Detecting content of interest in streaming media

A client device configured to playback media and comprising a processor and a non-transitory, computer readable media configured to store instructions thereon that, when executed by the processor, cause the client device to perform operations, the operations comprising:

• receiving, by the client device, media content for playback;
• generating, by the client device, a first signature of the media content at a playback time, the first signature comprising a first set of frequency-amplitude pairs associated with the media content,
• wherein the client device applies a window function by multiplying scaled amplitudes with weighted multipliers from a first lookup table to generate tapered amplitudes,
• wherein the client device applies a discrete Fourier transform (DFT) to the tapered amplitudes using a second lookup table to generate outputs for frequency bins, the second lookup table containing first values for first trigonometric functions, and
• wherein the client device selects dominant output magnitudes from the outputs to generate the first set of frequency-amplitude pairs;
• transmitting, by the client device and to a server, the first signature, wherein the server is configured to detect that the media content includes a known content in response to the first signature matching a stored signature of the known content;
• receiving, by the client device and from the server, replacement content in response to the server detecting that the media content includes the known content;
• and
• playing, by the client device, the media content including the replacement content at the playback time.

An automated process executable on a client device to playback media content, the automated process comprising:

• generating, by the client device, a first signature of the media content at a playback time, the first signature comprising a first set of frequency-amplitude pairs associated with the media content,
• wherein the client device applies a window function using a first lookup table comprising first values of first trigonometric functions and a discrete Fourier transform (DFT) using a second lookup table comprising second values of second trigonometric functions to generate outputs for frequency bins, and
• wherein the client device selects dominant output magnitudes from the outputs to generate the first set of frequency-amplitude pairs;
• transmitting, by the client device and to a server, the first signature;
• receiving, by the client device, replacement content in response to transmitting the first signature to the server;
• and
• playing, by the client device, the media content including the replacement content at the playback time.