Paperclip Normalize

THIS GEM IS NOT IMPLEMENTED. DO NOT USE IT YET!

Add an audio normalization processor to Paperclip.

This gem has been developed for use with Ubuntu. Your mileage may vary on other systems.

About Audio Normalization

Audio normalization is the process of adjusting the volume of a track to bring the loudness to a target level.

This is particularly useful for making sure that all of the files that you upload are audible without the user having to adjust the volume on a track-by-track basis.

Installation

Add to your Gemfile:

gem "paperclip-normalize", :git => "git://github.com/zmillman/paperclip-normalize.git"

normalize-audio must also be installed and Paperclip must have access to it.

sudo apt-get install normalize-audio

Usage

In your model:

class Podcast < ActiveRecord::Base
  has_attached_file :audio, :styles => {
      :release => {:format => 'mp3' }
    }, :processors => [:normalize]
end

This will produce a transcoded :release mp3 file with the audio normalized to 0dB.

Normalizing Video

paperclip-normalize also detects video file formats and works with FFMPEG to normalize the audio track. See paperclip-ffmpeg's documentation for information on installing and using FFMPEG.

In your model:

class Lesson
  has_attached_file :video, :styles => {
    :web => { :geometry => "640x480", :format => 'mp4' }
  }, :processors => [:ffmpeg, :normalize]
end

This will produce a transcoded :web mp4 with the audio track normalized to 0dB.

Kudos

Thanks to Chris Vaill for writing normalize-audio. None of this would work without him.