Theo Verelst Local Diary Page 30

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Mon 23 22:07     2006

Time for another page? Who'll say, I just got my paper rejected for the Audio Engineering Society, but then again, I received a 5 (6 is the least needed to pass)  after 3 (!) trials for my university course Digital Signal Processing, and my synth is all digital processing, and works and sounds great.... Anyhow maybe not a good time to write, but then again, the machine I wrote about, and its software work fine, I at the time have become official electrical engineer anyhow, didn't need the crappy course ever (I at least was even officially electronician, too, which I consider more honorable), and I have another paper which is in review process, for probably the greatest (annual) computer graphics conference SIGGRAPH. Different subject, I made some things in two weeks or so, which was good to do, I'm still looking at what application to make exactly, but some hefty computations were possible.

My old car!

There are songs like 'my old piano' (D. Ross), people who like old fashioned cars, or want not the degeneration or de-quality-fication of things, but I liked my old car, think it is still fairly up to date and of superior quality in various ways and looks more decent and attractive in a modern way than anything else on the road, almost, maybe with the exception of extremes.

And what was the car I had from lets say 91 to 97 or so (I forgot) until It All Went Wrong, or in other words when I was unduely kicked out of my job environment without the promised ticked out of here or appropriate credits and ran out of money trying to figure out what terrorist holland was all trying to pull off. Well, an audi of course, the sort of kind which was well known to win ralleys, have 5 cylinders (probably one of the few, for instance for balancing reasons), that would drive comfortable and sportslike, and cleave to the road better than is good for a slip-course (which I did and where I  tried the car on the slipping track, and found its pretty hard to make it loose control, waaaaay out of the league of all the other people and their normal cars.

So this was sort of the car I drove for at least 160,000 km, a Audi 100 2.0 5 cyl injection / liquid gas, black, resembling this model (randomly taken from an add on the itnernet):

I when I first bought it (I think it was 6 years old) had to revise the engine, the cylinder head to be precise, which I had had bored, fitted with a number of new inlet and all new outlet valves, and fitted back myself with all proper precautions, and which lasted the same number of kilometers it had lasted in the first place again when the tax collectors repossesed it, at which point I compression was still fine and equal per cylinder.

I also replaced brakes, including disks, which made me feel pretty safe driving and braking unslow on the german autobahn for instance, and to begin with I had the selling garage change some rubbers which was needed according to the dutch automobile association (ANWB) purchase test I had done before I spent the appr. 5000 dollars for it at the time, which I had easily paid of in 2 years.

Quite expensive in tax, because of the liquid gas installation, but I drove not a little, so that paid itself back, and in such a way.... Great.

More Graphics

Like the above, but newer: a open scene graph graphics implementation of a 3 D audi!

For reasons of eastetics, though the environment is served by low CW-value (streamlined) natural gas, and high quality motor cars, this OSG demo application is a good recommendation for fast graphics demo, some fly bys give the impression a real forrest is flashing by:

Some other 3D models with fast graphics effects, such as glass, run on a fast machine, see below, taken form the OSG demo programs, which are maybe not dramatic, but good graphics.

All models can be translated and rotated in real time, which in this case makes the reflection change dymamically, which is cool. I have no artisitic inention with the choice of models, I picked some pretty or interesting ones withtout regard for the meaning.

This watch has the looking glass change mistyness when the viewing angle changes:

This externally found drumset looks great I think, maybe I'll use it as interface for and audio program!

The Moon, Mars, and Beyond

Some of the space (I think Hubble space telescope) images are stunning, like a sort of abstract artist has been at work

Not "pigs in space" but "God in Space" ?! This image and the following can be clicked to see a large version

I'm not sure about the colour sources for these images, sometimes spectral lines are filtered for various elements like hydrogen, oxigen, etc, which I found are very far from visible light, so that the colours then have nothing to do with what one would see normally.

Stunning pictures.

The Rejected AES paper

How much rejection is still acceptable? I don't know, I think its a good subject, and interesting, and I've written (published) relevant work before, that's not new, so basically I think it's wrong to not let an audience take notice of it and me some credit, I'd presume.

See the previous diary page for the (short) paper setup. Click here to get the pdf of the whole partial paper I sent in.

My own publisher: Fedora Core 4 / 64 on Athlon 64 and 768kilobit/sec upload ...

Send me money! Or relevant American job offers! Or fanmail! Gig offers with Mike Stern and Dennis Chamber, or maybe the YellowJackets! Or a ticket to the moon! Will this help?

The Shadow of Your Smile

Barbara (Streisand) sung it, various pianists in jazz and other people in country sung it, I found it in the realbook I had:

It's great to have good music around, and its always good to go on good (though on slow this would work, too) internet to get an idea of music from amazon samples, or of course from complete and well made MIDI files, like this one, which gives an impression of the song.

