how to extract tempo from an audio file?
 

Ok so I imported a song to pro-tools and I am going to record it track per track. I have a click and a drum track, in addition to the audio track with the audio file. I want the click to go to the beat/tempo of the recorded/imported audio track. Is there a way to extract the tempo from this track or determine what tempo it is in so that it makes sense with the rest of the session?

Re: how to extract tempo from an audio file?
 

"identify beat"

b.o.l.
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Re: how to extract tempo from an audio file?
 

yeah I just picked up on that...and well I select the whole audio track, dissable to conducter, and then click on identify tempo...but then what happens? how do I use whatever that thing did?

Re: how to extract tempo from an audio file?
 

The most effective way to use Identify beat is to pick an obvious transient of the kick drum (or any drum that is on the down beat of a bar), zoom in to sample level, and make an edit at a visually memorable point, preferably at a zero-crossing. Then, count 4 or 8 bars from there, find the same drum hit, zoom in, and make the exact same edit you did on the first hit.

95% of the time, the transient will look nearly identical at each edit point. I usually tab then option-tab back and forth between edits while at sample level to verify both edits are pretty close, if not identical.

Then, double click with the selector tool in the region. Identify Beat (Command-I), enter in what bar/beat each edit point is at, and you will now have accurate tempo for that 4 or 8 bar selection.

Now, if the track you imported was based off a programmed beat or sequence, that should be sufficient for the rest of the track. I check this by going somewhere near the end of the track, zoom in at the same drum hit, and make the same edit. select the region now created (which will be the bulk of the track) and do Identify beat again. Usually it will be off by a few ticks due to drift between systems. So if it says 98/1/004 I just make that 98 even and voila, you have a good and accurate average across the whole track.

THE ABOVE IS FAST AND WORKS WELL IF THE TRACK YOU IMPORTED WAS PROGRAMMED OR PLAYED TO A CLICK.

(Edit: To have your IB be true to the actual bar and beat number, make sure you count where your first edit is so you know what numbers to type in. I usually edit at Bar 9 Beat 1 and Bar 13 Beat 1 as my first IB to get an idea of the tempo, then move to the last 30 seconds of song, like bar 100 or something, and do my 2nd IB between Bar 13 beat 1 and Bar 100 Beat 1 )


If the track was played live,with no click (or even WITH), you will have to do step one, every 4 or 8 bars, depending on how tight the playing was. Just play it with the Digidesign click plugin up, and Metronome on, and if it goes off the click, do another IB from where you left off last to the bar before it went off the click. You may end up with slight (or even drastic) tempo changes. The fist chunk could be 120.23 BPM, the next 118.32 BPM and so on. The more IB's you make, the more accurate your tempo map will be. You will end up with many 4, 8, or 16 bar regions (I like to keep my IBs in the usual musical phrasing which is usually 4 8 12 or 16), each with its own tempo.

I also suggested editing on zero crossings, cuz say you decide to change up the arrangement, and move these 4 to 8 bar regions around, they will butt up against each other at zero crossings, so less chance of getting clicks at edit points.

That pretty much sums it up. Read the manual as well for a more detailed explanation of Idendify Beat and Tempo Mapping if you are new to it, which it seems you may be. Good luck!

MT

Re: how to extract tempo from an audio file?
 

Read my above post but before that READ THE MANUAL to understand the concept of Identify Beat (IB) and mapping out a tempo and how to make it work best for your particular scenario. Also, try the search engine here or on Google. Lots of info out there on IB and this topic as a whole.

MT

Re: how to extract tempo from an audio file?
 

Another way is to use beat detective. However, this will work best in little chunks (4-8 bars at a time) if it was not played to a click.

Re: how to extract tempo from an audio file?
 

If you wanted to do it manually, you could use this method.
..... Select a sample/region of the track and have it looping.
Deselect the Conductor icon and highlight tempo (box) by clicking on it.
Next tap the "T" button on your keyboard while it is playing.
Hitting the return button loads the tempo into Pro Tools.

Re: how to extract tempo from an audio file?
 

If the song has been created without any click track or other time related reference then I am afraid an every 4 bar analysis will not be sufficient.
Been there done that hundreds of times. The only real reliable tempo analysis/extraction from such songs is to do 1, 1/2 or even 1/4 bar analyzing by hand. This could easily take a full day but then you are safe.

If the song is a modern sequencer based recording then follow Mt.Everest first post but measure as much bars as you can as the average tempo result will be more precise.
The longer the sequence you measure the more precise the analysis will be, unless the producer made edits here and there.
You can let a bassdrum run through the track once you found out the tempo to check that there are no unexpected tempo changes due to edits.


Oliver

Re: how to extract tempo from an audio file?
 

Yeah, if the track is live, and wasn't played to a click (I find that with good players, recorded live to a click, you can get away with 4 bar chunks in general) I'd abandon IB all together and just use Beat detective with sub-beat analysis and be really aware of where BD puts the slice markers. Sometimes a few are WAY off and need to be manually adjusted.

You WILL end up with tons of tempo change events, in the decimal range, but if you plan on adding midi inst to the track (esp if its drums) you'll have to make it as precise as possible as to not incur any annoying flamming.

If the live stuff is ALL over the place, and you dont have the time required to tempo map every 1/4 bar, you could also try a sample replacement plugin or hardware box that you can trigger as a means of getting a midi note " reference map ", depending on what the music is like on your imported track. Ive has successful results with material that is transient heavy and not too Limited.

I just pick a sample that is triggered mostly by the loud drum hits or stabs in the music. You will also get triggers that are over the threshold but may or may not be useful.
Either way, I then use the resulting single note midi track as my " reference " track and copy the notes I want to the midi tracks that have my drum VIs and move then to the correct pitch, i.e. the sound i want triggered.

You can also use it as a visual reference if you want to play along with the track with gtr or something, and while using your ears mainly of course, you can also use the visual cues of where the midi triggered notes are placed.
For example, Ive done something where I had to OD a single chord stab on each down beat, and by watching the midi notes roll by, I could sorta be ready to play my chord in the right (technically WRONG :-) ) spot. Its not perfect, but could be a quicker workaround in a pinch.

Lots of options. So you gonna tell us what you ended up doing? haha

MT

Re: how to extract tempo from an audio file?
 

Just askin, but if u have a click track already on the session what difference does it make to find the tempo???

It seems like people nowadays get so married to tempo finding that they feel they can't go on without it???

U have the click so just go off of that it u need to fix, move, etc...