ltc4j

SMPTE LTC signal generator for Java

Disclaimer: At this moment, doesn't work properly

This library focuses on generating ltc signals. This implies that you have to handle the timing, but also this makes slowing and accerlating time possible.

Related libraries / programs

• artnet4j - working with ArtNet on Java
• ShowManager - send ArtNet, LTC and MTC (planned) timecode, dispatch OSC commands, scheduled music player
• JavaTimecode - timecode library, in Java, work in progress

Usage

Framerates:

• Framerate.FRAMERATE_24
• Framerate.FRAMERATE_25
• Framerate.FRAMERATE_DROPFRAME
• Framerate.FRAMERATE_30

An example of the LTCGenerator class

int hour, min, sec, frame = ... // times
Mixer mixer = ... // your output
int sampleRate = 44100; //audio sample rate
LTCGenerator generator = new LTCGenerator(mixer, Framerate.FRAMERATE_25, sampleRate);
generator.init(); // handle the exception
// by calling start method, the generator will begin playing timecode
generator.start();
// the currenty set time will be played.
generator.setTime(hour, min, sec, frame);

Using the LTCPacket class If you want to handle the the outputting on your own, you might want to use this class.

int hour, min, sec, frame = ...
LTCPacket packet = new LTCPacket(hour, min, sec, frame, Framerate.FRAMERATE_25);
byte[] data = packet.asByteArray();
// work with data

An example of timing With this example you can get a precise timing, that calculates time values from elapsed time, therefore not relying on perfectly on-time loops.

long start = 0;
long time = 0;
int framerate = ... // your framerate
LTCGenerator generator = ... // the generator instance
while (System.currentTimeMillis() >= time + (1000 / framerate) {
    long elapsed = time - start;
    long var = elapsed;
    int hour = (int) (var / 60 / 60 / 1000);
    var = var - (hour * 60 * 60 * 1000);
    int min = (int) (var / 60 / 1000);
    var = value - (min * 60 * 1000);
    int sec = (int) (var / 1000);
    var = value - (sec * 1000);
    int frame = (int) (var / (1000 / framerate));
    // work with time values
    generator.setTime(hour, min, sec, frame);
}