Assessing quality of service using digital watermark information
View Patent ↗The disclosure details methods of measuring the quality of service of received media signals by analyzing digital watermarks embedded in such signals. The quality of a received video or audio signal can thereby be assessed without having the original version of the signal before transmission. Instead, the strength or quality of the embedded digital watermark is analyzed to determine the quality of the received signal. The degradation of a watermark signal is used to assess quality of service of signals, such as audio and video.
1. A method of measuring quality of service of a received media signal using a digital watermark embedded in the media signal, the media signal representing audio and/or video information, the method comprising:
receiving a media signal transmitted over a communication channel from a transmitter, wherein the channel from the transmitter is susceptible to occasional distortion, causing degradation in quality of service;
extracting a digital watermark from the received media signal; and
evaluating the extracted digital watermark relative to a reference digital watermark to measure degradation in quality of service of the media signal based on differences between the extracted and reference digital watermarks, wherein said evaluating act is performed by a combination of hardware and software, and includes comparing signal peaks of the media signal and the reference digital watermark.
2. The method of claim 1 wherein the signal peaks comprise frequency domain peaks.
3. A method of assessing quality of service of a received media signal, the media signal representing audio and/or video information, the method including:
applying a digital watermark decoding process to the received media signal to sense a sequence of soft data bits; and
applying said sequence of sensed bits to an error correction decoder, yielding an error-corrected message payload;
wherein the sequence of soft data bits that yielded the error-corrected message payload indicates the degree of degradation of the media signal since its original watermark encoding; and
wherein the applying acts are performed by a combination of hardware and software.
4. A method of encoding content with a digital watermark, the content comprising audio or video information, the method including:
generating key data though a process that includes applying a perceptual hashing function to the content;
using said key data to scramble or encrypt a message, the message comprising a watermark payload and corresponding CRC bits; and
encoding the content with said scrambled or encrypted message, to yield digitally watermarked content;
wherein the encoding act is performed by a combination of hardware and software.