Excellent chords, like I was aiming for to learn more about, or rather confirm my knowledge and maybe learn the classical names of when I in 90 or so started doing a course in musical harmony. At the university music centre that was significant level, and I learned some names, and that I only intuitively knew the difference in melody and song lines and the possible (complicated) harmonistations for the various 7th chords, the in-major scale 7, the dimishied ("normal", dominant)  7, and the double diminished 7, applicable for instance in a dimished chord (c, e flat, g flat, a).

Of course the jazz combo at the time I played in was quite more into hipper and more recent harmonics in jazz/fusion, but still it never hurt to have a good course.

Who's that song title about now? I really can't  tell. Wish I could.

I've just made an mpeg sound file, about 3.5 megabyte size, 192kbits/sec (which this server can easily upload in realtime), made with Timidity, a Open Source Midi file player of decent quality, really quite a bit better then the normal windows midi players, so it sounds good enough to listen too, even though I use simpy the internet midi file.

In fact I tried a command combination to do the midi-to-mpeg rendering automatically, which is still quite a bit computation intensive on the 64 bit system, I guess it renders the file about 5x real time, but timidity isn't altogether pityfull about rendering samples, it takes its processing power to do that not too lame:

   timidity theshadowofyoursmile.mid -Ow -o - | lame -q 2 -b 192 - shadowofyoursmile.mpg
Try timidity yourself, using wav files or direct output to even a moderate sound card, it's worth  listening to the quality, like people with keyboards and midi files would probably appreciate.

High Definition TV

When working at university, or maybe already as a graduate student, in the EE scene the subject of High Definition Television was raised, and early implementations prototyped.

As it is, apart from DVD's the BBC is broadcasting a sort-of HD format on its satellite, which can be received over large parts of europe (holland and france at least). I thought that they had made their channels pay-tv, because an older, very cheap portable sat receiver didn't  decode most of them anymore, but now it appears that the format, especially for movies and fitting material is a 1024x576 pixel image, though that is with interlacing, which is nice.

As an example, here is an image from a news broadcast about the large fuel depot burning in england, in high(er) or medium high definition:

For a normal TV, it is not possible to see the advantage of this, even when a sat receiver allows the reception and decoding, simply because there are not enough picture elements on the tube. It is possible to use the ones there are inelligently, so the one channel looks better than the other, depending on the kind of signal enhancements and the type of TV.

For a picture like the above, a higher resolution screen is needed, and the material with more information in it, in this case the picture was shown on a computer screen (1600x1200 actual pixels in true colour) with a sat receiver capable of higher resolution, and the screen bandwidth and decoder speed to keep up with the required pixel update rate and decoding speed.

Intoxicating? Almost, pretty good, to get hooked on a bit when the encoder and channel work along, and the de-interlace and motion compensation c.q. filtering match and are ok for the material. Some DVDs, which can easily have such resolution and higher, don't have the naturalness of pictures because the image is optimized dead, or simply can't be played right on systems which are too slow.

Another example, I think I did no image processing at all, or intelligent (temporal) de-interlacing, which usually makes a still look unsharp:

Would the BBC also go bankrupt? Here's an example image from "The Omen":

And one from the also unprocessed sat received film The Tower of Evil:

It would be cool to pick up a camera and shoot some material wich can be broadcast and seen at such quality, and with my type of audio system connected, and good DA converters. No comparison with the sh* about 'broadscreen' and all kinds of image processing messed up regular tv qualities anymore, or the milkpackage 'surround' 'experience'...

As a comparison, the highest quality unmessed-with 'normal' broadcast quality PAL signal on a good TV is like what can be achieved with for instance the real-time mpeg-2 (6mbit/s) pinnacle box, which I currently regularly use with dune on linux (Fedore core 4, 64 bit with a Athlon 64), which can be 'improved' my a good player (like mplayer) and some filtering maybe, but that usually messes things up and gets boring after a while:

Not bad, but I prefer Higher D!

The sat receiver is in a fast, even 'hip' pc: A Pentium D (930) dual core at 3 GHz with a 955 chipset, dual banked memory and a NVidia 6700 graphics card and a dual channel TV and sat receiver built in. A view from the back of the server and sat-receiving PC as I currently can use:

At the left the PC is connected with a small 35 cm sat receiver dish, which allows 2 channels of simultaneous HD material (from the same satellite of course) to be viewed and / or recorded, so two at the same time, fo the above quality.

The Athlon 3.3 server machine allows at least 4 videos to be seen/played back simulateneously, and the dual core also allows viewing of at least a few HD channels, but it has a built in pixel-based image filtering chip which isn't making more than one media player (on the server I use multiple instances of mplayer which is easy) at same time very altogether happy, though it is certainly possible to put on a dvd and the sat and a big play back in winamp (video) and windows media player and stay under dangerous loads or get memory bandwidth problems. Even fairly heavy 3D graphics at the same time works.

I didn't know there were sat front ends which could feed to receivers from a single dish and LNB but this is even quite sensitive enough and really a tiny (camping!) dish.

