Tuesday, May 30, 2006

Poor Image Quality in IE or Surfing the Internet...

Anyone else doing tech support for the family? Probably all of us who work in this business.

I received a call just before the holiday yesterday (Memorial Day). My soon to be cousin-in-law was complaining that he had some sort of virus that took over his machine. He reloaded it several times with the restore disk but the first time he connected to the Internet the display on his laptop started distorting images. He was convinced it was a virus. He had called the manufacture several times and received several different reason why it was happening but none of the answers fixed his problem.

I sat down on the sofa with his laptop around noon at the family gathering for the Memorial Day holiday. Sure enough there was some distortion in the image quality. It looked pixelated in some fashion. It was very apparent in IE or IE related apps. The laptop used a widescreen display that ran 1200x800 natively. I had seen something like this before so I started research DPI related issues and it turned out there there were some pretty interesting posts out there. I learned some nasty stuff about Microsoft and Internet Explorer's ability to hand high resoution displays. Normally Windows likes to use 96 DPI but if you change it to something else like 120 DPI it has a nasty behavior. It will actually start adjusting image sizes. Here are some excellent references that I found when looking for information.

http://blogs.msdn.com/tonyschr/archive/2004/03/23/94391.aspx

http://msdn.microsoft.com/library/default.asp?url=/workshop/author/dhtml/overview/highdpi.asp

What it boiled down to was that Microsoft was scaling images sizes if you you used a DPI greater than 96. Using higher DPI settings is common with higher quality dispays. To disable image scaling you needed to add or adjust the following registry key.

HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\UseHR

A value of dword=0x00000001 will enable scaling.

A value of dword=0x00000000 will disable scaling.

It took me about 2 hours to find this solution and test it every which way I could to see if it would resolve the issue. When that did not work I reloaded the video drivers using the ones available from the laptop manufacture and from the video card maker. This did not work either.

I was running out of ideas. It was about time to go home when I started thinking that it may not be his laptop. The problem was definately related to Internet Explorer but I had ruled out the scaling issue. I decided to run a test. I knew where I had uploaded some images and I knew their original size. When I check the size of the file before and after downloading it I confirmed my suspicion. The file size had changed. The file had been compressed which reduced the quality of the image. It was happening every time. Holy Cow! Was it his ISP?

This guy was using Verizon Wireless Broadband Access. Its a VZAccess PCMCIA Card that acts as a cellular/digital wireless modem. It has its own software to manage the connection of course. I immediately suspected that Verizon was reducing the size of the images at the network gateway but before I accused them of it I started looking through the software interface. There is was Venturi Compression.

What is Venturi? I had never heard of it before. So lets let them explain. From their FAQ:

1 What is the Venturi client?

The Venturi client increases data throughput performance up to 5x when accessing the Internet over a wireless connection. This means that you’ll have fast online access wherever and whenever you travel.

The Venturi Client also improves the coverage of your data connection. In other words, your applications (web browsing, email, ftp, etc.) will perform well even when signal conditions are not optimal.


A simple removal of a default check box and it was turned off. One last clearing of the cache in IE and all images started looking crisp and clean. Everything loaded a heck of a lot slower but the images were back to their original quality.

If you want the whole explination of the options that are available you can see them at their site or read them below.

5. Can I change the image quality of my downloaded pages?

Venturi offers four performance settings that correspond to the rate at which wireless data is transmitted over the network. To change your performance settings, simply click one of the four levels in your pop-up menu and continue browsing the Internet as usual.

Here is a quick explanation of each of the four settings:

*Note: Faster transmission rates affect image quality *

Highest Speed: This level delivers the highest data access rates available by dramatically reducing the amount of data being transmitted.

Client Default: This level delivers data at high speeds while minimally sacrificing image quality. This is Venturi's typical default setting.

Good Image Quality: This level delivers good image quality with fast data transmission speeds.

Best Image: This level delivers the best image quality with above average data transmission speeds.

To view an image on a Web page in its original quality without using Venturi Optimization, simply bypass Venturi when reloading the Web page by applying the "Refresh Page" feature on Microsoft Internet Explorer or the "Reload Page" feature on Netscape Web browsers. Alternatively, reload the image by selecting Ctrl + F5 on your keyboard.

The option to reload images with original quality offers greater control of your online experience. For example, you can enable higher acceleration levels for general everyday use, then reload only a few images when viewing the original image is necessary.


Basically a whole bunch of caching and compression garbage. If you are in a hurry and dont care about quality then it is a useful application. If you don't know its there or do care about quality it is a pain in the a$$. Problem solved, rant complete.

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