

What Paris looks like with an echo - SanderMak
http://www.washingtonpost.com/blogs/innovations/wp/2014/07/23/what-paris-looks-like-with-an-echo/

======
pdkl95
[http://www.warmplace.ru/soft/pixivisor/](http://www.warmplace.ru/soft/pixivisor/)

If you like this, I suggest checking out PixiVisor. It's an experimental tool
by NightRadio (Alexander Zolotov), who also made the _amazing_ modular synth +
tracker "SunVox".

PixiVisor takes a short video loop (~animated-GIF or sequence of images),
modulates the frames (progressive-scan) into audio. A 2nd instance of the app
(usually on another device) demodulates the audio back into _similar_ video
frames automagically.

"Similar"? Well... after picking up the multi-path room echoes and the
"colorful" transfer functions of the DAC, amp, speaker, mic, ADC, etc, there
is substantial distortion. This is intentional, as you can vary the signal
considerably and the receiver app still reliably demodulates it back into
video.

This hit the "wait, isn't that impossible?!" stage for me in this demo video:

[https://www.youtube.com/watch?v=HkdLAWPsONQ](https://www.youtube.com/watch?v=HkdLAWPsONQ)

Using two mono channels of an audio mixer to mix video live is already insane.
Then the effect insert is turned up, and various types of reverb get added _to
the video frames_ in a way that perfectly matches what you hear.

Also, this video, of live room echoes and hand waves that clearly result in
changing reflections/blocking across many frequencies. Multi-path is also very
visible.

[https://www.youtube.com/watch?v=mF5C93cDocA](https://www.youtube.com/watch?v=mF5C93cDocA)

It's even multi-platform! (Windows, Linux, OSX, Android, iOS)

/* _sigh_ , now I'm going to be goofing off with SunVox instead of writing
RSpec */

~~~
fuzzix
> by NightRadio (Alexander Zolotov), who also made the amazing modular synth +
> tracker "SunVox".

Heh, first thing I thought when reading the article was SunVox. PixiVisor is
closer in effect to what the article describes, but I was reminded of the
"SunVox: Sampler eats JPEG images" video:

[https://www.youtube.com/watch?v=ColyxxBzeiE](https://www.youtube.com/watch?v=ColyxxBzeiE)

------
janaagaard
Side note: You actually need permission to use pictures of the Eiffel Tower if
it is illuminated. In other words "it is no longer legal to publish
contemporary photographs of the tower at night without permission in France
and some other countries."
[https://en.wikipedia.org/wiki/Eiffel_Tower#Image_copyright_c...](https://en.wikipedia.org/wiki/Eiffel_Tower#Image_copyright_claims)

~~~
robin_reala
This happens quite a bit. I took a nice photo of the Asahi building[0] in
Tokyo and tried to add it to Wikipedia, only to be told that the gold
embellishment on top was considered sculpture under Japanese law and therefore
subject to copyright and not permissible on Wikimedia.

[0]
[https://encrypted.google.com/search?tbm=isch&q=asahi%20build...](https://encrypted.google.com/search?tbm=isch&q=asahi%20building&tbs=imgo:1)

~~~
_delirium
In some countries even just regular buildings are considered copyrighted if
they have at all nontrivial decoration or design, and photos of them require
permission of the person/company that holds the design copyright on the
facade. The keyword to find each country's laws is "freedom of panorama", an
exception to copyright law that allows photographing public places, even if
the photograph includes something copyrighted. Some countries give a blanket
exception; others give an exception only for buildings (but not sculptures or
other artwork that appears in public, which can complicate photographing a
building if it also has sculptures); and those differ on whether it includes
only building exteriors or also photographs of the interiors of public
lobbies; still others have freedom of panorama but only for non-commercial
use; etc.

Due to having to sort it out repeatedly, I think Wikimedia has the most up-to-
date rundown of each country's laws on the subject:
[https://commons.wikimedia.org/wiki/Commons:Freedom_of_panora...](https://commons.wikimedia.org/wiki/Commons:Freedom_of_panorama)

------
graeham
The effects are pretty cool, but I can't help but wonder how much better it
would be if done with a bit of intention and knowledge of what these
algorithms are actually doing.

"We found that while the raw data makes no music, the waveforms share
patterns"

Its not that surprising, since music is frequency based while pictures are
spatially based. I expect you could get something that sounded like music from
a picture if you did some Fourier-transform filtering before with different
interval domains (different sizes of 'chunks' being converted to frequencies).

