Audio Watermarking & Audio Fngerprinting

The two leading methodology are audio fingerprinting and audio watermarking.

Audio Fingerprinting

Audio fingerprinting generates unique fingerprints from the content itself. Fingerprinting techniques work regardless of content format, codec, bitrate and compression techniques. This makes it possible to use across networks and channels. Therefore, it is widely used for interactive TV, second screen application and content monitoring sectors. Popular apps like ShazamYouTubeFacebook, ThetakeWechat and Weibo are using audio fingerprinting methodology to recognize the contented played from a TV and trigger additional features like votes, lottery, topic or purchase.

Audio Watermarking

In contrast to fingerprinting, audio watermarking requires inserting digital tags containing information about the content into the content itself, prior to distribution. For example, a broadcast encoder might insert a watermark every few seconds that could be used to identify to broadcast channel, program id, and time stamp. The watermark is normally inaudible or invisible to the users. Terminal devices like phones or tablets read the watermarks instead of actually recognizing the played content. Watermarking technology is utilized in media protection field to trace where the illegal copies originate. (From Wikipedia)