Screen Capture with ActionScript

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While working over numerous projects I often had the requirement for doing a screen capture in AS3.0. Unfortunately I found no "ready made" solutions in google search that suited my requirements. But I did come across some great resources which helped me to develop a component for screen capture, and thought I would share my experience (and code) with you.

With a hope that this will appeal and help someone else out there, I have posted it here:

The Solution :

Below is the Main mxml page developed using Adobe Flash Builder, SDK 4.1, Flash Player version 10.1.0. In this example I am doing a screen capture of the stage.
I have added a video and placed 3 buttons, Record, Stop and Play.
On clicking on the Record button, the recording of the page starts. Once you click on stop, it stops recording.
Then click on Play button to see the recorded version. You may have other things/animations on stage for recording too, I have just tried with an flv.
The recording play is basically bytesArray of an FLV created on run-time. You can save it to your server by passing this binary data to any back-end technology - ASP.Net or PHP, etc.

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
width="955" height="600"
frameRate="24" >

             import com.dd.screencapture.ScreenCapture;
             import com.dd.screencapture.SimpleFlvWriter;

             private var screenCapture:ScreenCapture;

             private function onInit():void
                  screenCapture = ScreenCapture.getInstance();
                  screenCapture.source = stage;
                  screenCapture.fps = 12;
                  screenCapture.size( 400, 300 );
                  screenCapture.x = 400;
                  screenCapture.y = 250;
                  stage.addChild( screenCapture );

             private function startRecord( event:MouseEvent ):void

             private function stopRecord( event:MouseEvent ):void

             private function playVideo( event:MouseEvent ):void
   <s:VideoDisplay width="400" height="300" source="assets/myVideo.flv" />

   <mx:HBox >
       <s:Button label="Record" click="startRecord( event );" />
       <s:Button label="Stop" click="stopRecord( event );" />
       <s:Button label="Play" click="playVideo( event );" />

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Place the ScreenCapture.swc in lib folder of the flex project. You may also use this swc for any ActionScript 3.0 projects. Kindly note that this requires Flash Player 10.1 to run properly.

Note: The below ScreenCapture.swc has been renamed to ScreenCapture.swc.txt for security reasons (so remember to remove the .txt extension when you save it). SWC is a Shockwave Flash component file. A SWC file is a zip-like file (packaged and expanded by means of the PKZIP archive format) generated by the Flash authoring tool.

Interestingly, you can save the screen capture as FLV format by using this piece of code below:
var saveFile:FileReference = new FileReference();
saveFile.save( screenCapture.data, "video.flv" );//screenCapture is the ScreenCapture instance created in the above code block.

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Resources used: http://www.zeropointnine.com/blog/simpleflvwriteras-as3-class-to-create-flvs/
The links shows how to save BitmapData to an FLV in binary format and then save to dish using Adobe AIR, using FileStream. I have taken the part of writing the binary data for FLV and playing that FLV as stream on run-time.

This has been published at http://deepanjandas.wordpress.com/2011/02/05/screen-capture-with-actionscript/
1 Comment

Expert Comment

by:nardine zermok
Thanks to share your code, it's amazing and very easy to implement it.
however how can we manage the memory? as long as it's recording
all the bytes goes into the RAM, so it will be very useful to make some chunks
and send it in realtime on a server or local file to free the memory usage

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