Watermark insertion in frequency domain for audio encoding/decoding/transcoding

摘要

An audio processing device includes an initial processing module to generate a stream of frequency coefficients based on input audio data, a watermarking module to embed a digital watermark into the stream of frequency coefficients to generate a modified stream of frequency coefficients, and a final processing module to process the modified stream of frequency coefficients to generate output audio data. In some implementations, the input audio data comprises unencoded audio data, the initial processing module comprises a frequency domain transform module to perform a time-to-frequency domain transform to generate the unencoded audio data, and the output audio data is encoded audio data. In other instances, the input audio data comprises encoded audio data, the initial processing module comprises an initial decoding module to partially decode the encoded audio data to generate the stream of frequency coefficients, and the output audio data is decoded audio data.

主权项

1. A method comprising:
generating, at a processor of an audio processing device, a stream of frequency coefficients based on input audio data; embedding, at the processor, a digital watermark comprising a set of bit values into the stream of frequency coefficients to generate a modified stream of frequency coefficients, wherein embedding the digital watermark comprises:
for each bit value of the set of bit values, modifying a corresponding set of frequency coefficients of the stream of frequency coefficients based on the bit value to generate a corresponding set of the modified stream of frequency coefficients, wherein modifying the corresponding set of frequency coefficients based on the bit value comprises:
for each frequency coefficient of the set:performing a linear add of the frequency coefficient and a non-zero first value to generate a corresponding modified frequency coefficient responsive to the bit value comprising a one (1); andperforming a linear add of the frequency coefficient and a non-zero second value to generate a corresponding modified frequency coefficient responsive to the bit value comprising a zero (0);wherein the non-zero first value differs from the non-zero second value; and processing, at the processor, the modified stream of frequency coefficients to generate output audio data.