ROM controller uses the host computer. If a sector to be transferred to the ADPCM decoder or an error-free sector is found in the subheader, the header information as the sector address is stored. Thereafter, the header information is stored for each sector having no error each time the sector is read. When a sector having an error in the subheader is found, the fixed interleave length is added to the sector address transferred one cycle before. If the result matches the current sector address, it is determined that the sector is a sector to be transferred, and the value of the erroneous subheader is estimated from the repetition timing and corrected. Therefore, even if an erroneous sector is found in the subheader, that sector can be transferred to the host computer or ADPCM decoder in real time.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a CD-I player as a disc reproducing apparatus according to one embodiment of the present invention will be described.

FIG. 1 is a block diagram of a disk reproducing apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 30 denotes a host computer for controlling the entire CD-I player;
1 (see FIG. 2), a CD drive 32 reproduces CD-ROM data read out by the CD drive 31 from the ADPCM.
CD-ROM decoder for converting to data, 33 is ADP
An ADPCM decoder that converts CM data into an audio signal. Numeral 34 controls the CD drive 31 according to a command from the host computer 30, seeks the sector address (minute 12a, second 12b, frame 12c), and every time a sector address is detected, the CD-RO
A CD-ROM controller that outputs a read signal to the M decoder 32. Reference numerals 38 and 39 denote DRAMs, and reference numeral 40 denotes a video controller. The video read by the CD-ROM decoder 32 is written to the DRAM 38 or the DRAM 39, sequentially read out and output as a video output.

A ROM 35 stores a program for controlling the disk reproducing apparatus of this embodiment, and a CD 36 stores a CD.
-NVRA for writing a signal read by ROM decoder 32
M and 37 are calendars.

Next, the functions of the CD-ROM controller 34 and the CD-ROM decoder 32 will be described with reference to FIG.

FIG. 2 shows a CD-ROM controller and a CD-ROM used in a disk reproducing apparatus according to one embodiment of the present invention.
FIG. 3 is a functional block configuration diagram illustrating the configuration functions of a decoder.
Here, the description is based on the premise that the physical format of “Form 1” according to the CD-I standard is used.

In FIG. 2, when the host computer 30 starts reproducing or reading a specific file, the host computer 30 first sends the microcomputer 34a of the CD-ROM controller 34 the minute 12a, the second 12b,
Sector address of frame 12c, etc., file number 13
a and an instruction indicating the channel number 13b.

In the CD-I and the CD-ROM XA, a plurality of types of data can be mixed in one file. Therefore, in this embodiment, it is assumed that ADPCM audio and data are configured as one file.

The host computer 30 converts an ADPCM data sector in one file into an ADPCM decoder 33.
At the same time, the normal data sectors are also commanded to be transferred to the NVRAM 36 of the host computer 30. The type of this sector is identified by the sub header 13
According to the information of the channel number 13b, submode 13c and coding information 13d in the
This is performed by the CD-ROM controller 34. In this process, the command buffer unit 32d of the CD-ROM decoder 32 receives a command from the host computer 30,
The data processed by the ROM decode processing unit 32a is determined by the header / subheader at the current position and its error information determination unit 32b, and when there is no error, the switch 32e controlled by the data transfer control hardware unit 32c is used. To the NVRAM 36 of the host computer 30.

At this time, the CD-ROM controller 34
In the header save memory 34b and the sub-header save memory 34c.
23 is written. Further, when instructing the reproduction of the file, the host computer 30 specifies the sector included in the file to be reproduced by specifying the channel number 13b. The CD-ROM controller 34 transfers only the sector having the selected channel number 13b among the specified files.

The CD-ROM decoder 32 is shown in FIG.
The processing is performed as follows.

FIG. 3 is a flowchart of a CD-ROM decoder used in the disk reproducing apparatus according to one embodiment of the present invention.