Oh the wires are, lets see, everything from a number of battery chargers for cameras and such to usb for pinnacle, webcam, dsp devboard, synthesizer, etc, to ethernet (3 x 100 baseT) multiple audio connections (7.1 possible) and a mixer and such to the not visible self made audio amp and such and various (long) video connections.

Bezier subdivision in hardware

Well, that sounds like graphics work, and it is: my graduation work at university was about Bezier surfaces being used in a graphics design system.

I had read an articlewhich was (aprt of) the basis for my work about a chip for doing a certain rendering job very fast, and I've now made that chip sortof to begin with, a bit broader in setup though.

The prototype is shown here:

I'll make a page about the subject : where all the programming files for a 4 stage, 3D, 16 bits subdivision/selection/bounding box chain with >30MByte/Sec DSP bus connection and DSP communication and compuation test program are made available in Open Source and Free form, except for commercial purposes, than I want a piece of the revenues or so, I don't know.

I've done these kinds of things myself, looong ago too, which is good:

It's called breadboarding, to prototype electronics circuits, in this case from the  wikipedia page on TTL,Transistor Transistor Logic, which was the first famous and very widely used and important family of logic chips, used in most computers from the 70 till deep in the 80s and even in the 90s.

The reason to do less of this is that a suitable programmable logic chip can do the same and is flexible, and probably faster to program on a professional workstation, though honestly I do some things on a breadboard a lot faster than remaking the programmer files for a FPGA on a fast work station...


I saw this some time ago at the god channel and I think it is digusting, so only intended for research purposes, not for pleasure or the feeble minded.

It's from a dutch service, see here in windows media format, about 56 meg in total, it should be streamable real time from the server if you have moderate dsl, and it starts with a little while of green picture before normal image appears.

Makes one need to think about what vietnam was about, I recently saw Full Metal Jacket, and also I read about the nuclear rockets, and saw short film fragments about all kinds of nuclear experimental blasts after hiroshima, most a lot stronger than that bomb. There's a job to be done.

Stardust is coming to a lab near you?

The 7 year travel over a few million kilometers through space of medium sized spacecraft ended in a desert in the US, where from the capsule a sort of icebox has been taken from its extension boom, with in the kind of ice compartiments a transparent material will be put under a microscope with a imaging device making probably a million and a half (IIRC) or so images which will be peered at by tens of thousands of people through use of the internet in search of 1/100th millimeter small space particles, gathered during the very fast space flight all the way past pluto and back.

The quite low budget research facility has a webcam, this is from a week after the capsule had landed back, with only some damage to a battery during impact maybe:

Probably the first comet particles from space:

And most probably amoung the first interstellar dust particles ever seen by man:

Historic! Of course the composition of the particles can tell things about what's out there, and what possibly has been in the universe long ago.

The sun also is subject to recent and relevant research:

see the surface of the sun.

Nukes in space?

It appears to be possible to use nuclear rocket propulsion . In fact the latest Nasa Administrator (in the National Aeronautics and Space Administration gouvernment organisation that is the president), Griffin, Talked about it recently. The reason is a practical, not a theoretical one, one needs a lot of energy in space, which is hard to bring in another way: a big tank of gas is very heavy.

There are already nuclear devices in space, apart from actual nuclear rockets having been designed already in the 60's or so, which are very small special type of radioactivity based units, for instance powering the current New Horizons spacecraft which has recently taken off to Pluto with the heaviest rocket thus far made by man, with a speed of 40,000 km/h or so, to power its system for 10 years with a continuous 200 Watts of power.

Analog Synthesizers and Copyright

In principle, also by law in western countries, the maker of a analog sound synthesizer design has the intellectual proprty rights of the creation.

As electronic machines are serviced by service companies or engineers, schematics are needed, and usually available from the factory.

For somebody without commercial or official business, it would be possible to use those schematics to build things themselves, or even for business purposes one could derive or copy a machine.

In fact in the software industry the layout of the fron panel, the operation of the knobs, and the sounds of the electronics are used very clearly, even without direct reference to the original, which I find bad taste. In fact I wonder if it is possible to make a computer program, call it Noog instead of Moog, and make it sound like an existing synthesizer, and use it's knob and case layout and sample its sound.

The sounds could be recorded, I'm sure that's hard to protect, but sampling music even for seconds has been forbidden in fact. Making of sounds by setting all the knobs or virtual knobs rigth on a synthesizer can be protected by copyright, too.

Well, it appears there are service manuals with schematics on the internet, or one can order them with certain companies, so I had a look and found for instance the Minimoog schematics, which I find great fun!

I've made the heart of this filter a few times in electronics, but I didn't have the rest of the diagram, which left me unsure as to how the circuit was driven in the original synthesizer I tried to imitate. In fact I even made a Spice (Circuit simulator) analysis of simulated circuits, and converted the output to a sound file, with success.

This spice-like simulation I made already long before the synth simulation companies existed, see here.

The original of another absolutely classic synthesizer, which is imitated too, from 1978 (!):