Was is Redbook??
Redbook?
Maximilian fragt: What is Redbook?
The Red Book
In June of 1980, Phillips and Sony released the "red book" specification on Compact Disc Digital Audio System, and was adopted by the Digital Audio Disc Committee. It was later ratified as the IEC 908 standard for digital audio on compact discs.
The IEC 908 standard primarily specifies the layout and data structure of the information area of the disc, which begins at the groove 46 mm from the center of the disc, extending to 117 mm at the edge of the disc.
Each IEC 908 Red Book CD stores data in sectors of 2352 bytes each. Each sector contains exactly 1/75-th second of 16 bit stereo audio sampled at 44.1 KHz stored as two's complement Pulse Code Modulated (PCM) data. To see how this comes about, please note that each monaural audio channel takes up 44,100*16 = 705,600 bits or 88,200 bytes of data per second. For stereo, it is 176,400 bytes per second, yielding 176,400/75 = 2352 bytes per 1/75-second.
Please note that the 2352 bytes are after reading the raw data from CD, then apply EFM demodulation and CIRC error correction, and are NOT what are actually on the disc physically. That is, the 2352 byte sector, when written to the disc, gets bigger as the subcodes are added (explained later), Reed Soloman CIRC error correction is applied, then 8 to 14 EMF modulated. Also, each sector is actually subdivided into into 98 clusters of 6 stereo samples each.
Beginning at 46 mm from center, the information area beings with what is known as the "lead-in", which extends to 50 mm from center. The lead-in, contains among other things, the Table of Contents (TOC), which specifies the data type (data or audio), starting time, logical block address (LBA), and length of each track (up to 99 tracks are allowed).
After the lead-in comes the program area, where the data resides.
According to the IEC 908 specification, all Red Book compliant discs must start the program area with a "pre-gap", or 150 sectors (2 seconds) of blank data.
After the pre-gap, comes the data. For IEC 908 discs, this will be raw sectors of 2352 bytes each, holding PCM audio data in two's complement. Under the Yellow Book standard for CD-ROM as introduced in 1984, other types of data and sector formatting are allowed.
Along with each sector is stored 98 clusters of 8 bit blocks of subcode data. The 8 bits from each block of subcode is named P, Q, R, S, T, U, V, and W--in that order. The first two bits, P and Q, indicates what part of the disc is being read, start and end times, as well as other play time information. Bits R throu gh W are primarily used in CD+G (karokee CDs). PQ subcodes basically control the pauses between tracks, or the data that lies between index 0 and 1. By default, there must be 150 sectors (2 seconds) of gap between each track, however, by editing the PQ subcodes, one can decrease this to 0.
After the program area is the lead-out, or 6750 blank sectors.
In 1988, the Orange Book specification (Was this ratified by the IEC? If so, what's the number?) for CD-WO (CD Write Once), or CD-R (CD Recordable) was released. The Orange Book specification added two extra areas to the CD (Can anyone tell me WHERE they're located PHYSICALLY?), named the Power Calibration Area (PCA) and the Program Memory Area (PMA). The PCA is used by the CD-R writer to calibrate the power of the laser on it each time the disc is to be written to (up to 99 times, since a maximum of 99 tracks are allowed). The PMA holds the temporary TOC until the permanent TOC is fixated.
There are three ways to write an audio CD (only one of which is IEC 908 compliant). They're Disc At Once (DAO), Track At Once (TAO), and what can be best explained as multiple tracks at once.
DAO is simply the process of writing the entire disc from inner to outer rim, without shutting off the laser at any time during this process. To accomplish this, one must have the TOC as well as the entire program area stored (typically on one's hard disk ) prior to writing. This is because the TOC is located at 46 to 50 mm from center, which is in front of the program area. Therefore, a TOC, or a file representing the TOC, such as a cue sheet, must be edited and passed along to the burner prior to writing, allowing the burner to write the TOC (padded with blank data until 50 mm), then write the 150 sector pre-gap, followed by the audio. The burner can either be a general purpose computer with an attached burner or a special purpose stand-alone unit contai ning hard drive, display, and its own keypad (note that these units are typically advertised in the back of Replication News as stand-alone replicators). (Greg Hanssen of ZA tells me that there is also a company producing a stand-alone unit with a built-in OEM version of the ZA2 audio card that can be used to produce DAO mode audio CD-Rs.)
TAO is simple, write each track and then shut off the laser. After all tracks are written, fixate the disc by appending a lead-out and then, shut off the laser, moves it from up to 117 mm from center to 46 mm from center and write the TOC. The disc written in this manner is not an IEC 908 compliant disc, though it does play in most (nearly all) post 1988 CD players. The reason for this is simple, there is no proper transition from the lead-in to the pre-gap, no proper transition between each track (though the 150 sector padding between tracks are satisfied), and no proper transition between the program area and lead-out. Most annoyingly of all, as one cannot edit the PQ subcode in TAO mode, one suffer from the 150 sector gap between tracks, making the TAO mode unusa ble in any circumstance where the audio is to seamlessly extend across multiple tracks.
