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Showing posts from May, 2005

H.264 - The Thin End of a Big Wedge

H.264, also known as MPEG-4 Part 10, also known as Advanced Video Coding, is the New Hotness when it comes to video codecs. What's it offer? Lower bit rate (and file size) than anything else out there, while looking better. Or higher resolution, also looking better, at the same bit rate and file size. Scalability from third-generation cell phones to high-definition audio. For example, a typical 320x240 multiplexed MPEG plays back at roughly 1.1 to 1.8 megabits of data per second; a QuickTime movie using H.264 video and AAC audio can do just as well in one half to one third the space (meaning faster downloads) - or at 1.1 to 1.8 megabits per second, can deliver two to three times the resolution. Suddenly, a "high-definition" version of something takes only as long to download as one the size of a postage stamp used to. And that "something" could be a music video, a television show, a Hollywood movie, or other content - the kind that drove sales of

The Earth Moved!

After 3 years of living in a volcanic, seismically active area, I've finally managed to feel an earthquake! Around midnight, I was sitting in the remote control room with three Japanese observers. The telescope was cheerily doing telescope things, including some rather precise guiding indicated by a crosshair in a window on my screen. Several minutes past midnight, the remote control room shook, and the crosshair on my screen jumped all over, indicating that the telescope (27 miles away, and 2.5 miles higher than us) was doing the same. A call to another observatory on the summit confirmed that folks up there had felt it too. A friend I was chatting with reported that another friend of hers who lives near me had actually been woken up by it, and within an hour or so, a colleague had emailed me from London (he's on the road, as usual) to ask whether I'd felt it. According to the nice folks at the USGS, 'twas a 5.1 magnitude quake off the southeast side of

I'll see you on the poorly-lit side of the moon.

It's been an interesting night so far at the observatory. My observers are three postdocs from the University of Tokyo. They have no professor with them, and when I ask who is in charge, who is responsible, who wrote the proposal... they all point at one another. :) They are using a 4-megapixel visible light CCD camera which actually takes rather nice pictures, and they're running it through our wide-field grism spectrograph. Their first question was "how do we rotate the slit on the spectrograph?" The answer unfortunately involved rotating the entire instrument rack on the cassegrain focus... which means every time they change objects, we have to do that. Did I mention the instrument rack is rotated manually? With various ropes being unfastened before each change in rotation angle and refastened afterward? And we have to use a hydraulic lift platform to get up to it?  Yeah. Fun. Fortunately they have a short list of objects to observe! Anyway, at twi

Welcome to the future, folks.

We just had a nice chat with a couple friends. One of the friends is in London. The other is in Stafford, about 40 miles north of London. We, of course, are in Hawaii. We all had live audio and video of each other, courtesy of iChat AV 3 , the latest version of Apple's audio and video chat program (which also does AOL-compatible text chat perfectly well, of course), part of the new Mac OS X 10.4 "Tiger." And we could have actually had a fourth party in on the chat, too. Hosting a multi-way video chat like this requires a reasonably good broadband connection (DSL or cable modem), a fast Mac (at least an iMac G5 , prices start around $1299 new), and a FireWire video camera like Apple's slick, tiny $150 iSight . But any computer Apple currently sells - even the $500 Mac Mini - is powerful enough to participate in a group video chat, with as little as an ISDN connection. And of course they can all do one-to-one video chats, one-to-one audio chats, and group aud

Uncovered: The Terrorism-Chowder Connection

Ask yourself this question: "Are old men standing in knee-deep mud and digging for clams A) a possible terrorist threat, or B) a defense against terrorism?" I'm not sure which one is least plausible, but in the last four years, the Boston area has seen both.   Some of the most productive clam-digging mudflats in the area lie on the sides of Logan International Airport bounded by Boston Harbor, providing a livelihood for dozens of people. After two flights out of Logan were hijacked and flown into the World Trade Center on September 11, 2001 ( not , mind you, by clam-diggers), various measures were taken to improve security at the airport, including   banning   clam-diggers from the flats. Eventually, a 500-foot-wide perimeter was set up around the airport, then altered to contain a 250-foot "warning zone" and a 250-foot "arrest zone." Meanwhile, the clam-diggers were out of work. They petitioned their legislators, and after 14 months