Microsoft’s HD Photo not better than Jpeg 2000?
Posted by Sachin Garg on 23rd October 2006 | Permanent Link
Update: WMPhoto is now known as HD Photo, and might become Jpeg XR in future.
A report by Graphics and Media Lab at Moscow State University (MSU) concludes “WMP’s quality is quite average, and there are no signs of “revolution” in compression ratio” and that “some one-year old implementations of JPEG 2000 significantly outperform WMPhoto in objective and subjective comparison”.
But this is NOT the final word. Bill Crow, program manager for Windows Media Photo gives an interesting review of this comparison.
Microsoft introduced this new image format back in May 2006, and it was touted as a ‘Jpeg killer’. Both better image quality at better compression ratios, and faster performance were claimed. They didn’t talked too much about the newer Jpeg2000 standard but it was always mentioned by them in presentations and they ofcourse thought WMP is better.
The results put together by MSU researchers change the scene, making it clear that WMP isn’t better than JPEG2000 (atleast as far as quality is concerned).
In his review of this comparison, Bill Crow (program manager for Windows Media Photo) has raised some interesting and legitimate points.
Bill said:
I was a bit surprised with the range of quality differences among the different implementations of JPEG-2000. The design of basic Windows Media Photo compression algorithm doesn’t leave room for that big a range of differences among different implementations.
Admittedly, I too was surprised by this when I saw MSU’s first report comparing the Jpeg 2000 codecs in September 2005.
But what this means here is that Jpeg2000 being a flexible standard, leaves enough room for improvement and future Jpeg2000 implementations might be even better than this, but with WMP this is the best you will ever get.
His comment on all compression errors not being equal is also interesting. In the slide he presented at WinHEC, I can see what he says:
Windows Media Photo delivers a more random distribution of error from lossy compression, independent of the frequency of the image content. The end result is artifacts that are closer to random noise, and in many cases, this is significantly less damaging to an image, especially when it will be encoded/decoded multiple times.
This definitely makes sense, but the visual inspection results by MSU guys leave enough room for debate here too.
His last comment on the ‘validity’ of images used for comparison is again valid. I would myself want to see results on a more modern and more detailed set of images. Most popular images used in image compression research are very old and a upgrade will be very refreshing (I hope he publishes his test set soon).
However, although these images are old and have lesser resolution than that supported by modern cameras, they still have an acceptable level of both noise and detail. My opinion/prediction is that the newer test set won’t change the relative results too much. It might change the absolute ratings (ratio/quality/etc…) but I don’t expect the relative standings of Jpeg2000 and WMP to change much (I am ready to be proven wrong here).
But one question is still left unanswered among all this. While Microsoft has always claimed “low-complexity” and “performance” as advantages of WMP, I have not seen any hard results on how much better they are, compared to both JPEG and JPEG2000. Their presentations always mention that it is ‘faster’, but in forthcoming comparisons I expect to see some results telling ‘how much’.
With Jpeg2000 winning the ‘quality’ battle, performance is the only point left with WMP. It still remains to be seen how much better they are on that front (or if the choice of test set changes results).