How To Sync Traktor To Reaper

I finally got Traktor to sync with something else - Reaper - using MIDI Clock (running on Mac OS X, on the same machine). Here's how I did it..

Start Traktor.
Start Reaper.
Open Reaper Preferences, select Devices > MIDI Devices.
Double click "Traktor Virtual Input" and select "use this device" and "send midi clock to this device".
In Traktor, open the sync panel thing up the top by clicking the metronome.
Click "EXT" button - this tells traktor to listen for MIDI Clock.

Now get a track (with an accurate grid!) loaded into a traktor deck.
In Reaper, have something that has a beat set up (i.e. a loop from a recording, midi loop, place some audio in the timeline).

Press play in Reaper so your loop plays forever.
In Traktor, the sync panel should show a tempo similar to the tempo in Reaper. You'll notice that it wavers about a bit.
Press play on your gridded track and click Sync.

The Traktor deck should be roughly in sync with Reaper! (In fact, it is loose enough that it sounds a bit like a real DJ is nudging it.)

Questions:
- If we send the MIDI over a network or MIDI connection to a different machine, will this sync well enough to bother with?
- Can we sync two copies of Traktor (on different machines) this way?

If you have problems (or corrections), comment below so we can determine what I really did to make this work.

Supporting AppleScript in a Cocoa Document-Based App

It seemed like it should be easy, and it was, but finding out how was hard. So I am posting what I did here in the hope that the next person wanting to do it finds the info they need here.

What I wanted to do

I had a Cocoa document-based app. I.e. I had followed my nose with Cocoa, and ended up with an app that supported multiple documents. Documents are represented by in subclass of NSDocument called MyDocument.

I wanted to support viewing and changing properties of the document from AppleScript.

Note that I wanted to support 10.5+, so the techniques here may not be appropriate for older versions.

How I ended up getting it working

1. Specify things in the app's Info.plist:

   NSAppleSriptEnabled = YES
   OSAScriptingDefinition = MyApp.sdef



2. Made an sdef file, which includes all the framework supplied stuff, and that MyDocument extends the framework document, and has a property, refered to by the key numBananas:

   <?xml version="1.0" encoding="UTF-8"?>
   <!DOCTYPE dictionary SYSTEM "file://localhost/System/Library/DTDs/sdef.dtd">
   
   <!-- declare the namespace for using XInclude so we can include the standard suite -->
   <dictionary xmlns:xi="http://www.w3.org/2003/XInclude">
   
       <!-- use XInclude to include the standard suite -->
       <xi:include href="file:///System/Library/ScriptingDefinitions/CocoaStandard.sdef" xpointer="xpointer(/dictionary/suite)"/>
   
       <suite name="MyApp Suite" code="LfMS" description="MyApp application specific scripting facilities.">
   
           <class-extension extends="document" code="docu">
           <cocoa class="MyDocument"/>
               <property name="number of bananas" code="Bana" type="integer" access="rw" description="The number of bananas in this document" >
                   <cocoa key="numBananas"/>
               </property>
            </class-extension>
           
       </suite>
       
   </dictionary>



3. Implement KVC accessors for the property. These looked (sortof) like:

   -(NSNumber*)numBananas
   {
       return [NSNumber numberWithInt:bananas];
   }
   
   -(void)setNumBananas:(NSNumber*)value
   {
      bananas = [value intValue];
   }
   

This was all that it took, and now I can enumerate all the docs, set their number of channels etc etc.

Apologies to all my regular readers if this is slightly outside your sphere of interest!