The last method, or what I call the multi-track at once method, is the one used by stand-alone audio CD-R recorders. Basically, this is like the TAO mode above except that the unit does allow you to avoid putting an 150 sector gap between tracks. However, all other points of TAO mode apply, including the lack of proper transitions between TOC and pre-gap as well as the audio data and the lead-out. While the laser does not have to be turned off during the entire writing of the program area (unlike true TAO above), this method still has to shut off the laser after the lead-out to make the necessary journey from up to 177 mm back to 46 mm from center as to fixate the disc (i.e., burn the TOC).
Of the above three modes, only DAO can create a CD-R that fully satisfies the requirement of IEC 908. The latter two modes can only claim to create a Red Book compatible audio CD, but not one that is fully compliant. (This is kind of like claiming that Linux is not UNIX, but is only UNIX compatible, since Linux is not based on SVR4 derivative code.)
The Red Book
In June of 1980, Phillips and Sony released the "red book" specification on Compact Disc Digital Audio System, and was adopted by the Digital Audio Disc Committee. It was later ratified as the IEC 908 standard for digital audio on compact discs.
The IEC 908 standard primarily specifies the layout and data structure of the information area of the disc, which begins at the groove 46 mm from the center of the disc, extending to 117 mm at the edge of the disc.
Each IEC 908 Red Book CD stores data in sectors of 2352 bytes each. Each sector contains exactly 1/75-th second of 16 bit stereo audio sampled at 44.1 KHz stored as two's complement Pulse Code Modulated (PCM) data. To see how this comes about, please note that each monaural audio channel takes up 44,100*16 = 705,600 bits or 88,200 bytes of data per second. For stereo, it is 176,400 bytes per second, yielding 176,400/75 = 2352 bytes per 1/75-second.
Please note that the 2352 bytes are after reading the raw data from CD, then apply EFM demodulation and CIRC error correction, and are NOT what are actually on the disc physically. That is, the 2352 byte sector, when written to the disc, gets bigger as the subcodes are added (explained later), Reed Soloman CIRC error correction is applied, then 8 to 14 EMF modulated. Also, each sector is actually subdivided into into 98 clusters of 6 stereo samples each.
Beginning at 46 mm from center, the information area beings with what is known as the "lead-in", which extends to 50 mm from center. The lead-in, contains among other things, the Table of Contents (TOC), which specifies the data type (data or audio), starting time, logical block address (LBA), and length of each track (up to 99 tracks are allowed).
After the lead-in comes the program area, where the data resides.
According to the IEC 908 specification, all Red Book compliant discs must start the program area with a "pre-gap", or 150 sectors (2 seconds) of blank data.
After the pre-gap, comes the data. For IEC 908 discs, this will be raw sectors of 2352 bytes each, holding PCM audio data in two's complement. Under the Yellow Book standard for CD-ROM as introduced in 1984, other types of data and sector formatting are allowed.
Along with each sector is stored 98 clusters of 8 bit blocks of subcode data. The 8 bits from each block of subcode is named P, Q, R, S, T, U, V, and W--in that order. The first two bits, P and Q, indicates what part of the disc is being read, start and end times, as well as other play time information. Bits R throu gh W are primarily used in CD+G (karokee CDs). PQ subcodes basically control the pauses between tracks, or the data that lies between index 0 and 1. By default, there must be 150 sectors (2 seconds) of gap between each track, however, by editing the PQ subcodes, one can decrease this to 0.
After the program area is the lead-out, or 6750 blank sectors.
In 1988, the Orange Book specification (Was this ratified by the IEC? If so, what's the number?) for CD-WO (CD Write Once), or CD-R (CD Recordable) was released. The Orange Book specification added two extra areas to the CD (Can anyone tell me WHERE they're located PHYSICALLY?), named the Power Calibration Area (PCA) and the Program Memory Area (PMA). The PCA is used by the CD-R writer to calibrate the power of the laser on it each time the disc is to be written to (up to 99 times, since a maximum of 99 tracks are allowed). The PMA holds the temporary TOC until the permanent TOC is fixated.
There are three ways to write an audio CD (only one of which is IEC 908 compliant). They're Disc At Once (DAO), Track At Once (TAO), and what can be best explained as multiple tracks at once.
