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Forum: VirtualDJ 8.0 Technical Support

Topic: Issues with Loops and Variable BPM

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I've spotted a couple of problems which seem to be caused when using tracks with Variable BPM.

Note: Smart Loop was disabled during this session.

This video https://youtu.be/N7T_sU3KZpk first shows that when using the Set Loop button on a regular BPM track everything works as expected:

Hit Hot Cue 2 to place the track where I want the loop to start.
Press the Set Loop button, a loop of 16 beats is created.
Press Play, the track begins and loops as expected. Note the Loop In and Out point are accurate and remain fixed.

The 2nd half of the video shows the bug when using a Variable BPM track. I load a new track with a Variable BPM but has had all the anchors added to ensure the CBG is accurate. I run through the same procedure as with the regular BPM track.

Hit Hot Cue 2 to place the track where I want the loop to start.
Press the Set Loop button, a loop of 16 beats is created. Note, the loop is almost 17 beats in length not 16 so the Loop Out point is wrong.
Press Play, the track begins, however after the 4 beat, the start point of the loop visually shifts.
When the loop repeats, it does actually start for the correct Loop In point, but then visually shifts once more after the first bar.
With the end of the loop being incorrect, the loop doesn't work as expected.


The second video is https://youtu.be/TeZohTKJLPU and I believe it is related to the same Variable BPM problem. Firstly I work with the same regular BPM track as previously.

I create a Saved Loop via the POI Editor of 16 beats long.
I have Snap enabled to ensure the start of the loop is aligned with the CBG.
The loop is set to 16 beats, and the Loop Out point is when you would expect.
Testing the loop, everything works as expected.

Repeating the above procedure with a track with Variable BPM, but accurately aligned CBG.

I create a Saved Loop via the POI Editor of 16 beats long.
I have Snap enabled to ensure the start of the loop is aligned with the CBG.
The loop is set to 16 beats, and the Loop Out point is short of where I would expect.
Upon clicking Hot Cue 3, note the visual start of the loop is earlier than expected although the position of the track seems correct when Play is pressed.
With the Loop Out point being wrong, the loop doesn't work as expected.

Hopefully I have explained the 2 issues accurately and the fix isn't too difficult. Let me know if you need any further information.
 

geposted Mon 13 Apr 15 @ 5:20 am
AdionPRO InfinityCTOMember since 2006
As long as the bpm is constant during the part that is being looped it should work.
Are there bpm anchors between the time you start the loop and the time the loop is supposed to be finished?
 

geposted Mon 13 Apr 15 @ 7:02 am
"As long as the bpm is constant during the part that is being looped it should work.
Are there bpm anchors between the time you start the loop and the time the loop is supposed to be finished?"

So I tried a quick experiment using a part of the track that had no BPM anchors inside the loop and everything functioned as expected and worked correctly. Therefore if there is a BPM anchor inside the loop it causes the problems.

Ideally taking in to account the BMP changes during a loop would be good as often with even small loops the tempo can vary enough to make a noticeable difference when mixing with another track.

Is this something you think can be improved?
 

geposted Mon 13 Apr 15 @ 9:03 am
AdionPRO InfinityCTOMember since 2006
The loop changing while it's playing was a bug of course, that will be fixed so it consistently uses the bpm at the start of the loop.

Taking into account the change of bpm during the loop is a little more difficult, so I can't say at the moment at which point that will be improved.
 

geposted Mon 13 Apr 15 @ 9:39 am
Thanks for the feedback...

I thought of a work around that I could use pending an update but there seems to be a small bug, see video https://youtu.be/NN6sQtn7Vw4

As you can see I am defining the Saved Loop in seconds rather than beats which appears to work a treat, however after I close and re-open VDJ, you can see that the Saved Loop has now changed from seconds to 8 beats. Obviously the loop is broken at this point.

A secondary minor issue was that whilst defining the POI and switching from Beats to Seconds, the green marked area didn't update until the wave form was scrolled meaning that you are left trying to grab the end of the loop marker but it's not actually where it is drawn (0:26) in the video.
 

geposted Mon 13 Apr 15 @ 11:16 am
Adion wrote :
Taking into account the change of bpm during the loop is a little more difficult


Just implement track warping instead (so the BPM can be straightened) :-)

 

geposted Mon 13 Apr 15 @ 11:45 am
AdionPRO InfinityCTOMember since 2006
Looks like there was indeed a bug with storing loops in seconds to the database.
Will be fixed next build :)
 

geposted Tue 14 Apr 15 @ 3:19 am
Great service, thanks!
 

geposted Tue 14 Apr 15 @ 4:25 am
When "smartloop : yes" + "loopBackMode : no" >> action "loop" normaly set a "loop in" with the size of the loop indicated for the deck with unique BPM track.
With a variable BPM track when there is a change during the loop, the "loop out" point is not set correctly.
Any idea ?
 

geposted Wed 17 Jun 15 @ 9:49 pm
Is there a way to indicate in the browser that tracks contain "variable BPM"(a new column or an added mark on BPM info) ?
 

geposted Wed 17 Jun 15 @ 10:03 pm
Is there a way to "lock" variable BPM files so when "batch - BPM analysis" is activated, information datas for these files will not be affected ?
It's sometime long to prepare a manual BPM analysis and easy to be loosed in a few seconds with the BPM analysis function...
Thanks
 

geposted Wed 17 Jun 15 @ 10:12 pm
You have made a good point. At the very least, there should be a warning message displayed if you try to re-analyse a track that has variable BPM edits made to it.
 

geposted Thu 18 Jun 15 @ 11:57 am
PachNPRO InfinityMember since 2009
I wouldn't display a messagen. Imagine 1000 edited files, and 1000 warning messages if you batch - reanalyze?
Not very good.

I'd suggest just do skip the values holding infos for the VBR.
 

geposted Fri 19 Jun 15 @ 3:41 am
I agree with Patchn and Grooveindj, just skip variable BPM tracks when batch is launched and show only one synthesis message indicating that there where variable BPM tracks skipped would be perfect ;)
 

geposted Fri 19 Jun 15 @ 5:59 pm
davidzfr wrote :
I agree with Patchn and Grooveindj, just skip variable BPM tracks when batch is launched and show only one synthesis message indicating that there where variable BPM tracks skipped would be perfect ;)


UP: Any info from virtualDJ developers ?
 

geposted Tue 14 Jul 15 @ 2:06 am
davidzfr wrote :
Is there a way to indicate in the browser that tracks contain "variable BPM"(a new column or an added mark on BPM info) ?


+1 I will vote for that. : -)

You should request the feature in the "wishes" forum area.

In VDJ 7 there used to be a * next to tracks with a prominent beat, so it's possible to add a small sign.

 

geposted Tue 14 Jul 15 @ 3:04 am
 

geposted Wed 22 Jul 15 @ 2:40 am
I kind feel like my thread got high jacked :-)

I've pretty much worked around the problem using seconds to define the loop, but it would be worth fixing this 1 day...
 

geposted Wed 22 Jul 15 @ 3:27 am


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