Category: Scripting
Command Line Audio Editing With Sox
For my ritual spoken word software piece, I recruited a bunch of my friends to say the text of the ritual. Each “stanza” of the ritual has a call and a response, so I broke each recording up into individual clips for each call and response. That gave me about 28 files per person, and over 100 clips total.
The different participants all recorded on different hardware, and at different volume levels. I also wasn’t super-precise about trimming the clips, so each file had silence at the beginning.
This left me with two problems: some participants were much softer than others, and some of the clips lagged each other, which made for bad chorus effects.
To trim the clips, I used sox, a Linux tool for manipulating sounds, with the command:
for file in *.wav; do sox $file $file.wav silence 1 0.1 2%
This results in a file named foo.wav.wav for each foo.wav file in the directory, so I cleaned up with:
rename -f “s/.wav././g” *
Note that this scribbles over the originals, so keep backups. I’m glad I did, because 2% turned out to be a little aggressive, and trimmed off the beginning of clips starting with an “ma-” sound, such as “make us a…”. This is likely because the sound faded in slowly, and so got counted as part of the noise rather than the beginning of a sound.
There is useful documentation for the sox silence filter here.
Turning the volume up on the files was done with:
for file in *.wav; do sox $file $file.wav gain -l 8; done
and another pass of rename, as above. Adjust the “8” up or down to suit your needs. Positive numbers make it louder, negative make it quieter.
If you want to preview a sox effect, just replace “sox” in the command with “play”, and leave off the output file. For example,
play myfile.wav gain -l 8
will play myfile.wav with increased gain, but won’t change the file.
We Make Ritual Noise
For a festival that I attend, I’m writing a soundscape in boodler to provide the vocal component for a ritual. Here, I’m going to annotate what I need to do to run Boodler on my laptop, which I’ll have at the festival.
The main thing is that Boodler seems to default to OSS, and I use PulseAudio, so to invoke the ritual, you need to run:
boodler -o pulse –external disturbingrelics com.gizmosmith.disturbingrelics/Example
The -o option tells it to use PulseAudio, –external makes it load from a directory instead of a .boop package for testing purposes, and the rest is the agent to run.
To organize all the sound clips I’m using, I have a boodler package for each person’s reading of the ritual script. The script is in a call and response format, with 14 calls and responses, so each package has 28 audio clips, one each for the call and response. I named all the clips “call_N_…” and “response_N_…” (for N in 1..14) so that the program can figure out the call/response pairs by name.
Each package starts out as a directory with the 28 files and a metadata file in them. For the directory “sage”, I create the package with:
boodle-mgr –import create sage
and then install it with:
boodle-mgr install ./com.gizmosmith.sage.1.0.boop
Converting .MPG to .AVI with Linux programs
I am trying to convert .mpg files from a sony camera into other, smaller versions for distribution. The files are in the mpeg2video codec, with a resolution of 720×480 at 29.97 fps. Normally, I’d use ffmpeg for this, but apparently “This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.” Thanks Ubuntu, I’m sure that won’t screw up a few thousand people’s video conversion scripts.
Anyway, let’s see what man avconv has to say. I want no sound, and I want to start 55 seconds into the film, to cut off most of a boring first minute. Seeking into the video is -ss 00:00:55. The option -an drops the audio. So, avconv -i blue_ball.mpg -an -ss 00:00:55 blue_ball.avi should do it. And, in fact, it does.
Drinking with Robots
I am building a drink-dispensing robot. It has 5 pumps internally, so I want to find the set of five liquids that will produce the largest variety of mixed drinks. To do this, I’m going to need a huge set of drink recipes. I got a bunch from a cocktail database that esquire maintains, but the biggest list I’m aware of is The Webtender. Unfortunately, that database isn’t in a form that permits me to make queries to find out what is the maximal set of drinks that I can make, given the constraint of 5 liquid ingredients. So instead of the web interface, I want the raw data.
This means I want to download every single drink recipe from The Webtender. The URLs there are of the form http://www.webtender.com/db/drink/6217, so the obvious thing to do would be to write up a little bash oneliner that just wgets each of the files in turn. It would probably look something like this:
for (( i=1; i <= 6217; i++ )); do wget http://www.webtender.com/db/drink/$i; done
But it may be that The Webtender issues a 403 Forbidden error if you use wget, probably to prevent just this sort of hijinks. Unfortunately for them, wget can be configured to claim to be something else. These instructions provide the config file to cause wget to claim to be Mozilla on Windows NT, which The Webtender should have no problem with.
For my next trick, I'll use BeautifulSoup to turn the HTML files from the webtender and Esquire into a SQL database, and probably perform some form of normalization on the data, such as making all the measurements be in the same units.
Academic Problems in New Media Art
I’m trying to convert Deluze & Guattari’s A Thousand Plateaus into a corpus for use by a program. Among other things, the program will break the text down into its component sentences. The text has a lot of notes, which connect the text to a lot of other sources, but are not always written in complete sentences, and so will result in odd output from the program when considered as sentences.
