Methods, apparatus, systems, and articles of manufacture to improve watermark detection in acoustic environments are disclosed. An example apparatus includes at least one memory, instructions in the apparatus, and processor circuitry to execute and/or instantiate the instructions to encode a first symbol in a media file at a first symbol position on a first encoding layer of a multilayered watermark, and encode a second symbol in the media file at a second symbol position on a second encoding layer of the multilayered watermark, the first encoding layer and the second encoding layer including a plurality of symbol positions, one or more of the plurality of the symbol positions on at least one of the first encoding layer or the second encoding layer to be empty.

A processing method of a sound watermark and a speech communication system are provided. Multiple sinewave signals are generated. Frequencies of the sinewave signals are different from each other, and the sinewave signals belong to a high-frequency sound signal. A watermark pattern is mapped into a time-frequency diagram, to form a watermark sound signal. Two dimensions of the watermark pattern in a two-dimensional coordinate system respectively correspond to a time axis and a frequency axis in the time-frequency diagram. Each of multiple audio frames on the time axis corresponds to the sinewave signals with different frequencies on the frequency axis. A speech signal and the watermark sound signal are synthesized in a time domain to generate a watermark-embedded signal. Accordingly, a sound watermark may be embedded in real-time.

A processing method of a sound watermark and a speech communication system are provided. Multiple sinewave signals are generated. Frequencies of the sinewave signals are different from each other, and the sinewave signals belong to a high-frequency sound signal. A watermark pattern is mapped into a time-frequency diagram, to form a watermark sound signal. Two dimensions of the watermark pattern in a two-dimensional coordinate system respectively correspond to a time axis and a frequency axis in the time-frequency diagram. Each of multiple audio frames on the time axis corresponds to the sinewave signals with different frequencies on the frequency axis. A speech signal and the watermark sound signal are synthesized in a time domain to generate a watermark-embedded signal. Accordingly, a sound watermark may be embedded in real-time.

Methods and apparatus for performing variable block length watermarking of media are disclosed. Example apparatus include means for evaluating a masking ability of a first audio block; means selecting a first frequency to represent a first code, the means for selecting to (i) select the first frequency selected from a first set of frequencies that are detectable when performing a frequency transformation using a first block length, but are not detectable when performing a frequency transformation using a second block length, and (ii) select a second frequency to represent a second code, the second frequency selected from a second set of frequencies that are detectable when performing a frequency transformation using the second block length; means for synthesizing a first signal having the first frequency with the masking ability of the first audio block; and means for combining the first signal with the first audio block.

Methods and apparatus for performing variable block length watermarking of media are disclosed. Example apparatus include means for evaluating a masking ability of a first audio block; means selecting a first frequency to represent a first code, the means for selecting to (i) select the first frequency selected from a first set of frequencies that are detectable when performing a frequency transformation using a first block length, but are not detectable when performing a frequency transformation using a second block length, and (ii) select a second frequency to represent a second code, the second frequency selected from a second set of frequencies that are detectable when performing a frequency transformation using the second block length; means for synthesizing a first signal having the first frequency with the masking ability of the first audio block; and means for combining the first signal with the first audio block.

A system and a method of data communication between a first computing device, associated with a first user, and at least one second computing device associated with a second user may include: receiving, by the first computing device, one or more data elements pertaining to details of a transaction request from the second computing device, via a voice channel; extracting said transaction request details by the first computing device; transmitting, by the first computing device, one or more authentication data elements of an electronic wallet module, comprised in the first computing device, to the second computing device, via the voice channel; and carrying out the requested transaction by the first computing device, based on the extracted transaction request details and the electronic wallet authentication data.

The invention provides a concept for combined dynamic range compression and guided clipping prevention for audio devices. An audio decoder for decoding an audio bitstream and a metadata bitstream related to the audio bitstream according to the concept includes an audio processing chain including a plurality of adjustment stages including a dynamic range control stage for adjusting a dynamic range of the audio output signal and a guided clipping prevention stage for preventing clipping of the audio output signal; and a metadata decoder configured to receive the metadata bitstream and to extract dynamic range control gain sequences and guided clipping prevention gain sequences from the metadata bitstream, at least a part of the dynamic range control gain sequences being supplied to the dynamic range control stage, and at least a part of the guided clipping prevention gain sequences being supplied to the guided clipping prevention stage.

The invention provides a concept for combined dynamic range compression and guided clipping prevention for audio devices. An audio decoder for decoding an audio bitstream and a metadata bitstream related to the audio bitstream according to the concept includes an audio processing chain including a plurality of adjustment stages including a dynamic range control stage for adjusting a dynamic range of the audio output signal and a guided clipping prevention stage for preventing clipping of the audio output signal; and a metadata decoder configured to receive the metadata bitstream and to extract dynamic range control gain sequences and guided clipping prevention gain sequences from the metadata bitstream, at least a part of the dynamic range control gain sequences being supplied to the dynamic range control stage, and at least a part of the guided clipping prevention gain sequences being supplied to the guided clipping prevention stage.

A computer-implemented method for detecting and concealing confidential communications is disclosed. The computer-implemented method includes determining an audio output source used by a participant of an audio conference is unidentifiable. The computer-implemented method further includes responsive to determining that the audio output source used by the participant of the audio conference is unidentifiable, transmitting a high frequency signal via audio conference software used by the participant to conduct the audio conference. The computer-implemented method further includes responsive to detecting the high frequency signal via a microphone of a user device used by the participant to listen to the audio conference, determining that the participant is using a speaker to listen to the audio conference.

A computer-implemented method for detecting and concealing confidential communications is disclosed. The computer-implemented method includes determining an audio output source used by a participant of an audio conference is unidentifiable. The computer-implemented method further includes responsive to determining that the audio output source used by the participant of the audio conference is unidentifiable, transmitting a high frequency signal via audio conference software used by the participant to conduct the audio conference. The computer-implemented method further includes responsive to detecting the high frequency signal via a microphone of a user device used by the participant to listen to the audio conference, determining that the participant is using a speaker to listen to the audio conference.