A typical codec extracts sinusoid information from the samples by applying a short fourier transform to the samples and using that to find the important harmonic content of a single frame. By matching sinusses across frames, the encoder is capable of grouping them into harmonic lines and individual sinusses. The longer a track the encoder can find, the better it will be able to reduce the final bitrate. Synthesizing only the sinusoids sounds artificial and metallic. To mask this, the encoder subtracts the synthesized sinusses from the original audio signal. The residual is then matched to a linear filter that is excited with white noise. The extracted parameters can than be quantized, coded and multiplexed into a bitstream.