How to get current preview time with ExtendScript

[watanabed]

Hi.

How to get current preview time with ExtendScript.

I want to get the current time of the preview like the expression "time," not time of the Current Time Indicator.

Thank you.

[Tomas Sinkunas]

Not quite sure what you mean by preview time, but if you're looking work area, then look at three 2 properties:

http://docs.aenhancers.com/items/compitem/#compitem-workareaduration

http://docs.aenhancers.com/items/compitem/#compitem-workareastart

[Mathias Moehl · Accepted solution]

An expression is evaluated at every frame and each time the expression is evaluated, the variable time gives you this point in time. There is no such thing for scripts, since they are not evaluated at each frame, but only once, when you execute them.

If you want to execute a script while a preview is playing, there is no way to know which frame is playing while the script is running (and if it is a long running script I am not even sure if playback pauses or not).

[Mylenium]

Agree with Mathias. Your idea doesn't make much sense to begin with, given how this stuff works. If you want to execute scripts and be aware of specific timing, you have to give them something to latch on to like markers, keyframes or the layer in- and out-points.

Mylenium

[EyalCohen]

Since there isn't a proper way to get the time during playback, I found this interesting workaround:

function getPlaybackTime () {
    // 1. Get the active comp
    var comp = app.project.activeItem;

    // 2. Read all markers in the composition (if there are any)
    function getCompMarkers () {
      var output = [];
      var markProp = comp.markerProperty;
      for (var i = 1; i <= markProp.numKeys; i++) {
        var marker = markProp.keyValue(i);
        marker['time'] = markProp.keyTime(i);
        output.push(marker);
      }

      return output;
    };

    // 3. Store the markers in a variable
    var origCompMarkers = getCompMarkers();

    // 4. Add a new marker (same as pressing the * key)
    var id = app.findMenuCommandId('Add Marker');
    app.executeCommand(id);

    // 5. Find the new marker we added and get its time and index
    function getNewMarker (origCompMarkers) {
        var newCompMarkers = getCompMarkers();
        var oldTimes = [];
        var newTimes = [];
        var diffTime = null;
        var diffIndex = null;
        for (var i = 0; i < origCompMarkers.length; i++) {
            oldTimes.push(origCompMarkers[i]['time']);
        }
        for (var j = 0; j < newCompMarkers.length; j++) {
            newTimes.push(newCompMarkers[j]['time']);
        }
        for (var h = 0; h < newTimes.length; h++) {
            if (oldTimes.indexOf(newTimes[h]) < 0) {
                diffTime = newTimes[h];
                diffIndex = h + 1;
            }
        }
        return {time: diffTime, index: diffIndex};
    };

    // 6. Store the new marker in a variable
    var newMarker = getNewMarker(origCompMarkers);

    // 7. Remove the new marker
    comp.markerProperty.removeKey(newMarker.index);

    // 8. Return the time of the new marker
    return newMarker.time;    
}

// 9. Enjoy :)
var previewTime = getPlaybackTime();
alert(previewTime);

I don't know why exactly, but it doesn't work if you preview only audio without video (if someone can figure it out it'll be awesome)