CarrierWave::AudioWaveform

Generate waveform images from audio files within Carrierwave

Add this line to your application's Gemfile:

gem 'carrierwave-audio-waveform'

And then execute:

$ bundle

Or install it yourself as:

$ gem install carrierwave-audio-waveform

First, install SoX on your local environment and production servers.

Second, install Audio Waveform on your local environment and production servers if you plan to generate waveform data rather than an image.

Lastly, include CarrierWave::AudioWaveform in your CarrierWave uploader class:

class AudioUploader < CarrierWave::Uploader::Base
  include CarrierWave::AudioWaveform
end

See the sections below for specific implementations.

To generate a PNG image:

class AudioUploader < CarrierWave::Uploader::Base
  include CarrierWave::AudioWaveform
  
  version :waveform_image do
    process :waveform => [{
      background_color: :transparent,
      color: "#666",
      sample_width: 2,
      gap_width: 2,
      height: 75,
      width: 1500
    }]

    def full_filename(for_file)
      "#{super.chomp(File.extname(super))}.png"
    end
  end
end

Parameter	Description	Permitted Values	Default
background_color	The image's background color	String (hex value) or :transparent	:transparent
color	The waveform's color; Only valid when type is :png	String (hex value)	"#00ccff" ( Cyan)
sample_width	Integer specifying the sample width. If this is specified, there will be gaps (minimum of 1px wide, as specified by gap_width) between samples that are this wide in pixels.	Integer >= 1	nil
gap_width	Integer specifying the width of the gaps between samples. If sample_width is specified, this will be the size of the gaps between samples in pixels.	Integer >= 1	nil
height	The image's height	Integer	280
width	The image's width	Integer	1800
auto_width	Milliseconds per pixel. This will overwrite the width of the final waveform image depending on the length of the audio file. Example: 100 => 1 pixel per 100 msec; a one minute audio file will result in a width of 600 pixels	Integer	nil
method	The method used to read sample frames, :peak or :rms. Peak is the norm. It uses the maximum amplitude per sample to generate the waveform, so the waveform looks more dynamic. RMS is more of an average, and the waveform isn't as jerky.	Symbol (:peak or :rms)	:peak
logger	IOStream to log progress	IOStream	nil

Note: Make sure to install Audio Waveform on your local environment and production servers if you plan to generate waveform data.

To generate an array of waveform data:

class AudioUploader < CarrierWave::Uploader::Base
  include CarrierWave::AudioWaveform
  
  version :waveform_peak_data do
    process :waveform_data => [{
      convert_to_extension_before_processing: :wav,
      pixels_per_second: 10
    }]

    def full_filename(for_file)
      "#{super.chomp(File.extname(super))}.json"
    end
  end
end

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request