First, in step S01, when there is no error, it is determined whether the sector should be handled without ignoring it.
When there is an error and the sector is ignored, the routine exits. If there is no error, in step S02
The header 1 in the header save memory 34b and the sub-header save memory 34c built in the ROM controller 34;
2 and 22, and the information of the subheaders 13 and 23 are written. The contents of the subheader are determined by the standards of CD-I and CD-ROMXA, and the determination of the interleave cycle can be performed by examining the subheader. In step S03, it is determined whether the command from the audio sector and the host computer 30 is an ADPCM reproduction command for transferring to the ADPCM decoder 33,
If it is determined that the command is an ADPCM reproduction command for performing transfer to the ADPCM decoder 33, the process proceeds to step S04.
It outputs a transfer start trigger to the M decoder 33 and transfers it to the ADPCM decoder 33 via the switch 32e. Also, an ADPC for transferring to the ADPCM decoder 33
If not determined to be an M playback command, a transfer start trigger to the host computer 30 is output in step S05,
The data is transferred to the NVRAM 36 via the switch 32e.

On the other hand, when the CD-ROM controller 34 receives a command from the host computer 30, it outputs a command to the CD drive 31, seeks the sector address, and drives the CD near the target address and slightly before the target address. The head of the drive 31 is moved. CD-
Every time a sector address is detected, the ROM controller 34 is interrupted by a signal generated by the CD-ROM decoder 32. Normally, the current address and the sub-header 13 are checked for each interrupt, and it is determined that the address matches the target sector address. wait. At this time, the CD-ROM controller 34
In the header save memory 34b and the sub-header save memory 34c.
23 is written. Header save memory 34b
The headers 12, 22 and the sub-headers 13, 23 for writing in the sub-header save memory 34c are at least one cycle or more of the headers 12, 22, the sub-header 13,
It has a capacity to write 23 information. The CD-ROM controller 34 also checks error information of the header 12 and the subheader 13 held by the CD-ROM decoder 32. Although the subheader 13 is written twice according to the standard, an error in the subheader 13 here means that both pieces of information are errors.

When it is detected that the target address has been reached,
It is the sector address requested by the host computer 30 and starts the transfer of the user data 14. Based on the signal generated by the CD-ROM decoder 32 under the control of the CD-ROM controller 34, the host computer 30 knows that the data has been prepared by an interrupt or the like, and reads the data. Here, assuming that an interrupt is used, an interrupt process of the CD-ROM controller 34 shown in FIGS. 4 and 5 will be described.

FIG. 4 is a flowchart of an interrupt process of the CD-ROM controller used in the disk reproducing apparatus according to one embodiment of the present invention. FIGS. 5A and 5B show FIG.
5 is a flowchart of a process of a routine A and a process of a routine B used in FIG.

First, if the file number is not the corresponding file number specified in step S1, the corresponding sector is ignored in step S2, and the routine exits. When the file number is the corresponding file number, the subheader 13,
It is determined whether there is an error in the sub-mode 13c in 23. If there is an error in the sub-mode 13c, normal error processing is performed in step S4. Here, the reason why the submode data is not to be estimated is that it contains information having no periodicity. If there is no error in the sub mode 13c, it is determined in step S5 whether there is an error in the other sub headers 13 and 23, and the sub header 1 excluding the sub mode 13c is determined.
When there is an error in the save flags 3, 23, it is determined in step S6 whether the save flag has been reset. When the save flag has been reset, normal error processing is performed in step S7. If it is determined in step S6 that the save flag has been set, the process of routine B is performed in step S8. If it is determined in step S5 that there is no error other than the submode 13c in the subheaders 13 and 23, the process of the routine A is performed in step S9.

When the routine A is called in step S9, the headers 12 and 22 and the subheaders 13 and 23 are checked in step S11, and it is determined in step S12 whether the length is a fixed interleave length. escape. If it is determined in step S12 that the length is a fixed interleave length, then in step S13 the header 1
2, 22 and the subheaders 13, 23 are saved, and a save flag is set in step S14.