DAO is simply the process of writing the entire disc from inner to outer rim, without shutting off the laser at any time during this process. To accomplish this, one must have the TOC as well as the entire program area stored (typically on one's hard disk ) prior to writing. This is because the TOC is located at 46 to 50 mm from center, which is in front of the program area. Therefore, a TOC, or a file representing the TOC, such as a cue sheet, must be edited and passed along to the burner prior to writing, allowing the burner to write the TOC (padded with blank data until 50 mm), then write the 150 sector pre-gap, followed by the audio. The burner can either be a general purpose computer with an attached burner or a special purpose stand-alone unit contai ning hard drive, display, and its own keypad (note that these units are typically advertised in the back of Replication News as stand-alone replicators). (Greg Hanssen of ZA tells me that there is also a company producing a stand-alone unit with a built-in OEM version of the ZA2 audio card that can be used to produce DAO mode audio CD-Rs.)
TAO is simple, write each track and then shut off the laser. After all tracks are written, fixate the disc by appending a lead-out and then, shut off the laser, moves it from up to 117 mm from center to 46 mm from center and write the TOC. The disc written in this manner is not an IEC 908 compliant disc, though it does play in most (nearly all) post 1988 CD players. The reason for this is simple, there is no proper transition from the lead-in to the pre-gap, no proper transition between each track (though the 150 sector padding between tracks are satisfied), and no proper transition between the program area and lead-out. Most annoyingly of all, as one cannot edit the PQ subcode in TAO mode, one suffer from the 150 sector gap between tracks, making the TAO mode unusa ble in any circumstance where the audio is to seamlessly extend across multiple tracks.
The last method, or what I call the multi-track at once method, is the one used by stand-alone audio CD-R recorders. Basically, this is like the TAO mode above except that the unit does allow you to avoid putting an 150 sector gap between tracks. However, all other points of TAO mode apply, including the lack of proper transitions between TOC and pre-gap as well as the audio data and the lead-out. While the laser does not have to be turned off during the entire writing of the program area (unlike true TAO above), this method still has to shut off the laser after the lead-out to make the necessary journey from up to 177 mm back to 46 mm from center as to fixate the disc (i.e., burn the TOC).
Of the above three modes, only DAO can create a CD-R that fully satisfies the requirement of IEC 908. The latter two modes can only claim to create a Red Book compatible audio CD, but not one that is fully compliant. (This is kind of like claiming that Linux is not UNIX, but is only UNIX compatible, since Linux is not based on SVR4 derivative code.)
Hallo Art,
da ebs Dir hier wirklich extrem fachkompetent und emotionslos sachlich geantwortet hat, würde sagen, daß Du den Idioten unter diesen Umständen zurücknehmen solltest, oder?
Martin
Zur Erinnerung
da ebs Dir hier wirklich extrem fachkompetent und emotionslos sachlich geantwortet hat, würde sagen, daß Du den Idioten unter diesen Umständen zurücknehmen solltest, oder?
Martin
Zur Erinnerung
Hallo Art,Mit solchen Forderungen wirst du bei den betreffenden Leuten leider gegen den Baum fahren. Wenn der Mr. Art es nicht verstanden hat, was ebs versuchte, ihm mit seinem Posting klarzumachen hat er leider Pech. Ich für meinen Teil habe mich köstlich über ebs Antwort amüsiert, Mr. Art anscheinend nicht, naja. Und ich glaube auch nicht, dass das "Idiot" ernstgenommen wird, er wusste halt nicht, wen er da gerade beschimpft hat (was jetzt wohl immer noch der Fall sein wird).
da ebs Dir hier wirklich extrem fachkompetent und emotionslos sachlich geantwortet hat, würde sagen, daß Du den Idioten unter diesen Umständen zurücknehmen solltest, oder?
Martin
mfg
Hallo Martin,
Ich habe das auch gelesen. Ich würde mich aber darüber nicht verrückt machen, denn mit solchen Titulierungen disqualifiziert sich der Poster doch nur selbst. Wenn ihn dann ebs und andere auflaufen lassen wird es's schon merken.
Grüße
Rainer
Ich habe das auch gelesen. Ich würde mich aber darüber nicht verrückt machen, denn mit solchen Titulierungen disqualifiziert sich der Poster doch nur selbst. Wenn ihn dann ebs und andere auflaufen lassen wird es's schon merken.
Grüße
Rainer
Hallo Art,Mit solchen Forderungen wirst du bei den betreffenden Leuten leider gegen den Baum fahren. Wenn der Mr. Art es nicht verstanden hat, was ebs versuchte, ihm mit seinem Posting klarzumachen hat er leider Pech. Ich für meinen Teil habe mich köstlich über ebs Antwort amüsiert, Mr. Art anscheinend nicht, naja. Und ich glaube auch nicht, dass das "Idiot" ernstgenommen wird, er wusste halt nicht, wen er da gerade beschimpft hat (was jetzt wohl immer noch der Fall sein wird).
da ebs Dir hier wirklich extrem fachkompetent und emotionslos sachlich geantwortet hat, würde sagen, daß Du den Idioten unter diesen Umständen zurücknehmen solltest, oder?
Martin
mfg