Detection of signal modifications in audio streams with embedded code
AssigneeNielsen Media Research, Inc.
InventorVenugopal Srinivasan
Life of this patent
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Abstract
An encoder transforms at least a portion of a signal, counts the resulting transform coefficients having a zero value, and encodes the signal with the zero count. A decoder decodes the signal in order to recover the zero count. The decoder may also determine its own zero count of the signal as received and may compare the zero count that it determines to the recovered zero count. The decoder may be arranged to detect compression/decompression based upon results from the comparison, and/or the decoder may be arranged to prevent use of a device based upon results from the comparison.
Claims77
An encoder having an input and an output, wherein the input receives a signal, wherein the encoder calculates a zero count of at least a portion of the signal and encodes the signal with the calculated zero count, and wherein the output carries the encoded signal.
A decoder having an input and an output, wherein the input receives a signal, wherein the decoder decodes the signal so as to read a zero count code from the received signal, and wherein the output carries a signal based upon the decoded zero count code.
A method of encoding a signal comprising:
- a) performing a transform of the signal to produce coefficients;
- b) counting those coefficients having a predetermined value;
- and,
- c) encoding the signal with the count.
A method of decoding a received signal comprising:
- a) decoding the received signal so as to read a coefficient value count code from the received signal;
- b) performing a transform of the received signal to produce transform coefficients;
- c) counting those transform coefficients having a predetermined value;
- and,
- d) comparing the coefficient value count contained in the coefficient value count code to the transform coefficient count.
An electrical signal containing a count code related to a count of coefficients resulting from a transform of at least a portion of the electrical signal.
Dependencies are inferred from the claim text.