Audio Watermarking Tools (AWT) of www.audiowatermarking.info are shareware utilities for embedding (and extracting) short data payload within audio streams (wave files). The tools are distributed as a package of Win32 console utilities running on Microsoft Windows 7/Vista/XP/NT/2000/Server; x86 and x64 versions of the binaries are available.
The watermark is extremely robust. It survives almost all kinds of audio conversions like transcoding using MP3, Ogg Vorbis and other lossy coders, acoustic coupling (transducing via air), effect processing, from a simple EQ to an extreme dynamic range compression, reverberation, echo, and more. AWT is free to try.
AWT package is free to try. Evaluation (demo) version of AWT with limited functionality is available and can be downloaded absolutely free. Despite its limited functionality, the demo package offers enough flexibility to perform a variety of performance tests so that you can decide whether AWT suits your needs before buying a fully functional version.
AWT at a glance
AWT algorithm implements so called "strict watermarking" approach, meaning that the original (non-watermarked) audio stream is required to extract the watermark from the watermarked stream.
The watermark is extremely robust. Details and examples are on this page.
AWT encoder operates with wave PCM audio files of almost any feasible format - mono/stereo, with sampling rates from 8 up to 192 KHz, and amplitude resolution of 8/16/24/32 bits.
Virtually any watermarking payload size is supported. Feasible payload sizes range from 1 to 10 bytes.
With default parameters, watermarking data rate is 7 bps for 1-byte payload, 10 bps for 2-byte payload, 12 bps for 4-byte payload, and 14 bps for 8-byte payload. Thus, the watermarking rate increases with the increase of payload size due to some constant overhead for each copy of the watermarking payload.
The watermarking algorithm works in a time domain. The overall idea behind the algorithm is in embedding a binary watermarking payload within a carrier audio signal in a time domain by time-shifting the carrier signal blocks in one or several frequency sub-bands. The algorithm is patent pending*.
The algorithm can be applied to all kinds of audio data. Typical examples: music (pop, jazz, classics, rock, whatever else) and speech recordings.
Each copy of the AWT binaries contains a unique numeric identifier that is used both during the encoding and decoding. This security feature prevents one user from extracting or even detecting a watermark in output files of another user.