METHODS AND APPARATUS FOR PERFORMING VARIABLE BLOCK LENGTH WATERMARKING OF MEDIA

• US 20130268279A1
• Filed: 05/31/2013
• Published: 10/10/2013
• Est. Priority Date: 01/29/2008
• Status: Active Grant

• Current Assignee: The Nielsen Company LLC (MOOD Media Corporation)
• Original Assignee: The Nielsen Company LLC (MOOD Media Corporation)
• Inventors: Srinivasan, Venugopal, Topchy, Alexander
• Granted Patent: US 9,947,327 B2
• Time in Patent Office: Days
• US Class Current: 704/500
• CPC Class Codes: G10L 19/018 Audio watermarking, i.e. embedding inaudible data in the audio signal

Abstract

Methods and apparatus for performing variable block length watermarking of media are disclosed. An example method to encode auxiliary data in audio data comprises selecting a frequency based on a code, selecting a block size based on the code, a combination of the block size and the frequency to represent of the code, encoding the code in an audio stream according to the block size and the frequency, and transmitting the audio stream including the encoded code.

Claims

1. A method to encode auxiliary data in audio data, the method comprising:

selecting a frequency based on a code;

selecting a block size based on the code, a combination of the block size and the frequency to represent of the code;

encoding the code in an audio stream according to the block size and the frequency; and

transmitting the audio stream including the encoded code.

2. A method as defined in claim 1, further comprising padding the audio stream adjacent a portion of the audio stream encoded with the code with a number of unmodified samples corresponding to a difference between the block size and a predetermined block size.

3. A method as defined in claim 1, wherein the encoded code in the audio stream is visible at the frequency when the audio stream is decoded according to the block size and the encoded code is not visible at the frequency when the audio stream is decoded according to a different block size.

4. A method as defined in claim 1, further comprising accessing a lookup table based on the code to select the frequency and the block size.

5. An apparatus to encode auxiliary data in audio data, the apparatus comprising:

a selector to select a first frequency based on a code and select a block size based on the code, a combination of the block size and the first frequency to represent the code; and

a combiner to encode the code in an audio stream using the block size and the first frequency.

6. An apparatus as defined in claim 5, wherein the selector is to pad the audio stream adjacent a portion of the audio stream encoded with the code with a number unmodified samples corresponding to a difference between the first block size and a predetermined block size.

7. An apparatus as defined in claim 5, wherein the block size comprises a number of samples of the audio stream.

8. An apparatus as defined in claim 5, wherein the encoded code in the audio stream is visible at the first frequency when the audio stream is decoded using the block size and the encoded code is not visible at the first frequency when the audio stream is decoded using a second block size different than the first block size.

9. An apparatus as defined in claim 5, wherein the selector is to access a lookup table based on the code to select the frequency and the block size.

10. A machine readable physical storage structure comprising machine readable instructions which, when executed, cause a machine to at least:

select a frequency based on a code;

select a block size based on the code, a combination of the block size and the frequency to represent the code;

encode the code in an audio stream according to the block size and the frequency; and

transmit the audio stream including the encoded code.

11. A storage medium as defined in claim 10, wherein the instructions are further to cause the machine to pad the audio stream adjacent a portion of the audio stream encoded with the code with a number of unmodified samples corresponding to a difference between the block size and a predetermined block size.

12. A storage medium as defined in claim 10, wherein the encoded code in the audio stream is visible at the frequency when the audio stream is decoded according to the block size and the encoded code is not visible at the frequency when the audio stream is decoded according to a different block size.

13. A storage medium as defined in claim 10, wherein the instructions are further to cause the machine to access a lookup table based on the code to select the frequency and the block size.