I’m back

(August 11, 2009)

It’s been a while since I last wrote something here, but that’s because I was busy with Applied Mediocrity, my intro for Evoke and after that, I had some vacation. But now I’m back and have the time to work on my other projects, including this blog. So stay tuned for the next two real (technical) articles, which will be about some ideas I had about Linux Live CDs and an explanation of the effects in Applied Mediocrity.

NanoJPEG: a compact JPEG decoder

(April 29, 2009)

If you followed my works, you know that I like compact, single-file implementations of decoders for various media formats, and where such a thing doesn’t exist, I tend to write or at least port one myself. Now I’d like to add the third format to that list: Baseline JPEG images.
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Breakpoint 2009 Party Report

(April 16, 2009)

The is no such thing as easter. There’s only Breakpoint.
Happy Breakpoint!

This 1984-inspired text is from one of the bigscreen slides from this year’s issue of world’s largest Demoscene-only party: Breakpoint in Bingen am Rhein, Germany. As every year, the party takes place during what non-sceners call the easter weekend. And as every year, some friends and I were there, too.
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My new toy: Fujifilm F200EXR

(April 9, 2009)

I’m a happy user of the Fujifilm S9500 bridge camera since 2005, but lately, I noticed that it would also be really nice to have a second, smaller camera that I can take with me (almost) everywhere. This isn’t a problem in itself – there are countless compact point-and-shoot cameras at around 200 € on the market. However, most (if not all) of these suffer from too high resolutions and too small (1/2.5″) sensors. The days of the legendary F30/F31 with its large 6-megapixel sensor and unrivalled low noise are also long gone, so my »new camera« project was on hold for a long time. That was until february, when Fujifilm announced the release of its new compact F-series model, the F200EXR, based on the highly anticipated SuperCCD EXR sensor. After reading the first beta reviews and seeing the first example images, I immediately ordered the camera and it arrived just in time for my Paris visit, where I had the perfect opportunity to test the camera. Here’s what I found out.
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H.264 Decoder Benchmark, Part 2

(February 26, 2009)

After the H.264 decoder benchmark I did when DivX 7 came out, I got some comments that I misrepresented CoreAVC by using an outdated version. Recently, I repeated the benchmarks using the newest version of CoreAVC fresh from their website. I also used more computers to test the decoders on, and the results were very interesting.
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Four generations of iPod nanos compared

(February 16, 2009)

Over the last few years, I bought one specimen of all four generations of Apple’s iPod nano media player, mainly to make rePear compatible with each new model. (In fact, rePear’s main development target are iPod nanos.) Here are my thoughts about the benefits and drawbacks of each generation.
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KeyJ’s Blog 2.0 (or rather, 2.7)

(February 9, 2009)

For a very long time, this blog was run by WordPress 2.0.x – this was the current version when I started it, and I kept updating it for a while, but after I built the captcha, I stopped doing so. The reason is that I implemented my captcha as a direct hack in WordPress’ sources, not as a plugin, not even a my-hacks.php file. In the meantime, I some security holes appeared: I frequently found invisible spam injected into my posts. I have never found the actual hole through which they did this, but I disabled everything that could be problematic (all this Web2.0ey XMLRPC crap, for example). In particular, I excluded all hosts from a certain spam-friendly provider from my site. This helped a lot, until last week, when I suddenly found that my Windows 7 review has not only been altered, but replaced by invisible spam.

This was the point when I finally had enough – I upgraded the blog to WordPress 2.7 yesterday. To my great surprise, the test transition, performed on a local copy of the site, worked absolutely flawlessly. I could even re-use my theme without changes, which was my greatest source of fear. On the real server, there was still the little problem of the PHP memory limit which was too low for WP 2.7 (why on earth do they use more than 8 MiB, even without plugins and locales?!), but this has been fixed with a simple mail to my friendly webspace provider (thanks, Rafayel!).

Everything worked, except the captcha, which I reimplemented as a proper WordPress plugin today and activated just now. By the way, in the 22 hours without the captcha, I already got over a dozen spam posts. Sigh. Let’s see how long this installment of the site works :)

Compiler benchmark

(February 6, 2009)

I usually write my demos using Microsofts C Compiler for Win32 and GCC for Linux. But how good does Intel’s compiler optimize? And can the performance of MSVC and GCC be improved using a clever selection of compiler switches? That’s what I wanted to find out, and so I wrote my own little benchmark based on some code of my demos and let it run through all these compilers with different options. The results are a little bit different from what I expected …
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A quick look at Windows 7 Beta 1 … Not!

(January 15, 2009)

Sorry, but this post has been vandalized by spammers that somehow altered the post text. If anyone has a saved backup of this post, please give it to me.

DivX, the new king

(January 6, 2009)

Today, DivX Inc. released the new version of its famous video codec. Usually, this is utterly uninteresting news, but not this time: Version 7 is actually not an MPEG-4 ASP codec like its predecessors, but a H.264 one, based on the implementation of MainConcept. This makes the codec a lot more interesting, especially since the decoder part is free (as in beer).

The H.264 software decoder situation on Windows was a bit complicated: There just was no perfect decoder. The InterVideo and CyberLink come only with their respective Blu-ray player applications, the one in QuickTime is complete crap, the Nero one doesn’t want to work in applications other than Nero’s own. So we only had ffdshow, which is open source, cool, but a little bit slow, and CoreAVC, which is blazing fast, but you need to pay for it.
As of today, this problem has been resolved once and for all: DivX 7 is the ultimate H.264 software decoder on Windows, period. I ran a little benchmark today and the results are very impressive: DivX 7 is always faster than CoreAVC, usually about 10% for CABAC sequences. ffdshow, on the other hand, is always slowest and makes the least use of multi-core CPUs.


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