👉 Mel's Mel-frequency cepstral coefficients (Mel-frequency cepstral coefficients, or Mel-frequency cepstral coefficients, or MTCs for short) are a method used in speech processing to analyze the spectral envelope of sounds, particularly in phonetics and speech recognition. The process starts by converting the raw audio signal into the mel-frequency domain using the mel-scale, which is a perceptual scale that approximates how humans perceive sound frequencies. This transformation helps in capturing the pitch variations more accurately than linear frequency scales. Next, a short-time Fourier transform (STFT) is applied to the mel-scaled audio to obtain the frequency spectrum over time. The log-mel transform is then computed from this spectrum, and the inverse discrete cosine transform (IDCT) is applied to convert it back into the time domain. The final step involves taking the discrete cosine transform (DCT) of the IDCT coefficients to produce the Mel-frequency cepstral coefficients. These coefficients represent the spectral envelope of the speech signal in a compact and perceptually meaningful way, making them useful for tasks like speech recognition, speaker identification, and quality control in audio systems.
