Does an app exist for lining up beats on similar audio tracks *exactly*?

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brassplyer

brassplyer

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I have an unusual issue, probably not a common one.

There's a karaoke site where you can find both mono and stereo versions of songs people have performed. I want to take a mono version with someone's vocal and line it up with the stereo version of the track.

The problem is, while it's the same track, for some reason the mono and stereo versions after processing by the site aren't beat-identical. The mono version ends up being slightly shorter than the stereo version. On a 4 minute song, maybe a difference of a second or so but more than enough so that they won't line up exactly. Other people's stereo versions of the song can be matched up beat for beat so it's something to do with how the site processes mono vs stereo.

Is there such a thing as an app that will match up two tracks like this so they're identically in sync?

I tried time-stretching the one with Soundforge and can get close but not close enough. The beat-sync drifts over the course of the track. Slightly ahead in one place, drifting to slightly behind in another, resulting in phasiness. I suppose it could be a desirable effect if that's what you were after but that's not what I'm after. It seems it would have to be an app that senses the beat pulses and matches them up.
 
The reason for the differences in time are two different system clocks. 1 second in 4 minutes would be a 0.4% difference. TO put that in numbers, one clock is runnnng at 44,100 Hz, the other at 43,923Hz. Not sure anyone/thing could make that fine an adjustment.

You could chop up the 'short' file into small pieces (as small as you want, knowing that you've got to handle each one separately), then line up each one. If you use small enough segments the difference in timing at the end of each segment would be unnoticeable.
 
I think beat detective in Protools does this, but I've never used it myself, and that's not much if you don't have protools.
I've seen people use it to make the bass conform to the kick, or whatever.

If it helps at all, I'd be googling terms like conform to tempo, identify beat, identify hitpoint, etc.

I could certainly do this manually in protools with elastic audio, but again, that's not much use to you if you don't have it.

If it's such a small difference that you only notice after 30 seconds or so, do what MJB suggested.
 
mjbphotos said:
The reason for the differences in time are two different system clocks. 1 second in 4 minutes would be a 0.4% difference. TO put that in numbers, one clock is runnnng at 44,100 Hz, the other at 43,923Hz. Not sure anyone/thing could make that fine an adjustment.

You could chop up the 'short' file into small pieces (as small as you want, knowing that you've got to handle each one separately), then line up each one. If you use small enough segments the difference in timing at the end of each segment would be unnoticeable.
Click to expand...
It seems to be consistent with this karaoke site. If it's mono it's always shorter. Stereo renditions are always exactly the same length as the original track, to the point where I can line the performance up with the track and cancel out the track to isolate the vocal.

The chop into segments thought while possibly plausible would be way too tedious, particularly on something I'm just doing for grins. Ergo I was hoping for some bot method to do it.
 
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