Software help archive

A read-only archive of old serato.com help threads.

Serato Scratch and BPM Tags

Product
Scratch Live
Version
-
Hardware
Ortofon | Serato S-120
Computer
-
OS
Platform
-
flatfeetpete 8:17 PM - 14 July, 2004
Hi there,

I'm an open source nerd who's written a few BPM detection algorithms, and I've been asked by an SSL owner to try to make my app Scratch Live friendly.

From what I can gather (I'm not a SSL owner, I'm working from an mp3 I received), it looks like the ID3v2 TBPM tag is treated properly (no decimal places, whole numbers only), but there's also a TT22 tag, which is new to me. If I wanted to add the ability to write tags Scratch live, what tags should I write to?

Any help greatfully received.
Thanks!

Pete
nik39 8:28 PM - 14 July, 2004
ffp, fat props to you for porting your bpm tool for SSL. If the crate editor can also be ported for SSL that'd be wonderfull!! (the option auf automatically updating crates once the files in the folders change is great (auto updating crates)

For those who dont knwo about the apps from flatfeetpete, check
finalscratch.sourceforge.net

Very interesting apps and articles there (he was the guy who brought up the idea of the lockgroove wave. With its help it was possible to proof to us users that there is something wrong with the vinyls of SSL (pitchdrifting issue))
STRyk 9:16 PM - 14 July, 2004
Wow! Ho flatfeetpete!! Again thank's for your cool app for FinalScratch !! (Now i'm on SSL lol)
Can your programm can calculate BPM on MP3s (ID3v2.3) ?
Thank's again ! :)=
Nick 10:19 PM - 14 July, 2004
I believe that the TT22 tag is what some applications (such as pcdj) write their BPM into. It's basically the BPM multiplied by 100 (and therefore only has two decimal places of precision).
DJ C-Zer 10:22 PM - 14 July, 2004
I have provided FFP with a sample MP3 that SSL tags. It creates tags that are as follows:

RVAD
TT22
GEOB
GEOB
GEOB

- From what I can see, there is no Content that is redeable from these "Frame IDs". I'm still searching with a hex editor that FFP recommended. I know you can do it FFP! You're hardcore man! Thanks again for hearing my cries and I hope your app can be a multi-suite soon.

I'd like to know if there is a way that SSL can refresh the BPM values entered outside of SSL without having to recreate the crate again. Thanks.
Serato, Forum Moderator
Steve W 11:04 PM - 14 July, 2004
The easiest way to refresh all the tags is to delete the scratch live database file while Scratch LIVE is not running. The contents of crates are automatically re-imported and their tags scanned. If you don't want to lose files that aren't in any crate, you could put them in a temporary crate before you delete the database file. Note that there is a database file for each drive, in home/Music/ScratchLIVE on your boot disk and in /.ScratchLIVE for other drives.

We plan to add a button to force a refresh of all ID3 tags.
nik39 11:18 PM - 14 July, 2004
Steve, just to make sure that there is no misunderstanding, FFP's apps primary concern is not that of updating crates (which you post is referring to), its main task is to calculate BPMs. On top of that you can organize crates etc.
flatfeetpete 12:12 AM - 15 July, 2004
Quote:
I believe that the TT22 tag is what some applications (such as pcdj) write their BPM into. It's basically the BPM multiplied by 100 (and therefore only has two decimal places of precision).

I've seen the *100 in the TBPM, but I've never noticed a TT22, but I wasn't looking too close.

PCDJ seems to place ID3v2 tags at the start and the end of the file too. The stuff at the end looks to be the MLLT tag, not sure how they've got it accurate.

Anyway I was mainly curious which ID3/ID3v2 tags I should write too to let Serato Scratch see BPM's. I'll probably start with a converter between the various formats (I've got Sony/SF's ACID and Traktor working), and then add in the offline bpm processing code I've been working on.

If you are reading the TT22 tag, do you need leading zero? PCDJ doesn't like it if it's not there.

Thanks for the help, and the quick response.

Pete
Serato, Forum Moderator
Steve W 12:27 AM - 15 July, 2004
nik39, the procedure I outlined is the easiest way right now to get Scratch LIVE to rescan the ID3 tags of your music without losing the contents of your crates.
nik39 12:47 AM - 15 July, 2004
Steve, oh you mean after FFPs app works and the bpms are written... so we can update the crates w/o big hassle. Sorry got it wrong. Thanks for the info.
Nick 1:48 AM - 15 July, 2004
Quote:
Anyway I was mainly curious which ID3/ID3v2 tags I should write too to let Serato Scratch see BPM's.

SSL reads both TBPM and TT22, so either one would be ok.
DJ C-Zer 8:15 PM - 15 July, 2004
Quote:
Steve, just to make sure that there is no misunderstanding, FFP's apps primary concern is not that of updating crates (which you post is referring to), its main task is to calculate BPMs. On top of that you can organize crates etc.


nik39, Steve W was refereing to my question where I said "I'd like to know if there is a way that SSL can refresh the BPM values entered outside of SSL without having to recreate the crate again. Thanks.". I don't think he was referring to FFP's app. Thanks.
DJ C-Zer 8:18 PM - 15 July, 2004
Quote:

RVAD
TT22
GEOB
GEOB
GEOB
quote]

I was hoping the Serato developers can explain these tags to me. And what there significant meaning is. I found these tags both with a hex editor provided by FFP and a program called ID3-Tag-It, which does a superb job of reading extensive ID3v1 and IDEv2 tags. Thanks guys.
nik39 8:28 PM - 15 July, 2004
Quote:

nik39, Steve W was refereing to my question where I said "I'd like to know if there is a way that SSL can refresh the BPM values entered outside of SSL without having to recreate the crate again. Thanks.". I don't think he was referring to FFP's app. Thanks.


Arg, youre absolutely right! I was looking hard for your post but couldnt find it, cause I thought I posted you to try out deleting the crates and reimporting, and I couldnt find that answer either (in the end I thought that thread was deleted or moved to an internal section and I gave up). God give me some new eyes :)
nik39 5:32 PM - 23 July, 2004
Quote:
nik39, the procedure I outlined is the easiest way right now to get Scratch LIVE to rescan the ID3 tags of your music without losing the contents of your crates.


Will there be a different procedure in the future to accomplish this task? I am also asking because, sometimes I only want SSL to update id3 tags of only a few mp3s, and its a pain to delete the entire database, because it then has to rescan the whole mp3s. Will there be a selective refresh of id3s on certain files only?
Serato, Moderator
AJ 1:31 AM - 25 July, 2004
If you only have a few files you want to update, you can just load the files to a deck. They don't have to be there for any amount of time, just load them one ofter the other and the tags will be rescanned.