Waveform is a class to generate waveform images from audio files. You can combine it with jPlayer to make a soundcloud.com style MP3 player. It also comes with a handy CLI you can use to generate waveform images on the command line.
Build libsndfile (http://www.mega-nerd.com/libsndfile/), or install it via
sudo apt-get install libsndfile1-dev), or
libsndfile in macports.
$ sudo gem install waveform
You might also want to, but don't have to:
$ sudo gem install oily_png
to make things a bit faster, and:
$ sudo apt-get install ffmpeg
if you want Waveform to convert non WAV audio for you.
See Requirements below for more info
$ waveform song.mp3 waveform.png
There are some nifty options you can supply to switch things up:
-W sets the width (in pixels) of the waveform image. -H sets the height (in pixels). -c sets the color used to draw the waveform (in hex, can also use 'transparent'). -b sets the background color to draw the waveform on (in hex, and can use 'transparent' as well). -m sets the method used to sample the source audio file, it can either be 'peak' or 'rms'. 'peak' is probably what you want because it looks cooler, but 'rms' is closer to what you actually hear.
There are also some less-nifty options:
-q will generate your waveform without printing out a bunch of stuff. -h will print out a help screen with all this info. -F will automatically overwrite destination file.
Generating a small waveform "cut out" of a white background is pretty useful, then you can overlay it on a web-gradient on the website for your new startup and it will look really cool. To make it you could use:
$ waveform -W900 -H140 -ctransparent -b#ffffff Motley\ Crüe/Kickstart\ my\ Heart.mp3 sweet_waveforms/Kickstart\ my\ Heart.png
Usage in code
The CLI is really just a thin wrapper around the Waveform class, which you can also use in your programs for reasons I haven't thought of. The Waveform class takes pretty much the same options as the CLI when generating waveforms.
The gem version, not the old outdated library listed on RAA.
a wrapper for
libsndfile, on my Ubuntu 10.04LTS VM I installed the necessary
libs to build
sudo apt-get install libsndfile1-dev.
chunky_png is a pure ruby (!) PNG manipulation library. Caveat to this
requirement is that if you also install
oily_png you will get better
performance as it uses some C code, and C code is fast.
You only need
ffmpeg if you plan to generate waveforms from files that aren't
already WAVs (like MP3, or M4A). On my same Ubuntu VM I installed it via
sudo apt-get install ffmpeg and it was able to convert MP3 and M4A files out of the
box. The formats you can convert depend on which decoders you have installed.
If you don't want to install ffmpeg, you could also use one of the many audio format converters to convert your files to WAV before generating waveforms.
Or you could be all retro and use WAV audio for everything in the first place.
contest gem &
ffmpeg (to test conversion), run via:
Sample sound file is in Public Domain from soundbible.com. http://soundbible.com/1598-Electronic-Chime.html
http://pscode.org/javadoc/src-html/org/pscode/ui/audiotrace/AudioPlotPanel.html#line.996 http://github.com/pangdudu/rude/blob/master/lib/waveform_narray_testing.rb http://stackoverflow.com/questions/1931952/asp-net-create-waveform-image-from-mp3 http://codeidol.com/java/swing/Audio/Build-an-Audio-Waveform-Display
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