JP3724727B2 - Digital audio disc and playback method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital audio disc.And itsIt relates to a reproduction method.
[0002]
[Prior art]
A DVD (digital video disc, digital versatile disc) has a larger capacity than a CD (compact disc), and is therefore attracting attention as an audio disc for music and the like.
[0003]
[Problems to be solved by the invention]
By the way, a DVD can record at a higher density than a CD, and has a sufficient recording time, so how to use it as a music recording medium is a problem. For example, in addition to the original music as a music source, if it can be selectively played back as karaoke or BGM, the user's way of enjoying spreads. In addition, a usage method is desired in which the way of enjoying spreads as the user performs the reproduction operation many times.
[0004]
  In view of the above problems, the present invention is a digital audio disc that allows a user to perform a wide variety of reproductions, and allows a disc manufacturer to use the same disc in different ways.And itsAn object is to provide a reproduction method.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides the following:1) and 2)It consists of the means.
  That is,
  1)When recording to a digital audio disc, an analog audio signal of one or more original music pieces and a bonus music piece to be selectively reproduced separately from the original music piece is A / D converted at a sampling frequency higher than 96 kHz. A step of generating a digital data sequence,
  The auxiliary signal recording area and the main signal recording area are continuously arranged, and include at least a disk identifier for identifying the disk in the auxiliary signal recording area, and in the main signal recording area,
  One or more original music pieces and a bonus music piece for selective reproduction separately from the original music pieceWhenThe,Managing the audio management (AMG),
  A first audio pack which is a component of the original music;
  A second audio pack which is a component of the bonus music;
  Each index comprising the first and second audio packs, and
  Each composed of each indexTrack,
  Each track is composed of eachEach audio content block,
  If the data to be compared with the data supplied to the user to access the bonus music during playback is the same as the supplied data, the bonus music is Interactive data that allows playback,
  Search information for the playback device to search for the bonus music,
  The playback devicetruckSearch information for searching
  A step of encoding, modulating and recording with a predetermined format including at least:Digital audio discs recorded by.
  2) A method for reproducing a digital audio disc according to claim 1,
  A step of identifying a disk based on the disk identifier;
  A step of accepting interactive data for accessing the bonus music when identified as the digital audio disc;
  The one or more original music pieces are reproduced irrespective of the input interactive data, and when the input interactive data matches the interactive data recorded on the disc, the bonus is reproduced. The step of playing the song,
  A digital audio disc playback method comprising:
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. 1 is a block diagram showing an embodiment of a DVD enhanced audio disk encoding apparatus applied to the present invention, FIG. 2 is a block diagram showing in detail the signal processing circuit of FIG. 1, and FIG. 3 is an A / D of FIG. FIG. 4 is an explanatory diagram showing the format of user data processed by the signal processing circuit of FIG. 2, and FIG. 5 is a DVD encoding circuit of FIG. It is explanatory drawing which shows the format of the audio pack formatted, a video pack, and a program pack.
FIG. 6 is an explanatory diagram showing the format of the lead-in area and data area of a DVD enhanced audio disc applied to the present invention, FIG. 7 is an explanatory diagram showing in detail the format of the control data block of FIG. 6, and FIG. FIG. 9 is an explanatory diagram showing in detail the format of the physical format information, FIG. 9 is an explanatory diagram showing the DVD video format and the DVD-enhanced audio format formatted by the DVD encoding circuit of FIG. 1, and FIG. FIG. 11 is an explanatory diagram showing in detail the audio control (A-CONT) pack of FIG. 10, and FIG. 12 is an audio search in the A-CONT pack of FIG. Detailed data (ASD) It is a bright view.
FIG. 13 is a block diagram showing an embodiment of a DVD enhanced audio disk decoding device applied to the present invention, FIG. 14 is a flowchart for explaining disk identification processing and program reading processing of the control unit in FIG. Is a block diagram showing in detail the signal processing circuit of FIG. 13, FIG. 16 is an explanatory diagram showing the processing of the signal processing circuit of FIG. 15, and FIG. 17 is a flowchart for explaining the reproduction processing of the control unit of FIG.
