Webcam Capture AS2 CS5

Question

Hey everyone! I'm attempting to use a webcam to capture images (which this does ok) and then overlay the images over eachother with a low opacity.
The images will be of a users face, each time a new user takes a picture the new face will be overlayed over the old one.
The first problem is, no matter how much I alter the alpha levels, it does not affect the opacity of the bitmap, I know this is probably simple but I'm fairly new to actionscripting!
Also the next step is figuring out how to get the image to stay there once the next one has been taken. I was wondering am I right in thinking of dynamically creating a new movieclip for each bitmap taken and changing the alpha of the movie clip. Would this work as a solution of both problems?
Many thanks for any help!
[CODE]import flash.display.BitmapData;
import com.adobe.images.JPGEncoder;
var snd:Sound = new camerasound();
var bandwidth:int = 0;
var quality:int = 100;
var cam:Camera = Camera.getCamera();
cam.setQuality(bandwidth, quality);
cam.setMode(320,240,30,false);
var video:Video = new Video();
video.attachCamera(cam);
video.x = 20;
video.y = 20;
video.alpha = 10;
addChild(video);
var bitmapData:BitmapData = new BitmapData(video.width,video.height);
var bitmap:Bitmap = new Bitmap(bitmapData);
bitmap.x = 360;
bitmap.y = 20;
addChild(bitmap);
capture_mc.buttonMode = true;
capture_mc.addEventListener(MouseEvent.CLICK,captureImage);
function captureImage(e:MouseEvent):void {
snd.play();
bitmapData.draw(video);
save_mc.buttonMode = true;
save_mc.addEventListener(MouseEvent.CLICK, onSaveJPG);
save_mc.alpha = 10;
save_mc.alpha = 10;
function onSaveJPG(e:Event):void{
var myEncoder:JPGEncoder = new JPGEncoder(100);
var byteArray:ByteArray = myEncoder.encode(bitmapData);
var header:URLRequestHeader = new URLRequestHeader("Content-type", "application/octet-stream");
var saveJPG:URLRequest = new URLRequest("save.php");
saveJPG.requestHeaders.push(header);
saveJPG.method = URLRequestMethod.POST;
saveJPG.data = byteArray;
var urlLoader:URLLoader = new URLLoader();
urlLoader.addEventListener(Event.COMPLETE, sendComplete);
urlLoader.load(saveJPG);
function sendComplete(event:Event):void{
warn.visible = true;
addChild(warn);
warn.addEventListener(MouseEvent.MOUSE_DOWN, warnDown);
warn.buttonMode = true;
function warnDown(e:MouseEvent):void{
navigateToURL(new URLRequest("images/"), "_blank");
warn.visible = false;
warn.visible = false;[/CODE]

Answer 1

enderwiggin wrote:
So it turns out that so many of these cameras update at such a slow rate (or are dead/static) that the system (which only captures most of these cameras once every 30 minutes) does end up downloading duplicates. That does surprise me since I would have expected thermal noise to change some pixels.
When I originally wrote this I had it saving the images to disk and then checking them, but it was almost impossible to delete the file successfully if the image was determined to be a duplicate. I don't understand this. I don't see how having a duplicate file can in any way influence a 'delete'.
>
Rather than save in a ByteArrayOutputStream why not just compare the bytes in the buffer just read with those on the disk. I'm up for trying anything at this point, but I'm having a hard time figuring out how to go about this.Since after every buffer read you know how many bytes have just been read, using a RandomAccess file you can read that number from the file and compare them. If they are different then you change to just writing the new byte directly using the RandomAccess file.
Ideally, what I need is to read the image into just an array of bytes that I can compare against the last image and then write to disk. Which, as you are finding out, does not scale. Reading the whole of a file into memory is rarely a good idea.
I'm turning around and passing the array of bytes to another method by way of out.toByteArray() to do the check. By the way I'm limiting the number of simultaneous captures to 10, which works well it seems for most of the program's operation. So put the requests for capture into a priority queue and then process the queue using a finite pool of tasks.
>
As a note, I've already tried bumping up the JVM's allocated memory with no luck.... although that would've been a pretty poor long term solution anyways.Yep. If I have to allocate more memory then my solution is poor.