~~~
parksy
These days there are a number of audio synthesizers which do basically what
you said, such as the Beepmap plugin that comes stock with FL Studio.

Among the first to use the technique artistically, Aphex Twin famously drew
his own face in the spectrum of his track "Equation"
([https://www.youtube.com/watch?v=wSYAZnQmffg](https://www.youtube.com/watch?v=wSYAZnQmffg)
\- skip to 5:20 for the face).

Here's a few more, if you're interested:
[http://twistedsifter.com/2013/01/hidden-images-embedded-
into...](http://twistedsifter.com/2013/01/hidden-images-embedded-into-songs-
spectrographs/)

~~~
kumarharsh
the Equation song does sound really interesting!

------
kimburgess
On a similar note, the images to sounds thing has been used by musicians /
producers for a while. One of the more high profile users of this is Aphex
Twin.

[0]
[http://en.wikipedia.org/wiki/Windowlicker#Hidden_images](http://en.wikipedia.org/wiki/Windowlicker#Hidden_images)
[1] [http://www.boiledbeans.net/wp-
content/uploads/2011/03/1ac745...](http://www.boiledbeans.net/wp-
content/uploads/2011/03/1ac7454c7382aefbd50246fca08c0c6a.png)

~~~
rch
I was going to post exactly this. The effect in Windowlicker is definitely
memorable.

------
JonnieCache
For all the naysayers, not understanding DSP is the whole point. The naive
abuse of tools designed for other tasks is a powerful thing, its a totally
different way of working than deliberate application of reasoned technique.

------
Artemis2
For glitch art amateurs, I'd advise /r/glitch_art:
[https://www.reddit.com/r/glitch_art](https://www.reddit.com/r/glitch_art).

------
thisjepisje
I think it would've been more interesting to apply a fourier transformation to
the image, convert that to audio, and apply the wah-wah (which is essentially
just a low-pass filter) to that.

~~~
mbrock
Why would you need a Fourier transformation to apply a filter?

~~~
thisjepisje
Because then you'd actually be low-passing the frequencies present in the
image, instead of some random bits.

~~~
mbrock
Huh? If you can apply an FFT and apply a filter in the frequency domain,
what's preventing you from applying the convolution in the spatial domain?

------
ris
Oh jesus I can't believe this made the washington post. It's basically a bunch
of people not-really-understanding DSP. It's a highly known and highly
explored field.

~~~
skrebbel
Yep. It's basically fractal art all over again. "Press random buttons until
something looks vaguely interesting"

------
boomlinde
It's not Paris with an echo as much as it is the raw data of a specific
digital encoding of a picture of Paris fed through a digital filter suited for
linear streams of samples.

The effect is a direct result of the encoding more than anything.

------
thegeomaster
I suspect that better sounds could be made from images if the data was treated
as if it were in frequency domain instead of time domain, because then some
filtering could make more sense. This could open up some more possibilities,
such as even transforming color distribution data into musical notes (I wonder
if nice-looking color chords can be transformed into nice-sounding musical
chords).

This is very interesting, and I love both coding and music, so I guess I'll
get on making something like that :)

~~~
yread
I'm not sure I understand your comment, but I think that's what is already
happening. Consider this: WAV is a sequence of samples - BMP is sequence of
RGB values. So you can more or less treat it the same.

If you would try to read JPEG (i.e. frequency domain data) as WAV it would be
a mess. The "appropriate" format would then be something like MP3 but you
would run into issues - MP3 contains more metadata in the streams, JPEG
encodes 8x8px 2D images while MP3 encodes ~576 1D samples...

------
mxfh
Whats next? Somebody discovers what a _High-pass filter_ can do to audio or
even images?

[https://en.wikipedia.org/wiki/High-
pass_filter#Applications](https://en.wikipedia.org/wiki/High-
pass_filter#Applications)