That is, the transferred sector does not always have the fixed-length interleave. Especially the current CD
In the I- and CD-ROM XA standards, the fixed interleave length sector is only ADPCM.
It is confirmed that c indicates an ADPCM audio sector. If the sector transferred here has a fixed interleave length, the CD-ROM controller 34
At this time, information of headers 12 and 22 indicating addresses and information of submodes 13c and coding information 13d, which are information of subheaders 13 and 23 indicating the characteristics of the sector, are stored.

The coding information 1
By examining the value of 3d, the type of audio data, such as level A / B / C-stereo / monaural, can be distinguished, and this determines the interleave length. However,
In this embodiment, the headers 12 and 22 and the subheaders 13 and 2
As long as there is information indicating fixed-length interleaving in 3 or the like, the data is not limited to audio data, and sector data such as video data and moving image data may be used for any purpose.

When the routine B is called in step S8, the header address saved in step S21 is compared with the current header address, and in step S22, it is determined whether or not the comparison result matches the saved fixed interleave length. If they do not match the fixed interleave length, normal error processing is performed in step S23. Exit this routine. When the comparison result matches the saved fixed interleave length in step S22, it is determined in step S24 whether or not the channel number 13b has an error.
If there is an error in 3b, the channel number 13b saved in step S25 is set as the current number. In step S26, it is determined whether there is an error in the coding information 13d.
13d coding information saved in
Is the current coding information 13d,
Exit this routine.

That is, when the command of the host computer 30 includes reproduction of the ADPCM sector, the CD-RO
After the M controller 34 designates the transfer destination to the ADPCM decoder 33 instead of the host computer 30, data transfer is started.

In this case, the data is transferred not by the host computer 30 but by the ADPCM decoder 33. Whether the data to be transferred is to the host computer 30 or to the ADPCM decoder 33, the channel number 13b and the coding information 13 in the subheaders 13 and 23 of the sector are provided.
If the information of d is found to have an error, the CD-R
The OM controller 34 adds the interleave length (sector arrangement interval) of the sector being reproduced to the information of the headers 12 and 22 at the time of the previous transfer that has already been stored, and compares the information with the current header 12. At this time, in particular, the sub-header 13,
23, the sub-mode 13c includes information having a very significant meaning in the operation of the host computer 30.
If there is an error in c, normal error processing is performed. Also, the CD-ROM decoder 32 has a CD-ROM
Some hold information indicating the detection result of the ROM synchronization pattern, and this information can be used for error determination. If the synchronization is correct, the estimation of the sector is almost certain, and if the synchronization is not correct, it is risky to guess the subheaders 13 and 23 of the sector. Become. The correctness of the synchronization
It is general to make a determination based on the fact that the value of the counter of the continuous number of illegal synchronizations is below a certain level. Further, if the comparison result matches the saved fixed interleave length, it is known that the sector is the same type of sector as that of the previous transfer. This sector is reproduced while maintaining the real-time property without being reseeked or discarded as an error. If it is to be transferred to the host computer 30, it is transferred, and if it is to be transferred to the ADPCM decoder 33, it is transferred to the ADPCM decoder 33 for audio reproduction.

Here, the transfer destination of the sector is a CD-ROM.
Although described as an example controlled by the controller 34, the CD-
The ROM controller 34 decides not to make any selection by the subheaders 13 and 23 or only to make selection by the channel number 13b.
Reads the channel number 13b of the sub-headers 13 and 23, the sub-mode 13c and the error information of the sub-headers 13 and 23, and sets the transfer destination to a memory under computer management.
In the method of determining whether to use the DPCM decoder 33, only the difference between the CD-ROM controller 34 and the host computer 30 makes the determination, the control method is the same, and this embodiment can be applied. .

