Theo Verelst Local Diary Page 47

I've ditched the usual header for the moment, I think it doesn't help much anyhow.
This page is copyrighted by me, and may be read and transfered by any means only as a whole and including the references to me. I guess thats normal, the writer can chose that of course, maybe I´ll make some creative commons stuff one day, of course I have made Free and Open Source software and even hardware designs available!

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  Wed may 21 23:49, 2008

Another page with color pictures, mostly by myself, but some not.

I worked on some subjects and report about them, and of course my opinions I hold to be valuable enough to tak enotice of. It´s not snooping in someones´ personal diary, I these pages are consciously public, the diary (maybe more aptly journal) is just not pretending to be more than what it is: not a lecture series, or a set of papers, or pages with another pretence then my opinions. I started this idea before Blogging existed, and consider blogging fine but not for me..

I hope the use of some small version and partial pictures I found on various web resources can be considered fair documentary use, if someone has a problem with their materials being used here, please let me know ( )

A little bikeride

And I took pictures: they´re a bit summerish. These don´t need to raise the question of which cam was used: a mobile phone! For the rest of the page: take a guess which type of camera was being used for the pictures.


I could have been a bit idillic, but a least it looks nice.

A WWII reminder in a field.


I read somewhere Amsterdam has free boating rules to put your vessel anywhere as long as you don´t attach it to something wrong. This is the north of Amsterdam where clearly there is space. I don´t have anything much at the moment, but I can´t use a boat at all even at the moment, it´s been years ago since I sailed a day. I read about electric boats they seem to come of age lately, there are some decent motors with a few hundreds watts of power to power small boats or inflatable rubberboats with.

It would be nice to boat through here and make good film.

This peacock somehow got into a house neighbourhood, maybe it strayed from some farm, I doubt it is wild (though there are half wild chickens around somewhere, see a number of pages back)

The Schroedinger coder from the BBC

Dirac and schroedinger are names from the early 20th century physics scene but currently used by the Brittish Broadcast Corporation to refer to video codecs which do wavelet based compression. Out of interest I downloaded Dirac a little while ago and was able to do a little with it (see an image some pages ago) and now it was Schroedingers´ turn. In essence I compiled ffmpeg, and goy schroedinger compiled in so I now have an ffmpeg which allows dirac files to be encoded and decoded without being overly slow (dirac isn´t speed optimized, schroedinger is, but I think they´ll be joined again).

Wavelet coding is kind of cool and movie material should be better of with it than with fixed convolution interval based coders like most other things (including mpeg and h264) though that is anout perceived realism and quality of certain kinds, not necessarily some direct measure of coding efficiency. I tried out jpeg2000 quite while ago (see local diary pages) which is also wavelet based and which took quite some computer time, the schroedinger coder encodes about a frame per second on a normally fast machine, which isn´t bad. I mean a frame/s in 1080HD, let there be no misunderstanding about that...

Pro stuff Theo! Shuuuuure.

These are some frames from movie segments transcoded over schroedinger, and some also over h264 (which is the best order?) and keep in mind this coding tries better to get an idea of motion and details as they appear naturally, which means frames are not the most important reference, I´ll have ot put on some example footage to make the point which is most important, but then most people can´t play back high bandwidth HD material!

A piece from a conservatory performance in the BIM house in Amsterdam filmed with the HC3 without putting down the tripod.

This is a frame from a scene where there is a pan going on.

Taking from a (forward) driving car.

Is your camera up to top specs, Theo? A well mother, lets see, it is a 1080i Sony HC3 which I´m using, which sure is good at more than a few things, and has a 2.2 Mega pixel Clearvid (CMOS) sensor and records in 25 (twentyfive) megabits per second mpeg-2 TS. It has a diagonal pixel gred based on RGGB patterns. I don´t know for sure wether there are 2.2M pixels colors or 2.2M x RGGB.

I recently played a little in the big Media Market store with the SR11 i think it is called which has 5.5 megapixels (of course a HD video cam, not photos...) and supposedly has h264 based recording on harddisc with a little less bandwidth and If I Recall Correctly optical motion compensation, which should be another leap ahead. These machines are kind of neat, even compared to pro HD machines, which can easily appear flat and boring. At any rate it IS hard to film in HD, quite a bit harder than good video, which is already hard, but it very rewarding to work toward recording movie materials and much more fun.

Some work of mine

Well, I got this from here

to so:

Which is cool.

What are we digging for?

Well., nothing nasty, these hundreds of kilograms (16 normally strong garbage bags full to the point of nearly breaking) of earth are removed for

some pond!

That´s all.

Some thrown in place but nice furniture

AES conference in Amsterdam

Well indeed, and I was there as associate member, which makes one get a visitor pass to a number of lectures and exhibitions.

A lecture of a dutch aes governor (I think it is the name)

The entrance

Well done but expensive dual level VU meters at the AES exhibition

Well, I guess not expensive compared with normal studio VU or peak meter bridges, but I used to make these things myself in highschool from Radio Shack chips and cheap LEDs...

A submarine?! Nono, this is a sort of surround sound with many speakers (subs and midrange) and multichannel sound recordings and artworks from Delft Univeristy. I don´t have the MX400, but my surround based on 4 corners is heavenly compared to this except for some special effects. You need better transducers, guys!

