Quicktime frame editing

[Neowert]

So I am trying to tinker with ichat to put a watermark on every frame from the isight. I think I got pretty far for not knowing quicktime that well. So far I have a callback that is called each a frame comes from the isight. My callback is a bit messy, but you should get the idea. Since it is ichat, I cannot just draw to the ichat window, or the reciever would not see my watermark. I cannot seem to change anything. Here is the callback:

ComponentResult MySGGrabBottleProc (SGChannel c, short bufferNum, long refCon ){
//apeprintf("Called Bottle Proc\n");
ComponentResult err;
GWorldPtr filterBuf;
Rect filterRect;
Boolean done;
err = SGGrabFrame(c, bufferNum);
err = SGGrabFrameComplete(c, bufferNum, &done);
if(done){
PixMapHandle bufferPM;
Rect bufferRect;
err = SGGetBufferInfo (c, bufferNum, &bufferPM, &bufferRect, &filterBuf, nil);
bufferRect.bottom = 5;
bufferRect.right = 5;
SGSetCompressBuffer(c, 0, &bufferRect);
if (!err) {
//draw watermark
//SetPortPix(GetGWorldPixMap(filterBuf));

/* draw some text into the buffer */
//TextMode (srcXor);
//MoveTo (bufferRect.right - 20, bufferRect.bottom - 14);
//DrawString ("\pQT");
//TextMode(srcOr);
}
}
return err;
}


Just some info about ichat: It uses SGNewChannel to open a channel. SGDataProc is also called each frame. SGGrabBottleCompleProc (or something named like that) is not called. Neither are the series of DecompressSequence begin functions. Actually, DecompressSequenceBegin is called once.