5%ish faster as3 JPEGEncoder

        public function encode(image:BitmapData):ByteArray
        {
            // Initialize bit writer
            byteout = new ByteArray();

            bytenew=0;
            bytepos=7;

            // Add JPEG headers
            byteout.writeShort(0xFFD8); // SOI
            writeAPP0();
            writeDQT();
            writeSOF0(image.width,image.height);
            writeDHT();
            writeSOS();

            // Encode 8x8 macroblocks
            var DCY:Number=0;
            var DCU:Number=0;
            var DCV:Number=0;
            bytenew=0;
            bytepos=7;

            var width:int = image.width;
            var height:int = image.height;

            var pixels:Vector.<uint> = image.getVector(image.rect);

            for (var ypos:int=0; ypos<height; ypos+=8)
            {
                for (var xpos:int=0; xpos<width; xpos+=8)
                {
                    var pos:int=0;
                    const I8:int = 8;
                    for (var y:int=0; y<I8; ++y) {
                        var pixelRowIndex:int = ((ypos + y) * width);
                        for (var x:int=0; x<I8; ++x) {

                            //var P:uint = image.getPixel32(xpos+x,ypos+y);
                            var P:uint = pixels[pixelRowIndex + xpos + x];
                            var R:int = (P>>16)&0xFF;
                            var G:int = (P>> 8)&0xFF;
                            var B:int = (P    )&0xFF;

                            YDU[int(pos)]=((( 0.29900)*R+( 0.58700)*G+( 0.11400)*B))-0x80;
                            UDU[int(pos)]=(((-0.16874)*R+(-0.33126)*G+( 0.50000)*B));
                            VDU[int(pos)]=((( 0.50000)*R+(-0.41869)*G+(-0.08131)*B));
                            ++pos;
                        }
                    }

                    DCY = processDU(YDU, fdtbl_Y, DCY, YDC_HT, YAC_HT);
                    DCU = processDU(UDU, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
                    DCV = processDU(VDU, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
                }
            }

            // Do the bit alignment of the EOI marker
            if ( bytepos >= 0 )
            {
                var fillbits:BitString = new BitString();
                fillbits.len = bytepos+1;
                fillbits.val = (1<<(bytepos+1))-1;
                writeBits(fillbits);
            }
            byteout.writeShort(0xFFD9); //EOI
            return byteout;
        }