Scaling, Encoding, Loss of Quality

[jai-interest-2]

i have used scaling operations in the past,, all of which have mostly excellent quality if you store the file using filestore operation. perfectly happy with these.

however, i am currently working on storing the images in a db for reason we wont get into.... and these images need to be moved to a byte array. servlet served images on scaled on the fly. (i know dangerous memory problems)

strange thing i cant seem to get to the bottom of. using the same scaling method i had previously used with the filestore operation that rendered excellent results is loosing a lot of quality.

sample code first of the scale with filestore that works well.. then of scaling to the byte array..

                        double hRatio = ((double) edgeLength) / ((double) image.getHeight());
                        double wRatio = ((double) edgeLength) / ((double) image.getWidth());
                        double scale = Math.min(hRatio, wRatio);
 
                        ParameterBlock scale_pb = new ParameterBlock();
                        scale_pb.addSource(image).add(scale).add(scale);
                       RenderedImage  image = JAI.create("SubsampleAverage", scale_pb, qualityHints)
                       JPEGEncodeParam param = new JPEGEncodeParam();  
                       param.setQuality(1.2F);  
                     
            ParameterBlock pb = new ParameterBlock();
            pb.add("/tmp/test.jpg"+ );
            pb.addSource(pum.writeRenderedImage());
            pb.add("jpeg");
            pb.add(param);
            RenderedOp op = JAI.create("filestore", pb);  
                          op.dispose();

-----------------
                       double hRatio = ((double) edgeLength) / ((double) image.getHeight());
                        double wRatio = ((double) edgeLength) / ((double) image.getWidth());
                        double scale = Math.min(hRatio, wRatio);
 
                        ParameterBlock scale_pb = new ParameterBlock();
                        scale_pb.addSource(image).add(scale).add(scale);
                        RenderedImage image = JAI.create("SubsampleAverage", scale_pb, qualityHints)

              ColorModel cm = image.getColorModel();
                int width = image.getWidth();
                int height = image.getHeight();
                WritableRaster raster = cm.createCompatibleWritableRaster(width, height);
                boolean isAlphaPremultiplied = cm.isAlphaPremultiplied();
                Hashtable properties = new Hashtable();
                String[] keys = image.getPropertyNames();
                if (keys!=null) {
                        for (int i = 0; i < keys.length; i++) {
                                properties.put(keys[i], image.getProperty(keys[i]));
                        }
                }
                BufferedImage result = new BufferedImage(cm, raster, isAlphaPremultiplied, properties);
                image.copyData(raster);
               
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                try {
                        ImageIO.write(result, format, baos);
                        } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                }
                byte[] bytesOut = baos.toByteArray();
--------------------
bytesOut looks like crap... images here -->

http://denniscg.com/20090506/filestored.jpg
http://denniscg.com/20090506/withoutfilestore.jpg

yes that is my beast... =)

the question is what is the "filestore" operation doing that i am missing when going straight to the bytearray that would cause this loss of quality?

any help from greater minds would be exponentially appreciated.
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[jai-interest-2]

one more thing... when moving to a buffered image i have also tried for jpegs... etc.. with no real luck.
                JPEGEncodeParam param = new JPEGEncodeParam();  
                param.setQuality(1.2F);  
                ParameterBlock pb = new ParameterBlock();
                pb.add(outputStream);
                pb.addSource(image);
                pb.add(type);
                pb.add(param);
                bufimage = JAI.create("encode", pb, hints).getAsBufferedImage();
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[jai-interest-2]

one thing,

param.setQuality(1.2F);

quality can only be 0 -> 1.0 (0-100%)

im not sure what effect that might have but might want to try it out.
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