An audio watermark addition method is provided, and includes: A playback terminal obtains first audio in real time, embeds an audio watermark into the first audio, where the audio watermark is associated with the playback terminal; and plays the first audio embedded with the audio watermark.

An audio watermark addition method is provided, and includes: A playback terminal obtains first audio in real time, embeds an audio watermark into the first audio, where the audio watermark is associated with the playback terminal; and plays the first audio embedded with the audio watermark.

In one example, a method for inserting a digital watermark in a signal includes obtaining the signal comprising a plurality of frames, inserting a first digital watermark in a first frame of the plurality of frames, inserting a second digital watermark in a second frame of the plurality of frames, wherein the second digital watermark differs from the first digital watermark in at least one way selected from a group of: a location within a respective frame, a number of bits, a pattern of bits, and a number of bits of a noise, and outputting a watermarked signal including the first digital watermark in the first frame and the second digital watermark in the second frame.

In one example, a method for inserting a digital watermark in a signal includes obtaining the signal comprising a plurality of frames, inserting a first digital watermark in a first frame of the plurality of frames, inserting a second digital watermark in a second frame of the plurality of frames, wherein the second digital watermark differs from the first digital watermark in at least one way selected from a group of: a location within a respective frame, a number of bits, a pattern of bits, and a number of bits of a noise, and outputting a watermarked signal including the first digital watermark in the first frame and the second digital watermark in the second frame.

The invention resides in a method of placing a code, having a plurality of digits, in original data having media data including audio data, such as a music video, piece of music or music track, to produce coded data. The method determining an area of original data where a digit of the code can be placed to inhibit detection using a placement criteria. A coding strategy determines at least one of the format or location of a digit of the code in coded data. The or each digit of the code has a melodic or sympathetic relationship with a characteristic, such as an audio characteristic, of the corresponding original data in the at the location in which it is placed. Digits are added to the original data and outputting coded data. Similarly, the invention resides in a method for decoding and devices and systems for implementing said methods.

The invention resides in a method of placing a code, having a plurality of digits, in original data having media data including audio data, such as a music video, piece of music or music track, to produce coded data. The method determining an area of original data where a digit of the code can be placed to inhibit detection using a placement criteria. A coding strategy determines at least one of the format or location of a digit of the code in coded data. The or each digit of the code has a melodic or sympathetic relationship with a characteristic, such as an audio characteristic, of the corresponding original data in the at the location in which it is placed. Digits are added to the original data and outputting coded data. Similarly, the invention resides in a method for decoding and devices and systems for implementing said methods.

Methods, apparatus and articles of manufacture (e.g., computer readable media) to detect watermark modifications are disclosed. Example apparatus disclosed herein include means for encoding a first watermark in a first media signal obtained from an output of a media device to obtain a second media signal encoded with the first watermark and a second watermark, the second watermark already encoded in the first media signal obtained from the output of the media device. Disclosed example apparatus also include means for decoding the first watermark and the second watermark from the second media signal to determine a first metric corresponding to the first watermark and a second metric corresponding to the second watermark. Disclosed example apparatus further include means for outputting, based on the first metric and the second metric, an indication of whether the second watermark has been modified.

Methods, apparatus and articles of manufacture (e.g., computer readable media) to detect watermark modifications are disclosed. Example apparatus disclosed herein include means for encoding a first watermark in a first media signal obtained from an output of a media device to obtain a second media signal encoded with the first watermark and a second watermark, the second watermark already encoded in the first media signal obtained from the output of the media device. Disclosed example apparatus also include means for decoding the first watermark and the second watermark from the second media signal to determine a first metric corresponding to the first watermark and a second metric corresponding to the second watermark. Disclosed example apparatus further include means for outputting, based on the first metric and the second metric, an indication of whether the second watermark has been modified.

Example apparatus disclosed herein are to detect a first watermark embedded in an audio stream associated with media, the first watermark embedded and detected based on a first watermarking technique; and detect a second watermark embedded in the audio stream, the second watermark embedded and detected based on a second watermarking technique. Disclosed example apparatus are also to assign the first watermark to a first monitoring track and to a second monitoring track, the first monitoring track limited to watermarks embedded in the audio stream based on the first watermarking technique, the second monitoring track limited to watermarks embedded in the audio stream based on any of the first or second watermarking techniques; group the first and second watermarks to form a media detection event when the second watermark is assigned to the second monitoring track; and cause transmission of the media detection event to a data collection facility.

A method and a system for augmenting an audio feed for inclusion of data therein suitable for determining an identity of a human assessor are provided. The method comprises: receiving the audio feed; receiving an indication of identity of the human assessor to whom the audio feed is to be transmitted, the indication of identity being representable by a unique sequence of bits; generating, based on the unique sequence of bits, an identity watermark associated with the human assessor to be included in the audio feed to generate an augmented audio feed, by modifying the audio signal to have predetermined energy level at each of at least two different frequency levels to indicate presence of the given bit of the unique sequence of bits associated with the human assessor in the augmented audio feed; and transmit the augmented audio feed to an electronic device associated with the human assessor.