Discid collision

[fecund]

I often have my freedb submissions rejected with "Discid collision" errors. It's not the urf8 or "not found in DISCID" errors mentioned in previous threads.

Most recent one is with a disc with DISCID=9409750c.

dbPowerAmp says it's not in freedb. Now, there are two entries in freedb for that discid, neither of which is the right one- among other things, the track lengths are different.

Does dbPowerAmp retrieve the entries, see that the track lengths are wrong, and then say "no matches?" If so, I would very much like it to grey out the false matching categories in the FreeDB submission dialog. FreeDB won't accept an entry if it has the same category and discID as an entry, but it's not easy for the person submitting to predict if there's going to be a collision.

And I get a lot of collisions, about 1/5 of my submissions are rejected. FreeDb is filling up!

[xoas]

Re: Discid collision

You might want to refer to the FAQ at Freedb on this error message which states:

The disc ID, which is an important factor in identifying a CD, is not as good as it could be - in fact, it is pretty bad as a unique identifier for a CD. Therefore completely different CDs (with the same length in seconds and the same track number) can have the same disc ID. A disc ID, however, can only exist once in each of the 11 categories. This disc ID algorithm and the cddb protocol can unfortunately not be changed without loosing backwards compatibility to existing applications - and we definitely want to keep backwards-compatibility.
If you receive a rejection e-mail telling you, that there was a disc ID collision in the category you tried to submit the entry to, that means, that in that category the disc ID of your CD is already used for a different CD. In order to submit your CD to freedb successfully, you will therefore have to select a different category - even if it does not really fit for the music style of your CD. Since a specific genre can be specified for a database entry in addition to the category, a wrong category choice is not really that problematic.

Best wishes,
Bill Mikkelsen

[fecund]

Re: Discid collision

That's an informative FAQ (and one I've read) but it's a non-sequitor. I know about collisions, dbPoweramp knows about them, yet dbPowerAmp doesn't tell me what categories the collisions will happen in. Since it knows, it shouldn't let me pick those categories during submission.

[xoas]

Re: Discid collision

I'm not sure your assumption (that dMC knows in advance about collisions in Freedb) is correct. My understanding (which could be mistaken) is that freedb is independent of dBpowerAMP. Now dMC should know something about the cd and it would be nice if it had some sort of filter to help prevent (or better manage) collisions, I suppose (which I guess is your point). But I think this might require a program re-write to change the way dMC accesses the Freedb database. That would lie in Spoon's area (since he is the person who has written the dBpowerAMP programs). I have no idea whether such a change would be possible, but it does sound like it might be useful.

Alternately, it would be nice if Freedb could re-route your cd information automatically to a different category (or at least give you some open alternate category choices) if a collision occurs. But those measures would be up to Freedb to implement-not dBpowerAMP.

Best wishes,
Bill Mikkelsen

[fecund]

Re: Discid collision

If "Retrieve Titles" is checked, then dMC is looking up titles from freeDB already. Chances are it sees the records that have the same DISCID, and then discards them after it does some additional checks showing that it isn't the correct CD- asking the user, or comparing track lengths.

This should be a feature request- when dMC finds matching DISCIDs, keep track of them even if they're false positives. Then if the user opens the submit-to-freeDB window, grey out the categories for the false positives from the menu.

Access to freedb database doesn't have to change, the data during the initial retrieval has to be kept around a bit longer.

Re-routing to a different category would be bad, don't change user entered data! And if the user doesn't do a freedb lookup first and then tries to submit, well, then they deserve what they get!