Lossy Marvels

JPEG and MP3 are very popular formats for storing photographs and music respectively. They are both lossy formats and yet achieve amazing compression ratios without a loss of quality that is easily perceptible by normal people. I have always wondered how this is achieved.

The respective technical specifications are unfortunately too complicated to follow for a layman. Purportedly "explanatory" articles elsewhere gloss too much over the important points leaving me quite unsatisfied. I have fortunately come across two articles recently that seem to strike the perfect balance between these extremes.

"The Audiofile: Understanding MP3 Compression" was published in Ars Technica some time back and very nicely explains the compression algorithm behind MP3 as well as shedding some light over some of the apparent idiosyncrasies of this format. "Image Compression: Seeing What's Not There" was published by the American Mathematical Society and does a similar service for JPEG, including its successor JPEG 2000. (Come to think of it, these articles are "lossy" marvels in their own right.)

Now let us see if I can find an article with a similar depth that explains the MPEG video formats.

Alex

The Economist carried an obituary for Alex some time back. Alex was an African Grey parrot that Irene Pepperberg had trained to actually understand what it was talking about, unlike the parrots raised as pets which merely repeat whatever they hear.

For a parrot, Alex had impressive linguistic capabilities. It could describe objects, materials, shapes, colours, etc. It could express its desires. It could also ask questions. It could also count up to six and even had a notion of "zero". Very impressive.

ICFPC 2007: Epilogue

The results of ICFPC 2007 have finally been announced. Team Smartass from Google has come first (yet again), followed by United Coding Team from the University of Cape Town (South Africa) in the second place and Celestial Dire Badger (a lone hacker named Jed Davis) in the third place.

The organisers of the contest have an interesting report on the contest that also contains the "ideal" way one would go about solving the puzzles. Interestingly, Jochen Hoenicke managed to find a perfect DNA prefix some time after the contest was over. Impressively, Jed Davis came third by using a brute-force approach that won him the Judges' Prize - he was declared to be "an extremely cool hacker".

Update (2007-10-24): The organisers have now shared the video of their presentation about the contest at ICFP 2007.

Product Reviews by "Wayne Redhart"

Kingshuk pointed out the amusing reviews of products posted by a "Wayne Redhart" to the website of Amazon UK.

For some of the products reviewed by him, I found the product on offer more amusing than the review itself.