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Revision as of 16:00, 18 April 2021 by Jo2 (talk | contribs) (added detailed instructions for installing with Linux)
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Checker: An Audio File Validator for LibriVox Contributions

Checker, showing validation of an audio file

Checker is an open source tool that looks for common problems with Librivox recordings.

You can download the tool from the developer's website, here. The current version is release 0.96i, dated 11 January 2019.

What does Checker do?

Checker looks for common problems with your Librivox audio recordings. It can save you time by checking your file for common technical issues before you go to the trouble of uploading it.

The program checks many technical features of your file. It can find problems with volume, MP3 encoding options, audio format, metadata (ID3 tags), and file naming conventions.

It does not check the content of the recording (such as reading the wrong word), nor the quality of your performance.

How to use Checker

To use Checker, drag-and-drop MP3 files (or a folder or ZIP archive) onto the window, then wait for it to analyze them. Once done, click a file name to see a report of any issues that it found. The report will either state that the file “passed” or else list any issues as errors or warnings. Errors are serious problems that should be fixed before uploading the file. A warning is less serious, or in some cases a potential problem that Checker is not sure about.

For a video on using Checker to review the decibel level of your MP3: click here


Checker is written in Java, and runs on many popular platforms including Windows, MacOS and Linux.

Detailed Instructions for installing Checker on Linux

To install this useful utility in Linux,the programmer's advice is succinct: Download and unzip the file, then run the checker script to start the application.

Here are some detailed instructions posted in the forum by a Linux user.

1. Go to the Checker page -

2. Click the 'Download for Linux' link

3. Save the compressed file - checker-unix-0.96.tar.gz - to [whatever folder you choose for such Downloads]

3. Extract checker-unix-0.96.tar.gz - you can probably just right click on the file and choose "Extract".

4. The "checker" script that you have to run has been extracted in a folder of the same name along with other files.

5. Open the "checker" script in a text editor and follow the programmer's instructions - Uncomment the following line ..... (That is, just edit out the # at the beginning of the two lines that begin "INSTALL4J")

5. Open a terminal and as root (su or sudo) give yourself permission to run 'checker' by typing chmod 777 path-to--checker . (I chose the easy option of giving everybody permission to do anything by specifying '777' ).

6. Now - Run checker! You do this by navigating to the folder containing the 'checker' script, opening a command line and typing: ./checker

7. If, like mine, your Java is a recent version, running the checker script will give you the message that:

The version of the JVM must be at least 1.6 and at most 1.8. Please define INSTALL4J_JAVA_HOME to point to a suitable JVM

In which case, you can google "openjdk-8-jre", download and install it with your package manager,and you will get an earlier JVM (Java Virtual Machine) which will work with Checker. I uninstalled my openjdk-11-jre package first but I don't think that is necessary.

And now you run checker again and all is well!

8. For anybody using the KDE Plasma Desktop Environment, you can add Checker to the application launcher and give it a nice icon:

Right click on the Application Launcher. Edit applications... Mark the folder you want it in, e.g. Utilities. Click on New. Fill in the name you want. Add the actual command and click on the square next to name to change the icon. Click Save.

You need to have Java running on your computer in order to use Checker. If you are installing Checker to Windows or to MacOS, the Checker installer will automatically try to install Java for you if necessary, but if that fails you can also install it yourself.

Further installation instructions can be found on the download page.

If you run into problems, make sure you have not disabled Java in your browser.