Eym Audio Watermarking Windows application v1.1
The EyM Audio Watermarking tools are shareware utilities that are offered “as is”. This simple Windows application allows its user to embed (resp. retrieve) a short data payload within (resp. from) 16-bit PCM audio wav files. This shareware is intended to target small to medium size applications that may require an audio watermark. Although proof of ownership, tracking and copy deterrence might be the most popular applications of digital watermarks this shareware provides complete control over the nature of the data you might decide to embed in an audio recording. From the application’s point of view your payload is just a series of byte values represented as a string of hexadecimal characters.
For the sake of simplicity this Windows application processes one file at a time. As an alternative to this GUI, command line utilities are also available. These require no specific installation process and are more suitable for applications that require either batch processes or the integration within an existing workflow.
· Reading a watermark from a WAV file
· Sharing your private layer code
Application overview
The first time you run the application or each time you launch it as a demo, you will be prompted with a registration dialog that will give you an opportunity to purchase and/or enter a license key you’ve purchased.
Initial registration dialog
You may dismiss this dialog by pressing on the “Run as Demo” button. Even in its demo mode, the application will provide enough functionality for you to experiment with the underlying audio watermarking methodology.
Once you’ve dismissed this dialog you will then be shown the application’s main window in its idle mode.
EyM Audio Watermarking main window
As you will notice this application was design to be self-explanatory. Launching a watermark encoding or decoding job is done by selecting the appropriate item under the “File” menu. These can also be accessed through shortcuts: F1 for encoding and F2 for decoding.
You can also review and update your licensing status under the “Configurations” menu.
Watermarking a WAV file
From the main window you can either select “Encode File…” from the “File” menu or press the F1 key. This will open the application’s encoding dialog.
Encoding dialog
Source and destination files: You may either browse your system for the original WAV file you wish to encode or simply drag-and-drop it. As of this release this file must be a 16-bit PCM wav file. The number of channels can be arbitrary and the sampling rate must be one of the following: 48 kHz, 44.1 kHz, 32 kHz, 24 kHz, or 22.05 kHz. Once you’ve chosen your original audio file the application will automatically infer a suitable file name for the watermarked result. Of course you may change the name of the output file as you wish.
User data payload: Next you will be required to enter your payload. This payload should be provided as a string of hexadecimal {‘0’ – ‘9’, ‘A’ – ‘F’} characters. The actual payload that will be embedded in the audio file will have an integer number of bytes (i.e. an even number of hexadecimal digits) and it will be padded with an additional x0 if you provide an odd number of hexadecimals. If the size of the payload you enter exceeds the limit of your license, the “extra” portion of your payload is automatically replaced with xFF byte values. When running in demo mode (i.e. without a license key) this entire payload will be replaced by a matching number xF hexadecimal values. The application keeps track of your payload size and notifies you with any limitation you may have in a message below the text box.
Watermark layer: Use this control to tell the application whether you wish to use the shared public layer or your own private layer. When running in demo mode (i.e. without a license key), only the public layer will be available.
Time stamp: This bonus feature adds a 12-bit time code to the user payload. This time code is incremented in 15 seconds interval and it is embedded in a way that shouldn’t affect the recovery rate of the user payload noticeably. On the decoding side, there is no guarantee that this time stamp will be successfully recovered for every instance of the user payload that is found.
Watermark gain: This GUI allows its user to control the watermarking gain used during the encoding. The Default and recommended value is 1.0.
Once you have described your watermark encoding job you can press the “OK” button. This will dismiss this dialog and start the encoding process. The application’s main interface will then show you the job’s progress in real-time.
Watermark encoding progress
Once the job is done the main interface will remind you which file it just created.
Watermark encoding summary
At this point the application is ready for the next job.
Reading a watermark from a WAV file
From the main window you can either select “Decode File…” from the “File” menu or press the F2 key. This will open the application’s encoding dialog.
Decoding dialog
Source file: You may either browse your system for the watermarked WAV file you wish to analyze or simply drag-and-drop it. As of this release this file must be a 16-bit PCM wav file. The number of channels can be arbitrary and the sampling rate must be one of the following: 48 kHz, 44.1 kHz, 32 kHz, 24 kHz, 22.05 kHz, 16 kHz or 11.025 kHz.
Watermark layer: Use this control to tell the application whether you wish to use the shared public layer, your own private layer, or some other private layer for which you possess a layer code. For more information about private layer codes, the Sharing your private layer code section of this document. When running in demo mode (i.e. without a license key), only the public layer will be available.
Once you have described your watermark decoding job you can press the “OK” button. This will dismiss this dialog and start the encoding process. The application’s main interface will then show you the job’s progress in real-time.
Watermark decoding progress
Once the job is done the main interface will give you a summary of the decoding job. This will include a list of all watermark payloads that were detected.
Watermark decoding summary
At this point the application is ready for the next job.
Sharing your private layer code
Depending on your application you may want to allow others to read the contents of a private watermark you created while remaining the only one who can actually write watermark on your private layer.
In order to do this you will need to share your private layer code. It provides enough information for a user to read your mark but not enough to allow anyone to write a watermark on your private layer.
Your private layer code is the center subset of your license key so this assumes that you already have a valid EyM Audio Watermarking license key, which you’ve previously entered in the application’s registration dialog.
In order to retrieve your layer code, select the “License key…” item under the “Configurations” menu. This will open the application’s registration dialog and display your layer code if you’re already registered.
Watermark licensing dialog showing the current user’s layer code
You may copy this layer code from the dialog and share it with whomever you wish to authorize to read your private watermarks.