Methods and apparatus to perform audio watermarking and watermark detection and extraction
Methods and apparatus to audio watermarking and watermark detection and extracted are described herein. An example method includes receiving a media content signal, sampling the media content signal to generate samples, storing the samples in a buffer, determining a first sequence of samples in the buffer, determining a second sequence of samples in the buffer, wherein the second sequence of samples is of substantially equal length as the first sequence of samples, calculating an average of the first sequence of samples and the second sequence of samples to generate an average sequence of samples, extracting an identifier from the average sequence of samples, and storing the identifier in a tangible memory.
1. A computing system comprising a processor and a memory, the computing system configured to perform a set of acts comprising:
obtaining a first sequence of samples of an audio signal;
obtaining a second sequence of samples of the audio signal;
averaging samples of the first sequence of samples with respective samples of the second sequence of samples to generate an average sequence of samples;
extracting an identifier from the average sequence of samples; and
storing the identifier.
2. The computing system of claim 1 , wherein obtaining the first sequence of samples comprises sampling the audio signal.
3. The computing system of claim 1 , wherein extracting the identifier comprises:
identifying emphasized code frequencies; and
determining, based on the emphasized code frequencies, a symbol encoded in the audio signal.
4. The computing system of claim 3 , wherein the set of acts further comprises converting the average sequence of samples from time-based information into frequency-based information.
5. The computing system of claim 3 , wherein determining the symbol comprises using a look up table to map the emphasized code frequencies to the symbol.
6. The computing system of claim 1 , wherein obtaining the second sequence of symbols comprises obtaining a second sequence of samples that is separated in time from the first sequence of samples by a repetition period.
7. The computing system of claim 6 , wherein the identifier is repeated in the audio signal in accordance with the repetition period.
8. A non-transitory computer-readable medium having stored therein instructions that, upon execution by one or more processors, cause a computing system to perform a set of acts comprising:
obtaining a first sequence of samples of an audio signal;
obtaining a second sequence of samples of the audio signal;
averaging samples of the first sequence of samples with respective samples of the second sequence of samples to generate an average sequence of samples;
extracting an identifier from the average sequence of samples; and
storing the identifier in a memory.
9. The non-transitory computer-readable medium of claim 8 , wherein obtaining the first sequence of samples comprises sampling the audio signal.
10. The non-transitory computer-readable medium of claim 8 , wherein extracting the identifier comprises:
identifying emphasized code frequencies; and
determining, based on the emphasized code frequencies, a symbol encoded in the audio signal.
11. The non-transitory computer-readable medium of claim 10 , wherein the set of acts further comprises converting the average sequence of samples from time-based information into frequency-based information.
12. The non-transitory computer-readable medium of claim 10 , wherein determining the symbol comprises using a look up table to map the emphasized code frequencies to the symbol.
13. The non-transitory computer-readable medium of claim 8 , wherein obtaining the second sequence of symbols comprises obtaining a second sequence of samples that is separated in time from the first sequence of samples by a repetition period.
14. The non-transitory computer-readable medium of claim 13 , wherein the identifier is repeated in the audio signal in accordance with the repetition period.
15. A method comprising:
obtaining, by a computing system, a first sequence of samples of an audio signal;
obtaining, by the computing system, a second sequence of samples of the audio signal;
averaging, by the computing system, samples of the first sequence of samples with respective samples of the second sequence of samples to generate an average sequence of samples;
extracting, by the computing system, an identifier from the average sequence of samples; and
storing, by the computing system, the identifier in a memory.
16. The method of claim 15 , wherein obtaining the first sequence of samples comprises sampling the audio signal.
17. The method of claim 15 , wherein extracting the identifier comprises:
identifying emphasized code frequencies; and
determining, based on the emphasized code frequencies, a symbol encoded in the audio signal.
18. The method of claim 17 , further comprising converting the average sequence of samples from time-based information into frequency-based information.
19. The method of claim 17 , wherein determining the symbol comprises using a look up table to map the emphasized code frequencies to the symbol.
20. The method of claim 15 , wherein obtaining the second sequence of symbols comprises obtaining a second sequence of samples that is separated in time from the first sequence of samples by a repetition period.