[0007]
Next, the configuration of the encoder will be described in detail with reference to FIG. An analog audio signal is input to the input terminal IN, and this input signal is sampled by the A / D converter 31 at a sufficiently high sampling frequency (sampling period Δt shown in FIG. 3), for example, 192 kHz, for example, 24-bit high resolution PCM. A data string converted into a signal and corresponding to the curve α as shown in FIG.
xb1, x1, xa1, x2, xb2, x3, xa2,
..., xbi, x2i-1, xai, x2i, ...
Is converted to
[0008]
This data string (xbi, x2i-1, xai, x2i) is encoded by the signal processing circuit 32 and the memory 33 shown in detail in FIG. 2, and then packed by the DVD encoding circuit 34 in the DVD enhanced audio format. The packing data is output to the output terminal OUT1, or is modulated by the modulation circuit 35 by a modulation method corresponding to the medium and output to the output terminal OUT2.
[0009]
The configuration of the signal processing circuit 32 will be described in detail with reference to FIG. First, the band-limited curve β is changed from the data string (xbi, x2i-1, xai, x2i) corresponding to the curve α shown in FIG. Corresponding data column
xc1, *, *, *, xc2, *, *, *, xc3, *, *, *, ..., xci,
*, *, *, ...
Next, the data “*” in this data string is thinned out by the thinning circuit 37 to obtain the data string.
xc1, xc2, xc3, ..., xci, ...
Is generated. Here, the data string xci is a data string in which the sampling frequency is reduced to ¼ by limiting the band of the digital data A / D converted by the A / D converter 31. Further, the data string is obtained by thinning out the data xi from the data string (xbi, x2i-1, xai, x2i) by the thinning circuit 38.
xb1, xa1, xb2, xa2, ..., xbi, xai, ...
Is generated.
[0010]
Then, based on these data strings xci, xbi, and xai, an adder 39 acting as a difference calculator makes a difference.
xbi-xci = Δ1i
xai-xci = Δ2i
Is calculated. Here, the difference data Δ1i and Δ2i is, for example, 24 bits or less, and the number of bits may be fixed or variable. The allocation circuit 40 packs the data string xci and the difference data Δ1i and Δ2i into user data in the format shown in FIG. 4 (1 packet = 2304 bytes), and outputs the user data to the DVD encoding circuit 34.
[0011]
As shown in FIG. 5, the DVD encoding circuit 34 has 4-byte pack start information, 6-byte SCR (System Clock Reference) information, and user data of 2034 bytes per packet. An audio (A) pack is constructed by adding a pack header of 14 bytes in total of 3 bytes Mux rate information and 1 byte of stuffing (1 pack = 2048 bytes in total). In the case of a V pack, video signals and data are arranged in the user data area. In the user data area of the program (P) pack, bonus information described later and a program for playing music for each group are arranged.
[0012]
In this case, the time of the A pack in the same album can be managed by setting the SCR information, which is a time stamp, as “1” in the first pack in the ACB unit and continuing in the same album. Further, A packs can be grouped by numbering each group as SCR information.
[0013]
The DVD encoding circuit 34 also performs formatting for recording various data in the lead-in area and data area of a DVD-enhanced audio disc as shown in FIG. Here, the lead-in area of the DVD is an all 00h block from the start of the lead-in to the sector number “02F000h” and a reference code block of two blocks from the sector number “02F000h” to the sector number “02F020h”. And all 00h blocks for 30 blocks from the sector number “02F020h” to the sector number “02F200h”, and control data blocks for 192 blocks from the sector number “02F200h” to the sector number “02FE00h” , It is composed of 32 blocks of all 00h blocks from the sector number “02FE00h” to the sector number “030000h”.
[0014]
From the beginning of the data area (sector number “030000h”), ISO 9660 and micro UDF (Universal Disc Format) data are recorded, and then an audio title set (TS), video TS, computer TS, and the like are recorded. The ISO9660 and the micro UDF describe whether the directory structure of the disc is “computer program”, “video”, “audio”, or “enhanced audio” of the DVD-ROM. A disc identifier indicating “enhanced audio” is described.
[0015]
As shown in FIG. 7, the control data block in the lead-in area is composed of a sector for physical format information, a sector for disc manufacturing information, and a sector for copyright information. As shown in FIG. 8, the physical format information sector includes a book type and part version area, a disc size and minimum lead-out area, a disc structure area, a recording density area, and a data area. It consists of allocation areas.
