Variable tempo change?

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Re: Variable tempo change?

Permanent link to this post Posted by Gale Andrews » Fri Mar 10, 2017 3:16 pm

JayH1119 wrote: I have been able to effect the change I wanted using the time track, although I think my original suggestion for the interface would make it a LOT easier :D and quicker.

I'm glad you made your changes.

Is this what you mean:
JayH1119 wrote:What I 'm envisioning is a tool that will allow me to mark a number of corresponding points at various times in the tracks being synchronized and have a tempo and/or pitch change performed automatically between all those marks.

But we don't have that. Your speed faults were different in different places as I understand it, so to correct automatically, the speed faults must be autodetected. Capstan can do that. Have a look at the price at the bottom of the page. Also because of the intense number-crunching required, you must have a 64-bit computer to use it.

You can always make a "Feature Request". Do you really want automatic detection, or perhaps mouse pointer readout of the speed change/new timeline position of each Time Track envelope point? Or right-click over an envelope point and type in the speed change? Perhaps with an audio preview either side of that point?


Gale
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Re: Variable tempo change?

Permanent link to this post Posted by JayH1119 » Sat Mar 11, 2017 2:26 am

Image

It doesn't really match any existing audacity interface methods but this is what I was picturing: Being able to specify corresponding points between tracks and have one that has its tempo changed between selections so that the marks align in time.

Aren't 64-bit computers ubiquitous these days? I know I've been using one since 2011 or so.

Anyway, thanks again for all your time and help.
Jay
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Re: Variable tempo change?

Permanent link to this post Posted by Gale Andrews » Sat Mar 11, 2017 2:52 pm

JayH1119 wrote:Being able to specify corresponding points between tracks and have one that has its tempo changed between selections so that the marks align in time.

The key questions are:

- Are the tempo changes variable throughout the track?

- Do you want the changes to be automatic, so you don't have to mark the bad parts?

- Will you always have a reference track with unchanging tempo to guide you?

It's a reasonably common feature in DAW's to be able to drag a clip by its edges to speed change the clip (also affecting pitch). In the case you had with a reference track of correct length, this feature might have worked for you. So you can request this for addition to Audacity if you like. I think others would find it useful.

Thanks,

Gale
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Re: Variable tempo change?

Permanent link to this post Posted by JayH1119 » Tue Mar 14, 2017 5:51 pm

Gale Andrews wrote:- Are the tempo changes variable throughout the track?


Yes, Most likely this is due to a mastering technician making ad-hoc changes to adjust pitch by ear somewhere along the way. I can also see it due to old and/or substandard playback equipment during sampling.


- Do you want the changes to be automatic, so you don't have to mark the bad parts?


I don't see how that would be possible, so yes, the marks would always have to be made manually.


- Will you always have a reference track with unchanging tempo to guide you?


Yes, always.

It's a reasonably common feature in DAW's to be able to drag a clip by its edges to speed change the clip (also affecting pitch). In the case you had with a reference track of correct length, this feature might have worked for you. So you can request this for addition to Audacity if you like. I think others would find it useful.


It would seem that that functionality would be the same as effecting a tempo change, or a speed change, iow, the change would be linear and consistent throughout the selection. What I've been dealing with is inconsistent changes to the speed over time.
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Re: Variable tempo change?

Permanent link to this post Posted by Gale Andrews » Wed Mar 15, 2017 3:38 pm

JayH1119 wrote:
Gale Andrews wrote:Do you want the changes to be automatic, so you don't have to mark the bad parts?

I don't see how that would be possible, so yes, the marks would always have to be made manually.

Well, Capstan does it automatically.

JayH1119 wrote:
Gale Andrews wrote:It's a reasonably common feature in DAW's to be able to drag a clip by its edges to speed change the clip (also affecting pitch). In the case you had with a reference track of correct length, this feature might have worked for you. So you can request this for addition to Audacity if you like. I think others would find it useful.

It would seem that that functionality would be the same as effecting a tempo change, or a speed change, iow, the change would be linear and consistent throughout the selection. What I've been dealing with is inconsistent changes to the speed over time.

I'm not following how your idea of marking points on the track isn't a linear change, unless used in combination with a Time Track.

Would it help if Time Track control points could be dragged horizontally without changing their height, and if the points could soft-snap to an Audacity label (showing you when they are aligned with the label)?

We can always enter a request for an improvement to the Time Track interface, but I am still not very clear exactly what improvement you have in mind.

Thanks

Gale
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Re: Variable tempo change?

Permanent link to this post Posted by JayH1119 » Wed Mar 15, 2017 8:25 pm

In the illustration above, assume that the top track (sbd_0201) is the reference track and the bottom track (aud_0201) needs to have its timing match the reference - call that the track to be scaled.

Reference marks labelled '1' are at 10.96 and 11 seconds, reference marks labelled '2' are at 21.685 and 21.8 seconds and; reference marks labelled '3' are at 41.775 and 41.9 seconds. This shows that the track to be scaled is fast by 0.04, 0.115 and 0.125 seconds respectively.

I would want Audacity to:
1) Slow the track 2 tempo between 0 and 10.96 seconds by 0.37% (0.04 / 10.96). This pushes mark 2 to 21.725 seconds and mark 3 to 41.815 seconds.

2) Slow the track 2 tempo between 11 and 21.725 seconds by 0.7% (0.075 / (21.725-11)). This pushes mark 3 to 41.89 seconds.

3) Slow the track 2 tempo between 21.8 and 41.89 seconds by 0.05% (.01 / (41.89-21.8)).


Note that the example used makes for a very simple example, i.e. the reference track is consistently behind the track to be scaled. This may not always be the case though, e.g. imagine mark '2' on the track to be scaled at 22.5 seconds instead of 21.685.
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Re: Variable tempo change?

Permanent link to this post Posted by Gale Andrews » Thu Mar 16, 2017 4:21 pm

As described, those are linear changes within each section, are they not? So Change Speed could do it, and could do so most conveniently by setting the new length, but you would have to do it section by section in as many passes as it takes. This could change because we have a longer term aim to implement multiple selections in the waveform.

I still think any improvement in Time Track, which could do the task in one pass, would revolve around using Audacity labels instead of your lines in the waveform. Or perhaps right-click over a Time Track control point where you could enter the exact speed change or the new Timeline position.

Given Audacity has labels, it is not likely we will implement markers in the waveform.

Also moved topic to "Adding Features".


Gale

JayH1119 wrote:In the illustration above, assume that the top track (sbd_0201) is the reference track and the bottom track (aud_0201) needs to have its timing match the reference - call that the track to be scaled.

Reference marks labelled '1' are at 10.96 and 11 seconds, reference marks labelled '2' are at 21.685 and 21.8 seconds and; reference marks labelled '3' are at 41.775 and 41.9 seconds. This shows that the track to be scaled is fast by 0.04, 0.115 and 0.125 seconds respectively.

I would want Audacity to:
1) Slow the track 2 tempo between 0 and 10.96 seconds by 0.37% (0.04 / 10.96). This pushes mark 2 to 21.725 seconds and mark 3 to 41.815 seconds.

2) Slow the track 2 tempo between 11 and 21.725 seconds by 0.7% (0.075 / (21.725-11)). This pushes mark 3 to 41.89 seconds.

3) Slow the track 2 tempo between 21.8 and 41.89 seconds by 0.05% (.01 / (41.89-21.8)).


Note that the example used makes for a very simple example, i.e. the reference track is consistently behind the track to be scaled. This may not always be the case though, e.g. imagine mark '2' on the track to be scaled at 22.5 seconds instead of 21.685.
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