Hi. Anybody knows, what these AG# numbers in the id3 comment field (COMM) are ?
for example:
COMMENT: , AG# 8F62B817
looks like some checksum to me, but I ran a CRC32 hash on my files (both on the whole file and on the audio part only!) and the values don't match. So it's either another hash-function or something unrelated ....
Does anybody know, which applications write that and what it means ?
Thanks a lot!
Full Version: What are these AG# numbers in the id3 comment field ?
It's nothing you're likely to see in a legal download. 
Even of 'Satellite of Love' ?
It means the file has created using AudioGrabber, the number I'm not sure if it is disc ID or checksum
If the OP is using AudioGrabber I've got some egg on my face. 
i guess he had the mp3 file from p2p. fortunately, i'm not the OP, or you'd really get some egg on your face... i still use AudioGrabber!
I think this isn't AudioGrabber. IIRC AudioGalaxy used that many years ago (2000/2001?)
But nothing legal though...
But nothing legal though...
I think it is AudioCatalyst 
.
.
Well, It could also be AudioCatalyst, since it is a modified version of AudioGrabber, only with the Xing encoder. The "AG# 8F62B817" is the checksum of the ripped CD track, included in the ID3 tag when the "Append checksum to comment field" box is checked. Much as the OP ran the file into CRC checking, he would not get the same checksum value. The said checksum is just used to "test and compare" the rips if indeed AudioGrabber ripped the track accurately (or precisely would be a better term).
It cannot be due to AudioGalaxy, although it appears to be an acronym of it. It appears, though, that the mp3 file in question is downloaded from an illegal p2p network, since the OP has no idea what the comment was (and he isn't using AudioGrabber).
To the OP, welcome to HydrogenAudio! You can find here many experts, including from the field of ancient apps such as AudioGrabber! (and I wonder where greynol is)
It cannot be due to AudioGalaxy, although it appears to be an acronym of it. It appears, though, that the mp3 file in question is downloaded from an illegal p2p network, since the OP has no idea what the comment was (and he isn't using AudioGrabber).
To the OP, welcome to HydrogenAudio! You can find here many experts, including from the field of ancient apps such as AudioGrabber! (and I wonder where greynol is)
QUOTE(Rio @ May 11 2008, 01:55) 
(and I wonder where greynol is)
Looking for Tabasco.
Hi guys, first of all sorry for my late reply. I was not aware of your postings (e-mail notification didn't work).
Thanks for your welcome message Rio.
And thanks for the technical aspects of your answers and for your kind help!
The question I still have is:
Is it possible to identify the music track via the #number ? (i.e. can I look-up the #number in some music database on the internet, etc.) ? A bit like the MusicBrainz ID or (- more unrelated though as it's only for whole releases -) the freeDB ID number. I guess not, as the bit value of the hash is too low for that purpose. What do you know about this?
PS: I think it's consistent with board rules to stop&ban talk about illegal filesharing on this board. But my question really had nothing to do whatsoever with this. It like I post a question in a car-related forum because there is a button in my car, I have no clue of ... people in the car-forum would never accuse me of having stolen the car either, so ... (:
Please be assured, that the file in question is legit and please let's consider this point closed.
Thanks for your welcome message Rio.
And thanks for the technical aspects of your answers and for your kind help!
The question I still have is:
Is it possible to identify the music track via the #number ? (i.e. can I look-up the #number in some music database on the internet, etc.) ? A bit like the MusicBrainz ID or (- more unrelated though as it's only for whole releases -) the freeDB ID number. I guess not, as the bit value of the hash is too low for that purpose. What do you know about this?
PS: I think it's consistent with board rules to stop&ban talk about illegal filesharing on this board. But my question really had nothing to do whatsoever with this. It like I post a question in a car-related forum because there is a button in my car, I have no clue of ... people in the car-forum would never accuse me of having stolen the car either, so ... (:
Please be assured, that the file in question is legit and please let's consider this point closed.
QUOTE(chrizoo @ Jul 5 2008, 14:17)
Hi guys, first of all sorry for my late reply. I was not aware of your postings (e-mail notification didn't work).
Thanks for your welcome message Rio.
And thanks for the technical aspects of your answers and for your kind help!
The question I still have is:
Is it possible to identify the music track via the #number ? (i.e. can I look-up the #number in some music database on the internet, etc.) ? A bit like the MusicBrainz ID or (- more unrelated though as it's only for whole releases -) the freeDB ID number. I guess not, as the bit value of the hash is too low for that purpose. What do you know about this? ...
From Audiograbber's help file:
QUOTE
Calculate checksum
This function is found under the file menu.
Some CD players that actually can read digital audio do not necessarily read 100% correctly. The resultant files are then not exact copies of the originals. This can also happen if the CD is scratched, has fingerprints etc. It is hard to tell if a track is read perfectly only by listening to it. Checksums are therefor a good way to test if the CD player read 100% correctly. When a track is copied from a CD disc, Audiograbber automatically calculates a checksum. By reading the same track on two different CD players the checksums can be compared. If they are the same then the tracks are also the same and the reading is perfect.
But hey, readings do not usually start on exactly the same byte, so how can a checksum be calculated then? Yeah, a presumption for this is that the track begins and ends with silence. The checksum will then be calculated on only that part of the track that is over a value of 127.
