Devices for encoding and detecting a watermarked signal

Patent metadata

Field	Value
Publication number	US-9767823-B2
Application number	US-201113276115-A
Country	US
Kind code	B2
Filing date	Oct 18, 2011
Priority date	Feb 7, 2011
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A method for decoding a signal on an electronic device is described. The method includes receiving a signal. The method also includes extracting a bitstream from the signal. The method further includes performing watermark error checking on the bitstream for multiple frames. The method additionally includes determining whether watermark data is detected based on the watermark error checking. The method also includes decoding the bitstream to obtain a decoded second signal if the watermark data is not detected.

First claim

What is claimed is:

1. A method for decoding a signal on an electronic device, comprising:
receiving a signal that comprises a digital audio signal;
extracting a bitstream from the signal, wherein the bitstream comprises the digital audio signal;
performing watermark error checking using cyclic redundancy check (CRC) on the bitstream for multiple consecutive frames;
determining whether watermark data is detected based on the watermark error checking, based on an averaging scheme that comprises determining whether more than a number M of error check codes indicate correct data reception within a number N of said frames, wherein each of the error check codes corresponds to one of said frames, and wherein the watermark data is detected in all of the number N of said frames in a case that more than the number M of the error check codes indicate correct data reception;
selecting a first decoding mode in a case watermark data is detected or selecting a second decoding mode in a case watermark data is not detected, wherein the first decoding mode comprises modeling the watermark data to obtain a decoded first signal and decoding the bitstream to obtain a decoded second signal, and the second decoding mode comprises decoding the bitstream to obtain the decoded second signal without extracting watermark data;
performing decoding according to the first decoding mode in a case the first decoding mode is selected or the second decoding mode in a case the second decoding mode is selected; and
outputting a decoded second signal that is a second digital audio signal in a case that the watermark data is not detected or outputting a decoded first signal that is a first digital audio signal in a case that the watermark data is detected.

2. The method of claim 1 , wherein in the case that the watermark data is detected, the method further comprises:
determining whether an error is detected based on the watermark error checking; and
combining the decoded first signal and the decoded second signal in a case that no error is detected.

3. The method of claim 2 , wherein determining whether an error is detected is also based on performing error checking on the bitstream that is not specific to the watermark data.

4. The method of claim 2 , wherein in a case that an error is detected, the method further comprises:
concealing the decoded first signal to obtain an error concealment output; and
combining the error concealment output and the decoded second signal.

5. The method of claim 1 , wherein the bitstream is a narrowband bitstream and the watermark data comprises a layer of wideband information within the narrowband bitstream.

6. The method of claim 1 , wherein said frames are temporally distinct.

7. The method of claim 1 , wherein determining whether the watermark data is detected is performed in real time.

8. A method for encoding a watermarked signal on an electronic device, comprising:
obtaining a first signal and a second signal, wherein the first signal and the second signal comprise digital audio signals;
modeling the first signal to obtain watermark data;
adding a cyclic redundancy check (CRC) error check code to multiple consecutive frames of the watermark data, wherein the watermark data is indicated based on an averaging scheme that indicates watermark data in a case that more than a number M of error check codes indicate correct data reception within a number N of said frames, wherein each of the error check codes corresponds to one of said frames, wherein the watermark data is indicated in all of the number N of said frames in a case that more than the number M of the error check codes indicate correct data reception, and wherein adding the CRC error check code indicates a mode to decode the first signal and the second signal, and comprises adding an amount of error check code to said frames that is equal to or smaller than a predetermined number of error check bits per predetermined number of information bits;
encoding the second signal by embedding the watermark data into the second signal to obtain a watermarked second signal; and
outputting the watermarked second signal, wherein the watermarked second signal comprises a digital audio signal.

9. The method of claim 8 , wherein a proportion equal to or smaller than four error check bits per twenty information bits is the amount of error check code added to each of the said frames.

10. An electronic device configured for decoding a signal, comprising:
receiver circuitry configured to receive a signal that comprises a digital audio signal;
watermark detection circuitry configured to perform watermark error checking using cyclic redundancy check (CRC) on a bitstream extracted from the signal for multiple consecutive frames and to determine whether watermark data is detected based on the watermark error checking, based on an averaging scheme that comprises determining whether more than a number M of error check codes indicate correct data reception within a number N of said frames, wherein each of the error check codes corresponds to one of said frames, wherein the watermark data is detected in all of the number N of said frames in a case that more than the number M of the error check codes indicate correct data reception, and wherein the bitstream comprises the digital audio signal;
mode selection circuitry configured to select a first decoding mode in a case watermark data is detected or to select a second decoding mode in a case watermark data is not detected, wherein the first decoding mode comprises modeling the watermark data to obtain a decoded first signal and decoding the bitstream to obtain a decoded second signal, and the second decoding mode comprises decoding the bitstream to obtain the decoded second signal without extracting watermark data;
decoder circuitry configured to perform decoding according to the first decoding mode in a case the first decoding mode is selected or the second decoding mode in a case the second decoding mode is selected, wherein the decoder circuitry is configured to output a decoded second signal that is a second digital audio signal in a case that the watermark data is not detected or to output a decoded first signal that is a first digital audio signal in a case that the watermark data is detected.

11. The electronic device of claim 10 , wherein the watermark detection circuitry is configured to determine whether an error is detected based on the watermark error checking in the case that the watermark data is detected, and wherein the electronic device further comprises combining circuitry configured to combine the decoded first signal and the decoded second signal in a case that no error is detected.

12. The electronic device of claim 11 , wherein determining whether an error is detected is also based on performing, by error checking circuitry, error checking on the bitstream that is not specific to the watermark data.

13. The electronic device of claim 11 , further comprising error concealment circuitry configured to conceal the decoded first signal to obtain an error concealment output in a case that an error is detected, and wherein the combining circuitry combines the error concealment output and the decoded second signal in the case that an error is detected.

14. The electronic device of claim 10 , wherein the bitstream is a narrowband bitstream and the watermark data comprises a layer of wideband information within the narrowband bitstream.

15. The electronic device of claim 10 , wherein said frames are temporally distinct.

16. The electronic device of claim 10 , wherein determining whether the w

Assignees

• Villette Stephane Pierre
• Sinder Daniel J
• Qualcomm Inc

Inventors

• Villette Stephane Pierre
• Sinder Daniel J

Classifications

• G10L19/005

  Correction of errors induced by the transmission channel, if related to the coding algorithm · CPC title

• G10L19/018 Primary

  Audio watermarking, i.e. embedding inaudible data in the audio signal · CPC title

• G10L21/038 Primary

  using band spreading techniques · CPC title