As described above, in the disk reproducing apparatus of the present embodiment, in the disk reproducing apparatus for reproducing the disk 41 of the format composed of sectors interleaved at a constant period, the number of sectors 12a and seconds 12
b, the sector address information including the frame 12c, etc., and the mode 12d and the sub-headers 13, 2 representing the properties thereof.
No. 3 and the like, and step S3 and step S5 for judging an error in the sector property information, and interleave cycle judgment means for step S02 to determine the interleave cycle based on past sector property information. Calculating means for calculating the interleave length between the sector address being reproduced and the sector address one cycle before; and, when an error is determined by the determining means, the arithmetic means confirms a match between the interleave lengths. It is provided with sector property information estimating means comprising steps S24 to S27 for determining sector property information by estimating the sector property information in the middle as sector property information one cycle before.

Therefore, like the ADPCM sector,
For access to files that are interleaved at regular intervals, which are determined by the standard to arrange sectors at regular intervals, first, the CD-ROM controller is a sector to be transferred to the host computer or ADPCM decoder. If an error-free sector is found in the subheader, the header information that is the sector address is stored. Thereafter, the header information is stored for each sector having no error each time the sector is read. If you find an erroneous sector in the subheader,
The fixed interleave length is added to the sector address transferred one cycle before. If the result matches the current sector address, it is determined that the sector is a sector to be transferred, and the value of the erroneous subheader is estimated from the repetition timing and corrected. Therefore,
Even if an erroneous sector is found in the subheader, the sector can be transferred to the host computer or ADPCM decoder in real time.

[0041]

As described above, according to the disk reproducing apparatus of the present invention, a disk reproducing apparatus for reproducing a disk having a format composed of sectors interleaved at a fixed period, wherein the CD-ROM controller is a host computer or an ADPCM. The sector to be transferred to the decoder,
If a sector without error is found in the subheader,
The header information which is the sector address is stored,
If an erroneous sector is found in the subheader, add the interleave length to the sector address transferred one cycle earlier, and if the result matches the current sector address,
Judge that the sector is to be transferred,
The value of the erroneous subheader is estimated from the repetition timing and corrected.

Therefore, even if an erroneous sector is found in the subheader, the sector can be transferred to the host computer or ADPCM decoder in real time. Therefore, even if there is an error in the subheader, the sector can be transferred in real time to a host computer, an ADPCM decoder, or the like, and in the reproduction of data to be reproduced in real time, the reproduction of data can be continued without impairing the real-time property. In the case of ADPCM audio data, interruption of reproduced sound and generation of noise can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram of a disk reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a functional block diagram showing the configuration functions of a CD-ROM controller and a CD-ROM decoder used in the disk reproducing apparatus according to one embodiment of the present invention.

FIG. 3 is a flowchart of a CD-ROM decoder used in the disk reproducing apparatus according to one embodiment of the present invention.

FIG. 4 is a flowchart of interrupt processing of a CD-ROM controller used in the disk reproducing apparatus according to one embodiment of the present invention.

5 (a) and 5 (b) are flowcharts of the processing of a routine A and the processing of a routine B used in FIG. 4;

FIG. 6 is an explanatory diagram of two types of physical formats according to the CD-I standard.

[Explanation of symbols]

 Reference Signs List 30 host computer 31 CD drive 32 CD-ROM decoder 33 ADPCM decoder 34 CD-ROM controller 36 NVRAM 38, 39 DRAM 40 video controller 41 disk

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-259461 (JP, A) JP-A-6-139753 (JP, A) JP-A-4-26956 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G06F 3/06 G06F 3/08

Claims (1)

(57) [Claims] 1. A disk reproducing apparatus for reproducing a disk having a format composed of sectors interleaved and arranged at regular intervals, comprising: sector address information of a sector being reproduced; sector property information representing the property; and sector property information. Determination means for determining an error of the above, interleave cycle determination means for determining an interleave cycle based on past sector property information, calculation means for calculating an interleave length of a sector address being currently reproduced and a sector address one cycle before, and When an error is determined by the determining means, the sector property information being reproduced is estimated as the sector property information of one cycle before, and when the interleave length of both is matched by the arithmetic means, the sector property information is determined by one cycle. Means for estimating sector property information determined as sector property information of Disk reproducing apparatus, characterized in that.