Getting Down and Dirty with XMP and AS3

// callback handler inside a NetStream subclass dispatches a custom event that  
// forwards the xmp data found in the callback handler
public function onXMPData( info:Object ):void
{
	dispatchEvent( new XMPEvent( XMPEvent.XMP_STRING, info.data, true ) ); 
}

// pseudo code
var video:NetStream = new NetStream( connection );
video.addEventListener( XMPEvent.XMP_STRING, xmpHandler, false, 0, true );
video.play( "h264_captions.f4v" );

private function xmpHandler( e:XMPEvent ):void
{
	// XMPMeta is root data structure for xmp data. Pass in the xmp data
	// we received from the NetStream callback
	var xmp:XMPMeta = new XMPMeta( e.xmp );
 
	 var xml:XML = xmp.serializeToXML();
	 trace( xml.toXMLString() );
}

private function xmpHandler( e:XMPEvent ):void
{
    var xmp:XMPMeta = new XMPMeta( e.xmp );
    // define a namespace that will allow us to "dot down" into the data
    // the XMP lib provides constants for many of the common XMP schemas
    var xmpDM:Namespace = XMPConst.xmpDM; 
 
    // "Tracks" is a Bag array containing XMPStruct types.
    // Let's take a look at how we can parse out the values in
    // first XMPStruct. NOTE: All XMP arrays start at 1 rather than 0.
    var track1:XMPStruct = xmp.xmpDM::Tracks[1];
    trace( track1.xmpDM::trackName );
    trace( track1.xmpDM::frameRate );
 
    // the second struct contains the array of speech-to-text
    // markers that we're interested in.
    var track2:XMPStruct = xmp.xmpDM::Tracks[2];
    var markers:XMPArray = track2.xmpDM::markers;
    var item:XMPStruct;
 
    for ( var i:int = 1; i < markers.length + 1; i++ )
    {
        item = markers[i]; //  a reference to the current marker of type XMPStruct
 
        // now we can simply look at all of the property values for each 
        // item in the array
        trace( "startTime: " + item.xmpDM::startTime );
        trace( "duration: " + item.xmpDM::duration );
        trace( "name: " + item.xmpDM::name );
        trace( "speaker: " + item.xmpDM::speaker );
        trace( "probability: " + item.xmpDM::probability + "\n");
    }
}

private function createXMPMarkers():void
{
    // create an xmp object and create a namespace for the Adobe DynamicMedia schema
    var xmp:XMPMeta = new XMPMeta();
    var xmpDM:Namespace = XMPConst.xmpDM;
 
    // create some markers and set some properties
    var item1:XMPStruct = new XMPStruct();
    item1.xmpDM::name = "XMP Standard Schemas";
    item1.xmpDM::startTime = 0;
    item1.xmpDM::duration = 15000;
    item1.xmpDM::type = "Chapter";
 
    var item2:XMPStruct = new XMPStruct();
    item2.xmpDM::name = "Dublin Core schema";
    item2.xmpDM::startTime = 0;
    item2.xmpDM::duration = 9999;
    item2.xmpDM::type = "Index";
 
    var item3:XMPStruct = new XMPStruct();
    item3.xmpDM::name = "XMP Dynamic Media schema";
    item3.xmpDM::startTime = 10000;
    item3.xmpDM::duration = 5000;
    item3.xmpDM::type = "Index";
 
    var item4:XMPStruct = new XMPStruct();
    item4.xmpDM::name = "Specialized Schema";
    item4.xmpDM::startTime = 15001;
    item4.xmpDM::duration = 50000;
    item4.xmpDM::type = "Chapter";
 
    // create an sequenced array to hold all of the markers
    var markers:XMPArray = XMPArray.newSeq();
    markers.append( item1 );
    markers.append( item2 );
    markers.append( item3 );
    markers.append( item4 );
 
    //Create Tracks Struct
    var tracks:XMPStruct = new XMPStruct();
    tracks.xmpDM::trackName = "TOC Markers";
    tracks.xmpDM::markers = markers;
 
    // Add the "Tracks" property to the xmp object and set its value equal to the track variable.
    xmp.xmpDM::Tracks[1] = tracks;
 
    var xml:XML = xmp.serializeToXML();
    trace( xml.toXMLString() );
}