[0016]
The book type is assigned 4 bits as a disc identifier, and indicates “DVD-ROM disc”, “DVD-RAM disc”, or “DVD-Write Once disc”. A disc identifier indicating “DVD-ROM” is described in the disc according to the present invention. Therefore, in combination with this book type, ISO9660 and micro UDF shown in FIG. 6, a disc identifier indicating “DVD-ROM-enhanced audio” is described in the disc applied to the present invention.
[0017]
In addition to the main music source for the DVD-ROM-enhanced audio disc, the DVD encoding circuit 34 also includes karaoke information (signal format is music + video), BGM signal (signal format is music), MIDI code ( In order to record data (signal format is data) and quiz data (signal format is data), recording information is packed in a format as shown in FIG. 9B.
[0018]
FIGS. 9A and 9B show the respective formats of DVD-video and DVD-enhanced audio applied to the present invention. The format of DVD-enhanced audio is compatible with DVD-video although the area names are different. Have First of all, the DVD-video format is composed of the top video manager (VMG) and each of the subsequent video title set (VTS) areas, while the DVD-enhanced audio format corresponds to this. Each area includes an audio manager (AMG) and a plurality of audio album sets (AAS) following AMG.
[0019]
Each VTS is composed of a head VTS information (VTSI), followed by one or more video content block sets (VCBS) and a last VTSI, while each AAS corresponds to the head AAS information (AASI). ) Followed by one or more audio content block sets (ACBS) and the last AASI. In AASI, the performance time of each song in the ACBS is set in real time.
[0020]
Each VCBS is composed of a plurality of VCBs, while each ACBS is composed of a plurality of ACBs. Each VCB corresponds to one title (Title) of video, and each ACB corresponds to one album (Album) of audio correspondingly. Each VCB (one title) is composed of a plurality of chapters (Chapter), while each ACB (one album) is composed of a plurality of tracks (Tracks). The chapter includes a part of title (PTT), and the track includes a part of album (PTA).
[0021]
Each chapter is composed of a plurality of cells (CELL), while each track is composed of a plurality of indexes (Index). Each cell is composed of a plurality of VCB units (VCBU), while each index is composed of a plurality of ACB units (ACBU) corresponding thereto. Each of the VCB unit and the ACB unit is composed of a plurality of packs, and one pack is composed of 2048 bytes.
[0022]
Each VCB unit is composed of a leading control pack (hereinafter referred to as a CONT pack), followed by a plurality of video (V) packs, audio (A) packs, and sub-picture (SP) packs. Corresponding to this, as shown in FIG. 10, a head audio control pack (hereinafter referred to as A-CONT pack), followed by a plurality of A packs and V packs, and further a program (P) pack.
[0023]
Information for controlling the subsequent V pack is arranged in the CONT pack, and information for managing the audio signal of the subsequent A pack and the computer program of the P pack is arranged in the A-CONT pack like the TOC information of the CD. Is done. In addition to the original music, audio data such as karaoke music and BGM is arranged in the user data area of the A pack as bonus information and information for each group, and video data such as karaoke video is stored in the user data area of the V pack. Other than the audio data, for example, karaoke super subtitles, MIDI codes, quiz data, and the like are arranged. In the user data area of the P pack, a personal identification number for reproducing bonus information and a computer program for reproducing music in groups are arranged.
[0024]
As shown in FIG. 11, the A-CONT pack is composed of a 14-byte pack header, a 24-byte system header, a 1003-byte ACD (audio character display) packet, and a 1007-byte ASD (audio search data) packet. Has been. The ACD packet includes a 6-byte packet header, a 1-byte substream ID, 636-byte ACD (audio character display) information, and a 360-byte reserved area. The ASD packet is similarly composed of a 6-byte packet header, a 1-byte substream ID, and a 1000-byte ASD (audio search data) as shown in detail in FIG.
[0025]
As shown in FIG. 12, ASD (audio search data) includes 16-byte general information, 8-byte current number information, 16-byte current time information, 8-byte album set search information, and 8-byte album information. It consists of album search information, 404-byte track search information, 408-byte index search information, 80-byte highlight search information for searching bonus information, and a 52-byte reserved area.
