Zaf-Matlab

Zafar's Audio Functions in Matlab for audio signal analysis

Zafar's Audio Functions in Matlab for audio signal analysis.

Files:

- zaf.m: Matlab class with the audio functions.

- examples.ipynb: Jupyter notebook with some examples.

- audio_file.wav: audio file used for the examples.

Functions:

- stft - Compute the short-time Fourier transform (STFT).

- istft - Compute the inverse STFT.

- melfilterbank - Compute the mel filterbank.

- melspectrogram - Compute the mel spectrogram using a mel filterbank.

- mfcc - Compute the mel-frequency cepstral coefficients (MFCCs) using a mel filterbank.

- cqtkernel - Compute the constant-Q transform (CQT) kernel.

- cqtspectrogram - Compute the CQT spectrogram using a CQT kernel.

- cqtchromagram - Compute the CQT chromagram using a CQT kernel.

- dct - Compute the discrete cosine transform (DCT) using the fast Fourier transform (FFT).

- dst - Compute the discrete sine transform (DST) using the FFT.

- mdct - Compute the modified discrete cosine transform (MDCT) using the FFT.

- imdct - Compute the inverse MDCT using the FFT.

stft

audio_stft = zaf.stft(audio_signal,window_function,step_length);

- audio_signal: audio signal [number_samples,1]

- window_function: window function [window_length,1]

- step_length: step length in samples

- audio_stft: audio STFT [window_length,number_frames]

istft

audio_signal = zaf.istft(audio_stft,window_function,step_length);

- audio_stft: audio STFT [window_length,number_frames]

- window_function: window function [window_length,1]

- step_length: step length in samples

- audio_signal: audio signal [number_samples,1]

melfilterbank

mel_filterbank = zaf.melfilterbank(audio_signal,sampling_frequency,number_filters,number_coefficients);

- sampling_frequency: sampling frequency in Hz

- window_length: window length for the Fourier analysis in samples

- number_mels: number of mel filters

- mel_filterbank: mel filterbank (sparse) [number_mels,number_frequencies]

melspectrogram

mel_spectrogram = zaf.melspectrogram(audio_signal, window_function, step_length, mel_filterbank);

- audio_signal: audio signal [number_samples,1]

- window_function: window function [window_length,1]

- step_length: step length in samples

- mel_filterbank: mel filterbank [number_mels,number_frequencies]

- mel_spectrogram: mel spectrogram [number_mels,number_times]

mfcc

audio_mfcc = zaf.mfcc(audio_signal,sampling_frequency,number_filters,number_coefficients);

- audio_signal: audio signal [number_samples,1]

- window_function: window function [window_length,1]

- step_length: step length in samples

- mel_filterbank: mel filterbank [number_mels,number_frequencies]

- number_coefficients: number of coefficients (without the 0th coefficient)

- audio_mfcc: audio MFCCs [number_coefficients, number_times]

cqtkernel

cqt_kernel = zaf.cqtkernel(sampling_frequency,octave_resolution,minimum_frequency,maximum_frequency);

- sampling_frequency: sampling frequency in Hz

- octave_resolution: number of frequency channels per octave

- minimum_frequency: minimum frequency in Hz

- maximum_frequency: maximum frequency in Hz

- cqt_kernel: CQT kernel (sparse) [number_frequencies,fft_length]

cqtspectrogram

cqt_spectrogram = zaf.cqtspectrogram(audio_signal,sampling_frequency,time_resolution,cqt_kernel);

- audio_signal: audio signal [number_samples,1]

- sampling_frequency: sampling frequency in Hz

- time_resolution: time resolution in number of time frames per second

- cqt_kernel: CQT kernel [number_frequencies,fft_length]

- cqt_spectrogram: CQT spectrogram [number_frequencies,number_times]

cqtchromagram

cqt_chromagram = zaf.cqtchromagram(audio_signal,sampling_frequency,time_resolution,octave_resolution,cqt_kernel);

- audio_signal: audio signal [number_samples,1]

- sampling_frequency: sample frequency in Hz

- time_resolution: number of time frames per second

- octave_resolution: number of frequency channels per octave

- cqt_kernel: CQT kernel [number_frequencies,fft_length]

- cqt_chromagram: CQT chromagram [number_chromas,number_times]

dct

audio_dct = zaf.dct(audio_signal,dct_type);

- audio_signal: audio signal [number_samples,1]

- dct_type: DCT type (1, 2, 3, or 4)

- audio_dct: audio DCT [number_frequencies,1]

dst

audio_dst = zaf.dst(audio_signal,dst_type);

- audio_signal: audio signal [number_samples,1]

- dst_type: DST type (1, 2, 3, or 4)

- audio_dst: audio DST [number_frequencies,1]

mdct

audio_mdct = zaf.mdct(audio_signal,window_function);

- audio_signal: audio signal [number_samples,1]

- window_function: window function [window_length,1]

- audio_mdct: audio MDCT [number_frequencies,number_times]

imdct

audio_signal = zaf.imdct(audio_mdct,window_function);

- audio_mdct: audio MDCT [number_frequencies,number_times]

- window_function: window function [window_length,1]

- audio_signal: audio signal [number_samples,1]

Author:

- Zafar Rafii

- [e-mail]

- http://zafarrafii.com

- https://github.com/zafarrafii

- https://www.linkedin.com/in/zafarrafii/

See also: https://github.com/zafarrafii/Zaf-Matlab