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Tempo Map Resolution

Author petearch

When importing a MIDI track with tempo changes, is there any way to get a better resolution of the tempo map in Synfire? If I import a tempo ramp from Cubase, Synfire places 'jumps' at every beat, and it doesn't even begin with the correct tempo value.

As an example, I have attached pictures showing a ramp over one bar from 80 bpm to 110 bpm in Cubase. After import, Synfire starts the tempo at 83.694 (this should be 80) and 'jumps' on every beat until it reaches 110 at the end.

I would like to know if it's possible to get a finer tempo resolution (i.e. not a 'jump' on every beat) and an accurate starting tempo on MIDI import.


Mon, 2015-11-02 - 12:08 Permalink

From the Parameter menu, select linear interpolation for the Tempo parameter. The perfect linear line is an abstraction. Internally, also Cubase also needs to use steps. Too many tempo changes may also disrupt playback.

For a correct start value, you might need to enter it by hand into the inspector/editor and make sure the first value is placed at exactly position zero. 


Mon, 2015-11-02 - 22:21 Permalink

I can't seem to make that work, the Interpolation option from the Parameter menu is always greyed out. How do you make it active?

The reason I'm trying to do this is because it's not easy in Synfire to draw a tempo map with accurate start and end values. I therefore thought it would be easier to draw the map in Cubase and then import, but it is not imported accurately. Is it possible to make it easier to use in Synfire?

What is the reason for Synfire not importing the correct start value?

Thu, 2015-11-05 - 11:15 Permalink

You are right, tempo doesn't allow linear interpolation. My fault. Interpolation wouldn't make sense anyway, because that would generate tempo change events in 1/32 steps, which is excessive. Tempo is not really something that could change continuously either. It must be incremented in steps and those are barely noticeable even at steps as low as 1/4. It just doesnt look smooth on screen, but that's it.

To enter exact values, select the value with the span tool and type a number into the parameter inspector.

I'll check if there is a bug with tempo map import. Basically tempo change events are taken and added to the parameter unchanged. If the first tempo value is odd, it is probably the second value and the first might be dropped. Or the DAW exports them that way.

Can you post the midi file as an attachment? I would only need the tempo map. Or send it to support at cognitone dot com.

Thu, 2015-11-05 - 19:20 Permalink

I can't attach it to here because it doesn't allow .mid files to be attached so I'll send it to Cognitone.  However, when I re-import it to Cubase, it comes out exactly the same as in Synfire (with the wrong starting value) so I guess it must be a problem with the export from Cubase.

Cubase also allows you to export just the tempo map.  This generates an xml file with the suffix .smt (Steinberg Master Track).  Importing this back into Cubase works correctly, with exactly the same tempo ramp as the original.

Is it possible to import the xml file into Synfire? There's something in the manual about importing xml, but it says import with 'Cogwheel' but I don't know what that means. I'll also send the xml to you for reference.

What I meant about entering exact values was when drawing a tempo line in Synfire, you can't tell exactly what your start and end values are until after you've drawn the line. Yes, you can change them afterwards but that only changes the tempo at that point because there are jumps between points rather than a ramp from the start. Is it possible to have a floating or fixed text box showing the tempo value that changes dynamically while holding the mouse button please?

Sun, 2015-11-08 - 16:49 Permalink

Thanks for the file (to attach here, be sure you use lower case file extension "mid"). As you said, the MIDI tempo export is a bug with Cubase.

The XML is probably specific to Cubase only. Or do other DAW also support it?

XML is just a generic file format that doesn't say anything about its contents. The XML Synfire imports is used for device descriptions and string tunings only.

Sun, 2015-11-08 - 18:29 Permalink

Ok thanks, I'll report the bug to Steinberg. Can you comment on my other question please?

Is it possible to have a floating or fixed text box showing the tempo value that changes dynamically while holding the mouse button please?

I meant to say this would be while drawing a tempo line. It would make it possible to see the start and end values before letting go of the mouse button.

Sun, 2015-11-08 - 19:22 Permalink

Displaying values and results during mouse drag will be part of a general overhaul of the editor and apply to all parameters, also for Tempo. This is on the list already.