[0026]
When recording bonus information for the original music signal recorded in the A pack in such a format, for example, when arranging the karaoke information, the music signal is arranged adjacent to the A pack of the original music signal. A method of recording the character data for karaoke on the pack and recording the character data on the V pack which is also arranged adjacent to each other is conceivable. Further, the BGM signal, the practice sound at the time of recording, and the like are recorded in the A pack arranged adjacent to the A pack of the original music signal. The MIDI code of the original music signal is recorded in the V pack.
[0027]
When reproducing such bonus information, a player dedicated to DVD-ROM enhanced audio discs (or a compatible device with other discs) as shown in FIG. 13 is used. The user who purchased the disc can play the original music signal free of charge, but for the bonus information, the user has to pay an appropriate price and enter the personal identification number. As another usage method, there may be a usage mode in which a quiz program is stored free of charge, displayed on the decoder side, and bonus information is reproduced when a correct answer is input. In addition, in the case of a disc in which a reproduction program for dividing music into groups and reproducing each group is recorded in a P pack, the user pays for each reproduction program or inputs a personal identification number for free To do.
[0028]
Next, the decoder will be described with reference to FIG. The signal read from the digital audio disk is first demodulated by the demodulation circuit 41 in accordance with the modulation method of the modulation circuit 35 on the encoder side, and then the data in the lead-in area, A-CONT pack, A pack, Separated into V pack, P pack and the like. Based on the data in the lead-in area, the control unit 63 performs disk identification processing and program reading processing as shown in FIG. 14 as initial processing.
[0029]
First, the book type shown in FIG. 8 is read (step S11), and it is determined whether or not the book type is “DVD-ROM” (step S12). If YES, the process proceeds to step S13 and thereafter. If NO, The process ends. In step S13, the ISO9660 / micro UDF directory structure shown in FIG. 6 is read, and then it is determined whether or not it is “enhanced audio” (step S14). If YES, the process proceeds to step S15 and subsequent steps. Exit. In step S15, the program is identified and read by looking at the program title in the enhanced audio TS shown in FIG. 6, and then this program is activated (step S16).
[0030]
In FIG. 13, the user data (data string xci and difference data Δ1i, Δ2i) in the A pack separated by the DVD decoding circuit 42 is applied to the stream output terminal 52 via the switch 51 and is described in detail in FIG. The signal processing circuit 43 (and the memory 44) shown in FIG. The video data in the V pack is output to an external display via the video processor 48 and the video output terminal 64, and the MIDI code is output to an external electronic musical instrument via the MIDI processor 49a and the MIDI output terminal 65.
[0031]
In the signal processing circuit 43, as shown in FIG.
Δ1i + xci = xbi
Δ2i + xci = xai
Is calculated, and the data strings xbi and xai are restored. Here, the data strings xbi and xai are the original 24 bits.
[0032]
Next, the interpolation processing circuit 47 interpolates the data string xi between them using a plurality of data of the data strings xbi and xai as shown in FIG. Note that the interpolation processing circuit 47 can obtain the interpolation data string xi by using, for example, an upsampling method, filling each of them with zero data and passing through a low-pass filter. The interpolation data string xi may also be obtained by curve approximation or prediction approximation. In this case, the degree of approximation can be increased by adding approximate auxiliary data for transmission.
[0033]
Data interpolated in this way is
xb1, x1, xa1, x2, xb2, x3, xa2,
..., xbi, x2i-1, xai, x2i, ...
The audio PCM signal is applied to a D / A converter 45 and an LPF (low-pass filter) 56 shown in FIG.
[0034]
In the D / A converter 45, the encoder side performs A / D conversion with the number of quantization bits of 24 bits, and therefore, the data string (xbi) encoded and recorded on the recording medium and processed by the signal processing circuit 43 on the decoder side. , X2i-1, xai, x2i) is converted into an analog audio signal at a sampling frequency of 192 kHz and output via the analog output terminal 55. In the LPF 56, the input data is limited to a quarter band (48 kHz), for example, and output as digital audio data via the output terminal 53.
