DRC-Meter

Dynamic Range Compression Meter

Measure the consequences of the Loudness War on your music files

Overview

DRC-Meter is a small software application that can be used to approximate the amount of dynamic range compression that has been applied to a digital audio file. It can hence be used to measure the effects of the loudness war. It can be used on any .mp3, .m4a, .wav, .aif, .flac or .ogg audio file. It will not affect the files in any way.

Note that dynamic range compression has nothing to do with data compression (such as mp3 encoding). If you do not know the difference between the two, you probably do not need this tool.

Only compression of the microdynamics are measured. Compression of the macrodynamics (if any) are ignored.

Requirements

A Java Runtime Environment (JRE) version 5 or greater. the latest JRE can be downloaded for Windows or Linux at http://www.java.com (it's free!). Mac OS X users should download it through software update. Note that it is installed by default starting from Mac OS 10.5 and below.

Download

DRC-Meter.zip (version 1.0.3, 1.68 Mb)

Usage
Graphical user interface

Double-click on DRC-Meter.jar to launch the application.

Just choose one or more audio files in the file dialog that opens and click ok. You can also choose folders, in which case the application will recursively scan the folders for all supported audio files it can find. The results of the analysis are displayed in the main window. Each audio file may require some seconds to some minutes to be analyzed.

Command line interface

Lauch the application using

    java -jar DRC-Meter.jar <file> [<file> ...]
   
where <file> is an audio file, or a folder containing audio files. The results of the analysis are printed directly on the console.

Note: lauching the application from the command line without specifying any file will launch the graphical user interface.

Understanding the results

The amount of dynamic range compression is given for each audio file by a number. The greater the number, the higher the dynamic range compression (Note well: this measures the dynamic range compression and not the dynamic range). Here's how I interpret the results (your interpretation may will vary as dynamic range compression is highly subjective):

Again this is about dynamic range compression and not about data compression.

Important

The applications uses heuristics and produces an approximation of the dynamic range compression. Never take any of the results firmly. Furthermore, DRC-Meter has a limited precision: when applied on several audio files with exactly the same amount of dynamic range compression, the results typically have a variation of +/- 1.0, and results with +/- 2.0 or more occasionally happen. Hence if for example the average result of an album is greater by 3 or 4 than the average result of another album, you can be pretty sure that the former has been more compressed than the later. However, if a single song scores for example 1.5 more than another one, it may not mean anything at all.

More generally, the results will almost never magically tell you the exact parameters of the compressor plugins that was used to compress the dynamics, and may even be quite far from the real values. The results are only comparable to what you can infer by carefully looking at the audio file's waveform. If you know how effective it is to look at an audio waveform, you know how effective DRC-Meter is. Note however that:

Note that DRC-Meter measures dynamic range compression. This is not the same as data compression such as the bitrate of an mp3 file. It has in fact nothing to do with mp3 encoding in any way.

Limitations

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