I sat in this room a number of times to check out the Technical Commitees of the Audio Engineering Society, and of course said some things I found essential. Most people were pretty nice, though some were awfull. I was amoung to highest educated I´m sure, and in fact in shorts one day, andit was fun to talk a bit about some audio subjects with varying parties. This commitee idea won´t change the world normally, but why not talk, isn´t it..

I used to be the leader of quite a different TC: at highschool when I coordinated the audio and lighting activities for years. I guess at the time I didn´t realise how high profile that was for must kids.

The 70s at the conference?!

Google Earth on HD Linux

I use an about 8 Megabit per second internet connection and played around with a linux application called googleearth which does something similar as google maps on a big screen, in fact also on beamer to as it were remotely sightsee in the US:

Absolutely marvellous!

the program work quite nice, the surface of the earth is visiable in 3D even certain houses and tall buildings are 3D which looks great from a low ange as skyline, and various cities and areas (like Silicon Valley) have pictures taken along many roads every 50 meter or so which can be seen as emerging 360 degrees (european degrees) sphere which can be rotated by the mouse. Thats work very nice and gives a good impression especially when real high resolution images have been made as is the case for certain scenes. They can even on a HD+ screen (1920x1200 pixels) be zoomed in!

Sometimes a rig on top of the black car where the pictures have been taken with can be seen...

Of course part of the fun is the virtual camera motion and on a good quality graphics card (in this case a portable quadro) imagining it is film. In fact there is even a working flight simulator!

Even more electronics and mechatronics

Well a very good thing is I finally did a little effort to use the capacitor arrays I had made (see a number of pages ago) in the main amplifier which is used for everything like a HiFi system, TV sound, movie (HD DVD) sound, instrument amplification (like piano sound) and studio reference system, so that its electrolitic capacitors which was used to ground the main feedback voltage divider has been replaced by a non-polar, and high quality capacitor.

The red array can be seen with the duct tape on the bottom of the pcb they are on to isolate it.

And indeed it sounds even clearer and more transparent in certain ways. I´m not sure a casual listener would hear the difference, but I think it´s great. I´m sure it matters for big power transients, too.

For connaisseurs, this is a frequency counter which I burned in the Xilinx Spartan 3E starter kit board, couting the frequency of a PWM controller I made with the MPS430 TI microcontroller with USB programmer:

It is an example project from the Xilinx website, but I VHDL compiled it myself and created a PROM file wo that the project starts up from the board flash memory automatically. It appears to work good.

Maybe I´ll do some sodering

and use this little chip (the wires are half a millimeter apart...)

which is a magnetic sensor chip which can determine the rotation of a circular magnet put on top of it, lets say connected with this:

a conrad knob and axis and feedthrough assembly. That should be good for a remote volume control with very fine sensitivity (at least 256 or even more steps per 360 degrees) and very good speed (up to many full circles per second accurately, the chip can even be used in a motor feedback system).

Another electronics project waiting already for years is a self made high quality (really) microphone preamplifier based on a TI digital gain controlled analog signal path chip whcih I put on an adapter board. Above a XLR connector chassis part, and these are other essential parts (on top of a box):

A small 15 watts (still fairly heavy, and I don´t know what the coupling capacitance is) toriod transformer with clamping flanges, two 24 volt voltage stabalizer chips, and fast clamping diodes. Of course this is for the 48Volt Phantom supply.

These diodes should have the required peak current and reaction speed, I compared the datasheets of the diodes from the Texas Instruments Typical Application schematics diagram and these which I could actually get for little money:

pretty small, but they should be able to have little affect on the microphone signal and yet make sure the large 33 uF coupling capacitors (good quality conventional, not elco!) with the stabalized 48 Volt and metalfilm phantom resistors can never damage the sensitive chip input stage.

A mountain in Spain

After I graduated more than a few years ago I was in Spain on holiday as I recall the view was on this mountain in the north:

I used my first car, but did replace the (whole) engine with someone at the time, and replaced all kinds of essentials, including brakes, disks, distribution belt, starter engine, ettc. It worked great, about 150km/h over the french highways was fun with the little red Renault 5, it didn´t break down at all, but I constantly checked the oil and coolant levels, I guess it also worked better on the roads of the original country.
Very quiet up there, good vacation. Pity there´s no road pictures on the european googlemaps.

We dansen de samba

Means "We dance the samba" in english too, this sounds a bit wrong, in fact in dutch it also indicating something like we are dancing the samba.

Like "I´ve got very big Cauliflowers" ("´k heb hele grote bloemkole") from the localy totally famous dutch artist (who I share no personal life with) Andre van Duin, it is the title of a big dutch hits from the 70s, from when I was a kid. I though some of the shows were hilarious and I listened enough to be able to recite parts, which I suppose is good for one´s language and performance sense.

This is where he comes from, the last part I knew as a kid:

Other early influences of mine, you don´t need to think ´let him indulge himself a little bit´ because I assure you it´s quite worthwhile music:

I knew this song from the hitlist and probably TV pop shows in the 70s, I guess I was young to appreciate this kind of advanced music.

Another piece I music I remember singing along when I was pretty young:

Jean Michel Jarre