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Archive for the ‘Computer stuff’ Category

Vista grr

Posted by Jeff on November 3, 2008

So I got my spiffy (and shiny) new Dell XPS M1130 laptop. (2.1Ghz Core 2 Duo, 4GB mem, 250gig HD, LED backlit 13″ monitor… and Vista.) Each time I started the machine, or resume from hibernation, my hard drive thrashes like crazy for about 20 minutes. You’d think with 4GB of memory, the hard drive would almost never need to be accessed except when loading programs. You’d be wrong. Welcome to SuperFetch. This is a program that runs in the background and pre-loads from disk into memory to allow for faster load times for frequently-used programs. Well, it keeps trying to preload my 8GB virtual machine file (that I use to run Linux concurrently with Vista). Hence the hard drive thrashing. I can sort of see the logic of using a pre-fetch device… on a desktop. A note to Microsoft: I use a laptop, and I like to be able to suspend and re-awaken my laptop in a hurry so that I do things like… I don’t know… move it? When all of that stuff is pre-loaded into memory, before the computer can sleep or suspend, it has to either unload it, or write it out to a temporary disk file. Double the hard disk use, double the memory use, half the convenience.

Thankfully, this demon was pretty easy to exorcise from Vista with the right incantations.

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Garmin GPS makes some “interesting” routing choices

Posted by Jeff on July 15, 2008

I’ve seen this too many times for it to be a fluke with one device or even model. The Garmin mobile gps devices make some insane decisions for routing from one place to another and I can’t decide whether it’s due to poor maps or a poor routing algorithm. Our family uses the StreetPilot c550 and HVA uses the nuvi series, and I’ve seen the same issue with both.

A good example is our most recent trip to Cleveland from Milan. A reasonable person (and Google) would take US23 south to either I80/90 or I475 to get to the turnpike. Our garmin directed us to get off US23 at Summerfield, take that to Sterns, to Lewis, to I-75, to I-280, and thence to the turnpike. For those not in the know, these are all two lane back roads and while possibly more direct, it would be MUCH slower than staying on the highway.
On our first trip to Cleveland, we had to pull into a residential street to get out the laptop and look up directions online, since our Garmin kept taking us around in circles AROUND our destination, without actually taking us TO our destination.

I’ve seen the same thing happen with the nuvi series, where crews have followed the gps onto rural, 2-lane roads that end up being more direct but much slower, or have gotten stuck in the loop-around route.

I’ve triple-checked the settings in several of the units and they are all clearly set to choose the fastest route with all obstacle avoidance turned off. The weird thing is that our StreetPilot has actually tried to route us a couple ways around Toledo on several different trips to Cleveland, with the same start and end points, and all settings the same.

I am curious if I would experience the same bugs with another manufacturer (TomTom, maybe), or if it is a deficiency in a shared routing algorithm.

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Ambient Quadraphonic to 5.1 AC3 Recording

Posted by Jeff on March 27, 2008

Here’s my new workflow:
1) Import both stereo tracks into Audacity
2) Create two new tracks (Center and LFE)
3) Raise and lower the tracks to the proper top-to-bottom order for AC3 (at least, the AC3 that is output by BeSweet and ac3enc) – FL, Center, FR, RL, RR, LFE
4) Go to Preferences -> Audio Files -> check “Use Custom Mix”
5) Export to wav file, use the default mapping
6) Open the wav in AC3Machine (part of BeSweet); disable all of the range, compression, and balancing controls; export to AC3.
(Note that AC3Machine is downloaded separately from BeSweet, but requires the command-line version of BS. Also, ac3enc is a “plugin” download for BS.)

One note in particular to the Zoom H2… the left/right assignment seems to be reversed in both the front and rear files.

Next, I’ll try to figure out the Dolby Digital CD thing, as well as making a simple dvd using the AC3 track.

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Ambient surround recording

Posted by Jeff on March 26, 2008

I’ve been playing with quad-track recordings of ambient sounds (provided by mstock, using the Zoom H2), trying to convert them from a pair of stereo recordings (2 files with 2 tracks in each) to Dolby Digital/AC3 5.1 surround. Instructions were found here and here. I first used Wavewizard to combine the two wav files into one 4-track WaveFormatEX file. Then I used Wavosaur to add two more channels (the center and sub). Wavosaur is also a VST host, which allows me to use the H2-Zoo plugin to visually remix and balance the channels. Finally, I used BeSweet (and AC3Machine) to transcode the resulting .wav file to a .ac3 one (which can then be added as the audio track for a dvd.) But after playing both the wav file and ac3 file through my receiver (via XBMC), I realized that the tracks were not corresponding to the correct speakers.

Then I switched to the most recent beta version of Audacity, which can actually be used for all of the above steps except for the transcode to AC3. I’ve figured out that the multitrack wav uses the following track order:
RF, LF, RR, LR, Center, LFE
This is *not*, however, the order that AC3 uses. So if I want the surround audio for the dvd to play correctly, I’ve got to figure out that track order… later.

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