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How AccurateRip does calculate the discIDs ?
Bregalad
post Feb 28 2010, 23:21
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Hi
I have some questions about the AccurateRip discIDs, I searched but didn't find anything about this

Firstly the last part of AccurateRip discID is the cddb discID, right ?

Then I suppose the rest is calculated using the TOC , but does it uses track length in seconds (as cddb) and performs a different algorithm or does it take account of more precise information for example tracks length in frames ?

Can we be sure two different albums having the same track lengths in seconds (which is highly improbable for most albums but totally possible for 2-track singles) (and which will get the same cddb discID) will have a different AccurateRip discID ?

Or taking it reverse can we be sure (or 99,9% sure) an AccurateRip discID correspond to a single existing CD ? or does it at least tell something about two such CDs ?
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Bregalad
post Mar 2 2010, 00:28
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Actually I still have questions blush.gif

Why does the first part, number of tracks, does not appear in CUETools reports ?
Is it used when asking AccurateRip database ?

I understand disc ID collisions are no problem, cool
Anyway discID collisions (I mean two totally different albums having the same ID) are almost impossible, no ?
Even with the colossal number of existing albums I believe it's almost impossible there exists two totally different CDs with the same exact TOC
Though it might be possible for CD singles I guess it is really improbable when there is at least 4 tracks or 20 min of music
And also that the probability of getting the same AccurateRip discID whereas different TOC is almost null
So an AccurateRip discID is almost surely linked to a single existing album (eventually in different pressings)
Right ?

So on this example (Protest the Hero - Fortress)
CODE
[Verification date: 28.02.2010 13:41:10]
    [Disc ID: 0010d0be-0084b66f-8b09ac0a]
    Pregap length 00:50:59.
    Track [ CRC ] Status
    01 [f1877e25] (00/24) No matches
    02 [7dd00c91] (00/23) No matches
    03 [c63dc326] (00/23) No matches
    04 [fd0d9c32] (00/23) No matches
    05 [92ff52ad] (00/23) No matches
    06 [0c4542ba] (00/24) No matches
    07 [d853bb6d] (00/23) No matches
    08 [8cdc9a98] (00/23) No matches
    09 [7c836d5d] (00/23) No matches
    10 [00b2a409] (00/23) No matches
    Offsetted by 664:
    01 [e5313db5] (04/24) Accurately ripped
    02 [b340fb51] (04/23) Accurately ripped
    03 [23a0e3bd] (04/23) Accurately ripped
    04 [a25eb750] (04/23) Accurately ripped
    05 [06b589aa] (04/23) Accurately ripped
    06 [66a8835e] (04/24) Accurately ripped
    07 [95da091a] (04/23) Accurately ripped
    08 [378757f7] (04/23) Accurately ripped
    09 [cf2ac92e] (04/23) Accurately ripped
    10 [31427cec] (04/23) Accurately ripped
    
    Track [ CRC32 ] [W/O NULL] [ LOG ]
    -- [C67B45E5] [FE7B09E0] CRC32
    01 [EA289664] [FD25EC51]
    02 [5510B103] [BA8D8A92]
    03 [824866FF] [E5E4E8B1]
    04 [BB51AF5F] [B78BD2C6]
    05 [A64F03C2] [7D8C9937]
    06 [6EDFD398] [CE4DDB5B]
    07 [FEB2FA66] [4B709F32]
    08 [E12A46EE] [CC3FB96A]
    09 [6F24489A] [5930857B]
    10 [19CA3B60] [BE57D634]

We can be almost sure the other 19 results on this discID correspond to other pressings of this album (or maybe results on which HTOA handling screwed up ?), isn't it ?
Or could they be from a totally different album (there is another album with the same freedb id : http://www.freedb.org/freedb_search.php?wo...p;grouping=none )

I know it has no importance, the confidence here is 4 so my rip is for sure accurate but I'm curious rolleyes.gif

This post has been edited by Bregalad: Mar 2 2010, 00:30
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Porcus
post Mar 2 2010, 01:48
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QUOTE (Bregalad @ Mar 2 2010, 00:28) *
So an AccurateRip discID is almost surely linked to a single existing album (eventually in different pressings)
Right ?


With your reservation for singles, then the probability is really really close to zero, yes.



QUOTE (Bregalad @ Mar 2 2010, 00:28) *
So on this example (Protest the Hero - Fortress)

[...]

We can be almost sure the other 19 results on this discID correspond to other pressings of this album (or maybe results on which HTOA handling screwed up ?), isn't it ?

[...]

I know it has no importance, the confidence here is 4 so my rip is for sure accurate but I'm curious rolleyes.gif


A few such results do puzzle me as well. Have you tried to shift the offset in CUETools by + or - 5878, as in the link Greynol posts?


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