In Monday's New & Noteworthy we published some commentary from MacCreator's Eolake Stobblehouse regarding Piranha Inc.'s new Piranha Net lossy digital image compression format.

Piranha Inc.'s president, Mr. Don Ashley, has submitted this response to Eolake's critique.

Dear Mr. Moore,

We have reviewed the above referenced article from Eolake Stobblehouse and would like to present the following information to assist your readers in drawing an accurate conclusion regarding Piranha Net technology.

We are presenting a step by step review of the points of contention and for the purpose of this test we will be using the "Owl" image, which was used as the basis of the Stobblehouse conclusions. It should be noted that all other images on the Piranha Net web page tested in this manner would have the same conclusive findings.

1. Go to our website at http://www.piranha.com/site/products/pr_net_doc.htm to download the Piranha Net plug in. Follow the instructions to download the plug in and proceed to the image demonstration page at http://www.piranha.com/site/products/pr_net_demo.htm

2. Download the JPEG Owl image utilizing the "save this image as" command. Of course, Mac and PC user commands may vary.

3. Once the image is saved open the image in PhotoShop. Go to the "Image" menu and select "Image Size". Change your image measurement from inches to pixels. You will find the image measurement for this image is 1536 X 1024 pixels with a total uncompressed size of 4,805,902 bytes. As a secondary test of this JPEG image open this same image in DeBabelizer. The measurement will be displayed automatically, 1536 X 1024 pixels, 17 million colors, with a file size of 222,765+0 bytes.

4. Follow the same procedure to evaluate the Piranha image. Here is what you will find.
a. In PhotoShop you will find that the Piranha image is 1536 X 1024 with an uncompressed file size of 4,805,902 bytes.
b. In DeBabelizer you will find that the Piranha image is 1536 X 1024, 17 million colors, with a file size of 36,558+0 bytes.

It is our conclusion that this represents a clear apples to apples comparison. Additionally, both images are indeed displayed in the html format at 600 X 400 (to check this in Macintosh use "Page Source" under the "View Menu"). Netscape and Internet Explorer for Windows have comparable features. These tests clearly demonstrate that the Piranha image has not been pre-shrunk.

The Piranha compression ratio is 131.7 : 1 while the JPEG compression ratio is 21: 1. Furthermore, Piranha technology has been shown to provide the compression ratios described (and greater) in fully-controlled laboratory settings in which all variables are kept constant using standard scientific methods. These tests are clearly available for any and all to see.

We appreciate your interest in our products and invite all Applelinks readers to compare for themselves.

Thank you for this opportunity to present the facts.

Regards,

Don Ashley
President
Piranha, Inc.

I also asked Eolake Stobblehouse to comment on Mr. Ashley's letter. He sent this reply to Mr. Ashley.

Dear Mr. Ashley,

Indeed I wrote Charles Moore yesterday [see below], correcting myself. You are right that the two images are the same size. HOWEVER, *when* they are seen in the correct size, not scaled down by the browser, it can be clearly seen that the quality of the two is not comparable at all.

The two images as they can be seen without the artificial down-scaling can be downloaded here:

http://www.piranha.com/site/products/images/hresjpeg/owl.jpg

http://www.piranha.com/site/products/images/hrespby/owl.pct

(One should get the browser plug-in first at: http://www.piranha.com/site/products/pr_net_dl.htm)

Perhaps there *is* a superior compression technology here. But we will not know before we see two images of *comparable* quality.

Sincerely, Eolake Stobblehouse

Eolake's previous note to me, which he mentioned above was:

There is an addition to the Piranha story: It suddenly occurred to me to check whether the Piranha-compressed image might *also* be scaled down by the browser. It turns out that it is. Now the question is, why would they want to show both images in a scaled-down version? The question is clear when you view the images in full resolution (Try saving both on the desktop and dragging them into separate browser windows. The Piranha image may open in Simple Text.): Seen that way, there is a *very* clear difference between the high-quality JPEG and the piranha-compressed image. I mean a big difference. So even though they are not, as I thought, of different resolution, they are of very different quality and cannot be compared as is. This test does not show how much of a technology Piranha actually does have, but it does show that the demonstration they give is pretty much useless.

After a bit of testing: The lowest setting I can get Photoshop to compress JPEGs in is Zero in "save for web" mode. With that setting I get an image that is about 60k. This is to be compared to the 220k of the high-quality JPEG piranha puts up as comparison image. It is clear that the Piranha compression does something else to the image, because the artifacts in the image are much different from the JPEG Photoshop makes. But not better. In fact I would give the edge to the 60k Photoshop image over the 36k Piranha image. But I would not use either, they both look horrible. In short, apparently you can compress images to smaller sizes than you can with Photoshop directly, but you cannot by any stretch of goodwill compare the quality to a high-quality JPEG six times larger in file size, or anywhere near it.

Eolake

Applelinks reader Mark Newhouse had also weighed in with these comments.

Hello Charles and Eolake:

Re: New and Noteworthy

<http://www.applelinks.com/articles/2000/05/20000522120312.shtml>

I was intrigued by the information about this "new" compression scheme, and downloaded the plug-in. In looking at the code for the page with the Piranha-compressed owl image on it, I noticed that it, too, was being shrunk by the browser (<embed src="hrespby/owl.pct" scale=.395 width=600 height=400>) so I pointed my browser to the image, and QuickTime (and the plug-in) handled the image fine. But the results were not what I would call high-quality. See for yourself (you'll need their plug-in): <http://www.piranha.com/site/products/images/hrespby/owl.pct>

Myriad compression artifacts, that get hidden when you resize the image to 600x400. So all images are being resized, but at least the jpgs and gifs still look acceptable when viewed at their actual resolution.

Best,

Mark Newhouse
Keeper of the iBook
http://homepage.mac.com/ibook_keeper/

I also asked Mr. Newhouse for further comment on Mr. Ashley's explanation. He replied:

Everything they said is true.

However, what they did not point out is that when you view the owl files (theirs and the jpg) side by side, at full resolution (not shrunk in the browser) the piranha compressed image is full of compression artifacts, and would be unusable in a printed document. The jpg still looks very nice, and would be of sufficient quality to print (I only bring up print because it relates to the image quality issue). I believe Eolake pointed out that reducing the size of the jpg to 600x400, and applying a reasonable jpg compression, yields a file that is similar in size to the Piranha Net compressed image. For web work (which seems to be the focus of the product), it is a wash -- except that users need to download a plug-in (that goes into their System folder - I'd hate to see what havoc it might wreak on a Windows machine) to view their compressed images. So the standard jpeg technology wins out.

At least that is what this AppleLinks reader found when he did the comparison himself...

Best,

Mark Newhouse
Keeper of the iBook
http://homepage.mac.com/ibook_keeper/
iBook, iMac, iBlog
http://homepage.mac.com/iblog/

So there you have it. My best advice is to follow the various test steps outlined above and draw your own conclusions.

Charles W. Moore

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October 06, 2008