So I’m faced with a choice: lose the notes, and so lose the cultural context and references to stuff that went before, or keep them and suffer degraded output. Nobody warns you about the odd stuff you’ll have to decide when you start doing new media “art”.
Coloring cells based on cell value in OpenOffice
OpenOffice (probably LibreOffice too) has limited functionality for setting the background color of a cell. I wrote a little macro that colors each cell blue, with saturation depending on the range of the value. This is in OOBasic, but it demonstrates the general idea, and the proper way of setting cell background colors.
Sub Main
End Sub
sub ColorCells
dim ii
dim jj
dim r
dim g
dim b
dim doc as object
dim sheet as object
dim cell as object
doc = ThisComponent
sheet = doc.Sheets.getByName("Sheet1")
for ii = 0 to 5
for jj = 0 to 626
cell = sheet.getCellByPosition(ii, jj)
r = 255 - (cell.Value * 255)65536
g = 255 - (cell.Value * 255)65536
b = 255
cell.CellBackColor = RGB(r,g,b)
next jj
next ii
end sub
Counting Instances of Things
This is something I seem to do a lot. Most recently, I was trying to see how many nodes of each degree there were in a graph, but it could also be used for word counts and such.
#Run through a list and count occurrences of each item,
#store them in a dictionary of items to counts
def bin(list):
bins = {}
for item in list:
if item in bins.keys():
bins[item] += 1
else:
bins[item] = 1
return bins
The key thing here is not really the little bit of python glue code to do the counting. What is key is to learn to recognize things that you do more than once, and automate them. A folkloric axiom of computer programming is that you need to do something either exactly once, or an unknown number of times. If you have to do it once, then the program should do it once. If it’s the other case, then the program should determine how often to do it, and then do it.
For example, if the program trims the whitespace off the end of a text file, it should either do it once (which allows the user to call it in a shell script loop if they want to process any number of files), or do it to any number of files. The alternative, having it process some arbitrary number of files and then fail, has two problems. First, it adds complexity. The program now has to keep a counter, check it, and fail when it hits a certain value. Second, the program, which previously worked in an infinite number of cases (that is, it would process N files for all N such that N is a positive integer), now has an infinite number of failure cases (fail for all integers greater than M), and has gone from complete success to complete failure, via the most difficult route.
Chatbot is done
I finished writing the chatbot that I was working on. It consists of a set of scripts to prepare the data, and another script that listens for incoming messages and responds. You can get the code and an overview of how it works here.
Obviously, I’m not publishing my chat logs. Use your own. It is designed to work with Pidgin’s HTML-like format for chat logs, but it could be modified to work on almost any corpus. I really should clean up things like the string cleaning routines, but it worked for class, and that’s what actually matters.
Python Pidgin Dbus Monitor
This is a script that registers a callback with Pidgin’s Dbus interface, and then sends a message in response whenever anyone sends an IM. I’m using it for a chatbot, but it could easily be extended to do things like switch X10 light controllers on and off, get the state of hardware connected to the target computer, and so forth. Pidgin has to be running and configured to use Dbus, but it does that by default.
'''
Created on Nov 18, 2011
Watches pidgin over Dbus and responds to incoming messages.
'''
import dbus
from dbus.mainloop.glib import DBusGMainLoop
import gobject
class StupidResponder():
def getResponse(self, message):
#This is where you would do something clever to come up with a response
return "Insect! I cannot bear your words! They are TOO TINY!"
def got_msg_cb(account, sender, message, conversation, flags):
purple.PurpleConvImSend(purple.PurpleConvIm(conversation), responder.getResponse(message))
if __name__ == '__main__':
#load a response generator
responder = StupidResponder()
#Connect to pidgin on Dbus
main_loop = DBusGMainLoop()
session_bus = dbus.SessionBus(mainloop = main_loop)
obj = session_bus.get_object("im.pidgin.purple.PurpleService", "/im/pidgin/purple/PurpleObject")
purple = dbus.Interface(obj, "im.pidgin.purple.PurpleInterface")
#Add the callback
session_bus.add_signal_receiver(got_msg_cb, dbus_interface="im.pidgin.purple.PurpleInterface", signal_name="ReceivedImMsg")
#Listen
loop = gobject.MainLoop()
loop.run()
Crazy Talk
This is a program that I wrote about ten years ago, to generate nonsense from a given input text. It builds a statistical model of the input text, which allows it to determine, given any two words, what the most likely third word is. Then it can use the last two words of those three to pick a new word, and so on. Since it doesn’t always pick the most likely word, but selects randomly from all options based on likelihood, it tends to create abrupt switches of concepts around short phrases like “it to” or “in the”.
For bonus points, it posts to a Blogger blog, assuming they haven’t changed their API.
It’s written in Perl, and I assume still works. If not, updating it to Python would be fun, and a good excuse for me to practice my Python.
Recent Comments