(A sample from the CD can be between -32768 to +32767 (16 bits). -32768 means that the speaker's membrane is pulled back as much as possible, +32767 that it is pushed forward to maximum position and 0 that it is in its middle position. The more the membrane is moving back and forth the louder the speaker is playing. Samples in the interval -127 to +127 are interpreted as silence in Audiograbber. When a checksum is calculated, Audiograbber finds the first sample outside this interval. Then it finds where the file goes outside the interval for the last time and after that it starts to calculate the checksum. It does not matter if there is a bit of silence in the middle of the track, that part will also be included in the checksum.)
NOTE! If there is not enough silence (one frame = 2352 bytes) in either the beginning or the end of the track an X is added to the checksum. This indicates that other readings from the CD may give other checksums even if they are read in the same way. The checksum can not be used if it contains an X.
By comparing checksums from tracks you have grabbed with your own CD with already known and confirmed correct checksums you can test if the CD reads the way it should. There are some correct checksums on http://www.audiograbber.com-us.net/checksums.html that you can compare with if you are lucky to have some of the CD's listed. Understand that you must have a copy of the exact same CD, it is not enough to have the same song.
You can report your own checksums on http://www.audiograbber.com-us.net/checksums.html. Those tracks should then have been read at least twice on a CD player that you are sure reads digital audio correctly. Report checksums from track 1,3 and 5. When you only want the checksum and not the entire track the function test comes in handy and you don't have to save the track on the hard disk.
Compare two files is another function that controls the CD's audio reading. If two checksums are not the same the compare two files function can see where the files are different. Checksums can also be calculated on tracks that have been read by other programs.
This function is found under the file menu.
Some CD players that actually can read digital audio do not necessarily read 100% correctly. The resultant files are then not exact copies of the originals. This can also happen if the CD is scratched, has fingerprints etc. It is hard to tell if a track is read perfectly only by listening to it. Checksums are therefor a good way to test if the CD player read 100% correctly. When a track is copied from a CD disc, Audiograbber automatically calculates a checksum. By reading the same track on two different CD players the checksums can be compared. If they are the same then the tracks are also the same and the reading is perfect.
But hey, readings do not usually start on exactly the same byte, so how can a checksum be calculated then? Yeah, a presumption for this is that the track begins and ends with silence. The checksum will then be calculated on only that part of the track that is over a value of 127.
(A sample from the CD can be between -32768 to +32767 (16 bits). -32768 means that the speaker's membrane is pulled back as much as possible, +32767 that it is pushed forward to maximum position and 0 that it is in its middle position. The more the membrane is moving back and forth the louder the speaker is playing. Samples in the interval -127 to +127 are interpreted as silence in Audiograbber. When a checksum is calculated, Audiograbber finds the first sample outside this interval. Then it finds where the file goes outside the interval for the last time and after that it starts to calculate the checksum. It does not matter if there is a bit of silence in the middle of the track, that part will also be included in the checksum.)
NOTE! If there is not enough silence (one frame = 2352 bytes) in either the beginning or the end of the track an X is added to the checksum. This indicates that other readings from the CD may give other checksums even if they are read in the same way. The checksum can not be used if it contains an X.
By comparing checksums from tracks you have grabbed with your own CD with already known and confirmed correct checksums you can test if the CD reads the way it should. There are some correct checksums on http://www.audiograbber.com-us.net/checksums.html that you can compare with if you are lucky to have some of the CD's listed. Understand that you must have a copy of the exact same CD, it is not enough to have the same song.
You can report your own checksums on http://www.audiograbber.com-us.net/checksums.html. Those tracks should then have been read at least twice on a CD player that you are sure reads digital audio correctly. Report checksums from track 1,3 and 5. When you only want the checksum and not the entire track the function test comes in handy and you don't have to save the track on the hard disk.
Compare two files is another function that controls the CD's audio reading. If two checksums are not the same the compare two files function can see where the files are different. Checksums can also be calculated on tracks that have been read by other programs.
The attempt to create an online list of the checksums wasn't succesful. The list contains only a few submissions: http://www.audiograbber.com-us.net/international.html
Wow Alex B, that was SO VERY VERY helpful... thanks so much for that!
And you are right, there are really "only a few submissions" .... 42 tracks to be more precise.
not really comparable to the tens of thousands of entries in other music DBs ...
And hey, Alex B, I'm new to this forum and 3 of the 4 problems I posted here so far were answered by ... you !
So I thought I'd try my luck and ask you if you could maybe have a quick look at my last (4th) topic to see if you also know an answer this:
http://www.hydrogenaudio.org/forums/index....showtopic=62139
Thanks a lot.
And you are right, there are really "only a few submissions" .... 42 tracks to be more precise.
not really comparable to the tens of thousands of entries in other music DBs ... And hey, Alex B, I'm new to this forum and 3 of the 4 problems I posted here so far were answered by ... you !
So I thought I'd try my luck and ask you if you could maybe have a quick look at my last (4th) topic to see if you also know an answer this:
http://www.hydrogenaudio.org/forums/index....showtopic=62139
Thanks a lot.
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