[0035]
In this embodiment, the bit stream (data string xci and difference data Δ1i, Δ2i) transmitted through the medium can be output as it is through the switch 51 and the bitstream output terminal 52, and A terminal 49 for inputting a personal identification number and outputting a copy (recording) permission signal, and a cipher for turning on the switch 51 based on the personal identification number inputted through the terminal 49 and copyright data in the subheader. A decrypting unit 50 is provided. The cryptanalysis unit 50 includes an authentication function for determining the authenticity of the password.
[0036]
When a code number is input, the decryption unit 50 receives an authentication check, and when it is authenticated as authentic, it checks a copy permission condition in the copyright data in the subheader, for example, “payment condition”. In the case of OK, the bit stream copy is permitted by turning on the switch 51.
[0037]
In addition, as the operation unit 62, for example, a playback location can be designated by an interactive input signal from a computer keyboard, or a quiz program can be displayed on the display unit 61 to input a correct answer via the operation unit 62. In this case, it can be output without band limitation or band limitation, and suitable audio and video can be selected from multiple scenes and played as a stream (highlighted). Also good.
[0038]
Next, the reproduction process of the control unit 63 will be described with reference to FIG. If the bonus computer program is selected in step S1, the process proceeds to step S2, and otherwise the process proceeds to step S5. In step S2, the input of a personal identification number is awaited, and it is determined whether the personal identification number is correct (step S3). If it is correct, the process proceeds to step S4, and if not correct, the process proceeds to step S5. In step S4, a bonus computer program is selected and loaded (step S4), and then reproduction according to the instruction is performed (step S5).
[0039]
Here, the computer program may be arranged in a P pack and mixed with the A pack of the original music piece, but may instead be recorded on a specific track of the disc. For example, as shown in FIG. 18, the disk is divided into a lead-in area 7a, data areas 7b and 7e, and a lead-out area 7f from the inner circumference to the outer circumference in the radial direction D, and the data area 7b on the inner circumference side. May be recorded with a computer program, and music information or the like may be recorded in the outer data area 7e. In this case, the computer program track will only be entered if the correct password has been entered, or if the correct answer has been obtained in the quiz question for the built-in computer program. Access and play. Further, playback may be performed based on highlight search information recorded in the ASD shown in FIG.
[0040]
19 and 20 show a playback player and a playback method according to another embodiment. The playback device 100 shown in FIG. 19 has the same configuration as the decoder shown in FIG. 13, and a card reader 101 for reading data of the card-type electronic money 102 is connected to the control unit 63 in the playback device 100. Yes. Then, as shown in FIG. 20, when the playback button of the operation unit 62 is pressed (step S21), the control unit 63 charges a playback fee for the card-type electronic money 102 (step S22), and then performs playback (step S22). Step S23).
[0041]
The software recorded on the DVD-ROM-enhanced audio disc provided by the present invention described above is
A. Bonus information (bonus music)
B. Other purpose programs (karaoke playback programs, etc.)
C. Bonus program
And the area where the programs B and C are recorded is
a. P pack
b. Program area of data area 7b
It is.
[0042]
When these are combined, there are the following 10 methods.
(1) A + a (there is one program, and bonus information A is reproduced with pay or quiz correct answer)
(2) A + b (there is one program and the bonus information A is reproduced with a pay or quiz correct answer)
(3) B + a (program is 2 or more, one is selected and used as another disc software (karaoke software, etc.))
(4) B + b (two or more programs are selected, and one is selected and used as another disc software)
(5) A + B + a (The program is in a P pack and is 2 or more, and when one is selected, it is used as another disc software. Bonus information A is reproduced with a pay or quiz correct answer)
(6) A + B + b (The program is in the program area and there are two or more, and when one is selected, it is used as another disc software. Also, bonus information A is reproduced with pay or quiz correct answer)
(7) C + a (there is basically one program, but another program can be selected as a bonus and used as another disc software)
(8) C + b (there is basically one program, but another program can be selected as a bonus and used as another disc software)
(9) A + C + a (The program is basically one in the P pack, but another program can be selected as a bonus and used as another disc software. Also, bonus information A can be paid or quized. Play with the correct answer)
(10) A + C + b (the program is basically one in the program area, but another program can be selected as a bonus and used as another disc software. Further, the bonus information A is paid or quized. Play with the correct answer.
