ScratchML Data Spec

ScratchML, like GML, is an XML-based format for storing information about the position of the record and crossfader during a scratch performance.

This is a “beta” release of the .SML file format, with sample data for 1 turntable and 1 crossfader. The format is designed to accomodate multiple turntables and crossfaders and a wide variety of data capture techniques, but we’ve only field-tested it against the basic 1 deck + 1 mixer scratch setup, which is what we were working with this weekend.

The two most important fields are:

• <turntable> — stores data about the playback position on the record as a consistently sampled stream of floats, with <samplerate> samples per second.
• <fader> — stores data for crossfader movements, ranging from 0 (full-left) to 1 (full-right). This data is stored only when the fader actually moves, and is stored as <p> (position) and <t> (time) tuplets.

Sample data produced by LM4K, mostly baby scratches and flares: XML / JSON

Spec + commentary:
ScratchML r6 beta spec:

The ScratchML.com database can also automatically convert from XML to JSON for use in javascript visualizations. Change the .xml file extension to .json, and optionally pass a JSONp ?callback= parameter, like this.

During Art Hack Day we converted SML to OSC and broadcast it over the wifi for realtime visualizations — more info to come about that.