Add measure matching to SYNC function

[Kartik Gupta]

When i press the sync button to match the beats of two tracks , it simply does not match. They rather go out of beat. Its like the sync function is not able to find out which beats are to be matched together.
Ps: I have been using virtual dj before this, maybe i am expecting more from this software, but i think if we look deep into the code we can solve this bug.

[Owen Williams (ywwg)]

Can you describe your setup more? How many tracks are playing? Are they properly beat-gridded? What version are you using?

[Kartik Gupta (kartikgupta0909)]

Here is the file 1 which i tried mixing

[Kartik Gupta (kartikgupta0909)]

This is the second file. Mix the two files attach and you ll be able to reproduce the bug.
And what i suggest is that this is a really important feature which needs to be corrected , i have an idea for a gsoc project regarding this, which would actually facilitate the djs to use this software.And yeah i can that gsoc project myself as i am a computer science student myself and also have an expereience as a Dj and also i have done a course in digital signal processing.

[Owen Williams (ywwg)]

I don't really need the actual tracks, I can't really help unless I have more information about your setup. What version are you using? Have you run bpm detection on the tracks? How are you activating sync? If you send a screenshot of your setup while you're trying to use sync that would help.

[Kartik Gupta (kartikgupta0909)]

Owen, the version 1.11.0 , and yes i used bpm detection, and sync function
matched the bpm , however beats did not match in the sense that the beats
did not sound together as they should. I just press the sync button, and i
guess this is how it works , however if there is a different procedure you
can let me know and i can verify that for you. However still if you'll say
i can record a video and send it to you.
Kartik Gupta
​

[Kartik Gupta (kartikgupta0909)]

Owen, the version 1.11.0 , and yes i used bpm detection, and sync function matched the bpm , however beats did not match in the sense that the beats did not sound together as they should. I just press the sync button, and i guess this is how it works , however if there is a different procedure you can let me know and i can verify that for you. However still if you'll say i can record a video and send it to you.

[Owen Williams (ywwg)]

Sometimes the beat detection is slightly off -- it may be necessary to check the waveform and make sure that the beatgrid lines are in the correct places. You can use the "align beatgrid" function to fix beatgrid problems. Even after that, slight mismatches in beats are normal, and you may have to adjust the sync slightly. Version 1.12 includes a newer sync engine that may solve your problems.

[jus (jus)]

@Kartip
I understand that you expects Mixxx to act as following by the click of the SYNC button:
* Match tempo (BPM)
* Match beats
* Match phase ( aka match downbeats)

We do not have downbeat detection or a way to manually set the downbeat of a track, it is quite common that tracks sound off even if they are beat matched.

Sounds off
========
Track A = 1-2-3-4
Track B = 2-3-4-1

Sounds ok
========
Track A = 1-2-3-4
Track B = 1-2-3-4

You have to listen to both tracks, nudge the tracks so that the downbeats are nearly aligned and then press the SYNC button.

Mixxx will sync the tempo and the beats, but not the phase.
Would make a nice feature though.

[Owen Williams (ywwg)]

We do plan to have measure matching, but not yet. Marking wishlist.

[Kartik Gupta (kartikgupta0909)]

For updating this, When i did the beat detection manually, the sync function worked. But i think we should have better beat detection algorithms so that the dj doesnt have to manually fix the beats.

[Be (be.ing)]

Related: https://bugs.launchpad.net/mixxx/+bug/753301

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/7849