[0043]
【The invention's effect】
As described above, according to the present invention, one or more music pieces, bonus information related to the music pieces, interactive data for accessing the bonus information, and a disc identifier are recorded on the digital audio disc, and the disc identifier is recorded on the playback side. If it is determined whether or not to accept the input of interactive data based on that, and if it is determined to accept, bonus information playback is permitted when correct interactive data is input. For example, the original music and the music Data such as karaoke, BGM, MIDI, and practice voice at the time of recording are recorded as bonus information on the original, and the original music is allowed to be played for free, but the bonus information is interactive with the PIN number obtained by the user for payment. Allow playback when entered as data So that mode of use is considered, therefore, the user can perform a wide variety of playback, also it can be disk manufacturer to use the same disc in a different way.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of a DVD enhanced audio disk encoding apparatus applied to the present invention.
FIG. 2 is a block diagram showing in detail the signal processing circuit of FIG. 1;
3 is an explanatory diagram showing a sampling period and an A / D conversion data string of the A / D converter of FIG. 1. FIG.
4 is an explanatory diagram showing a format of user data processed by the signal processing circuit of FIG. 2; FIG.
FIG. 5 is an explanatory diagram showing formats of an audio pack, a video pack, and a program pack that are formatted by the DVD encoding circuit of FIG. 1;
FIG. 6 is an explanatory diagram showing a format of a lead-in area and a data area of a DVD enhanced audio disk applied to the present invention.
7 is an explanatory diagram showing in detail the format of the control data block of FIG. 6; FIG.
FIG. 8 is an explanatory diagram showing in detail the format of the physical format information in FIG. 7;
9 is an explanatory diagram showing a DVD video format and a DVD-enhanced audio format formatted by the DVD encoding circuit of FIG. 1; FIG.
10 is an explanatory diagram showing in detail the audio content block unit (ACBU) of FIG. 9;
FIG. 11 is an explanatory diagram showing in detail the audio control (A-CONT) pack of FIG. 10;
12 is an explanatory diagram showing in detail audio search data (ASD) in the A-CONT pack of FIG. 11. FIG.
FIG. 13 is a block diagram showing an embodiment of a DVD enhanced audio disk decoding device applied to the present invention.
14 is a flowchart for explaining disk identification processing and program read processing of the control unit in FIG. 13;
15 is a block diagram showing in detail the signal processing circuit of FIG. 13;
16 is an explanatory diagram showing processing of the signal processing circuit of FIG. 15;
FIG. 17 is a flowchart for explaining a reproduction process of the control unit in FIG. 13;
FIG. 18 is an explanatory diagram showing another example of a program area.
FIG. 19 is a block diagram showing a playback player of another embodiment.
20 is a flowchart for explaining a reproduction process of the embodiment shown in FIG.
[Explanation of symbols]
31 A / D converter (A / D conversion means)
34 DVD encoding circuit (recording means)
62 Operation section (input means)
63 Control unit (determination means, reproduction means)

Claims (2)

When recording to a digital audio disc, an analog audio signal of one or more original music pieces and a bonus music piece for selective reproduction separately from the original music piece is A / D converted at a sampling frequency higher than 96 kHz. A step of generating a digital data sequence,
The auxiliary signal recording area and the main signal recording area are continuously arranged, and include at least a disk identifier for identifying the disk in the auxiliary signal recording area, and in the main signal recording area,
1 or more the original music, the volume for playing separately selectively the original music - the Deiomanejiya (AMG), - the eggplant music, manage O
A first audio pack which is a component of the original music;
A second audio pack which is a component of the bonus music;
Each index comprising the first and second audio packs, and
Each track composed of each index, and
Each audio content block composed of each track ,
If the data to be compared with the data supplied to the user to access the bonus music during playback is the same as the supplied data, the bonus music is Interactive data that allows playback,
Search information for the playback device to search for the bonus music,
Search information for the playback device to search the track of the original music,
A digital audio disk recorded by a step of encoding, modulating and recording with a predetermined format including at least A method of reproducing a digital audio disc according to claim 1,
Identifying a disk based on the disk identifier;
A step of accepting interactive data for accessing the bonus music when identified as the digital audio disc;
The one or more original music pieces are reproduced irrespective of the input interactive data, and when the input interactive data matches the interactive data recorded on the disc, the bonus is reproduced. The step of playing the song,
A digital audio disc playback method comprising:

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