Both Librosa and Scipy have the fft function, however, they give me a different spectrogram output even with the same signal input. Then I get the following spectrogram. The two spectrogram are obviously different, specifically, the Librosa version has an attack at the very beginning.
What causes the difference? I don't see many parameters that I can tune in the documentation for Scipy and Librosa. The reason for this is the argument center for librosa's stft. By default, STFT uses reflection padding. Note that librosa's stft also uses the Hann window function by default. If you want to avoid this and make it more like your Scipy stft implementation, call the stft with a window consisting only of ones:. Learn more.
Librosa's fft and Scipy's fft are different? Ask Question. Asked 1 year, 1 month ago. Active 1 year, 1 month ago. Viewed 2k times. Scipy I am trying to get the spectrogram with the following code import numpy as np fast vectors and matrices import matplotlib. Hendrik 3, 15 15 silver badges 32 32 bronze badges.
Raven Cheuk Raven Cheuk 1, 2 2 gold badges 12 12 silver badges 29 29 bronze badges. There's a difference, as the STFT often includes windowing and padding. See my answer below. Active Oldest Votes. From the docs: librosa. Hendrik Hendrik 3, 15 15 silver badges 32 32 bronze badges. Sign up or log in Sign up using Google.
Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Tales from documentation: Write for your clueless users. Podcast a conversation on diversity and representation. Upcoming Events. Featured on Meta. Feedback post: New moderator reinstatement and appeal process revisions.
Therefore, if i take stft[number of fBin] which is 1 row of fBins stft and look at it contents so stft contains points, which are exactly time points for each frequency so each of the frames will have the same time points. Otherwise the default value 22, Hz will be used see docs. Instead, it takes number of frames as first argument. Then you get one frame per hop and the hop is 0. This means the first dimension is the frequency bin and the second dimension is the frame number t.
The total number of frames in stft is therefore stft. To get the length of the source audio, you could do:. Learn more. Asked 12 months ago. Active 12 months ago. Viewed times. Amit Neuhaus. Amit Neuhaus Amit Neuhaus 8 8 bronze badges. Have you tried specifying sr as parameter to specshow? Active Oldest Votes.
Question 1: You need to specify the sampling rate when using specshow : librosa. Question 2: librosa. Hendrik Hendrik 3, 15 15 silver badges 32 32 bronze badges. Can you please Asnwer the second question aswell? Cant close because 2nd Questions sitll havent answered. Thanks again. How about now? All questions answered? Sign up or log in Sign up using Google.
Sign up using Facebook. Sign up using Email and Password.
Subscribe to RSS
Post as a guest Name. Email Required, but never shown. The Overflow Blog. Tales from documentation: Write for your clueless users.
Podcast a conversation on diversity and representation. Upcoming Events. Featured on Meta. Feedback post: New moderator reinstatement and appeal process revisions. The new moderator agreement is now live for moderators to accept across the….GitHub is home to over 50 million developers working together to host and review code, manage projects, and build software together. Have a question about this project?
Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Already on GitHub? Sign in to your account. Option 2 is the easiest to implement. However, it's also a little cumbersome, since we would have two bits to convey a 3-way choice. This is probably okay, but feels clumsy. Option 3 would take some more work, but might be the best in the long run, since it forces the user to be totally explicit. It also would gracefully extend to more options in the future, if we decide they're necessary.
What do you think dpwe? No strong opinions have been expressed, so I'll exercise dictatorial power to choose option 3, but punt it from the 0.
Skip to content.
Dismiss Join GitHub today GitHub is home to over 50 million developers working together to host and review code, manage projects, and build software together. Sign up. New issue. Jump to bottom. Labels API change Hacktoberfest enhancement. Copy link Quote reply. Questions: Should this be controlled by a separate flag? Member Author. Here are the three options on the table: Change the padding behavior to always be window-centered rather than frame-centered. This breaks backward compatibility.
If left to frame by default, this preserves backward compatibility. Change the padding control to have three modes, as described above. Replace boolean flags with an enum. I'm against option 1, since it doesn't provide a graceful way to recover the current behavior.
Some question when extracting MFCC features Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment. API change Hacktoberfest enhancement. Linked pull requests.The following are code examples for showing how to use librosa.
They are from open source Python projects. You can vote up the examples you like or vote down the ones you don't like. ArgumentParser numpy. More from librosa. Python librosa. Args: x np. Returns: np. T Apply log nonlinearity and return as float32 return librosa.
Function 'stft2power' needs a non-empty matrix. Function 'stft2power' needs an existing matrix. Parameters wav : np. T return mag, phase. Returns a generator that outputs the approximated signal at the various iterations. T else: return librosa. FloatTensor spect if self. T else: return librosa. The dynamic spectrogram is obtained by computing the the signal in the frequency domain and display the spectrogram.
Args: data array : 1D array of audio data. The full path of a sound file. Args: fpath: A string. Parameters mag : np. Returns wav : np. Input can be a filepath to an audio file or a numpy array directly. By default, the whole audio is used for conversion. By setting duration to the desired number of seconds to be read from the audio file, reading can be sped up.
For accelerating reading, the buffer option can be activated so that a numpy filedump of the magnitudes and phases is created after processing and loaded the next time it is requested. Loading audio again and recreating npy file! The static spectromgram is computed by take the power of the signal in the frequency domain according a decomposition in mel bands and a maximum frequency.The reassignment vectors are calculated using equations 5. See  for additional algorithms, and  and  for history and discussion of the method.
Window length. See stft for details.
Minimum power threshold for estimating time-frequency reassignments. Any bin with np. If 0 is provided, then only bins with zero power will be returned as np. By default, STFT uses reflection padding. Instantaneous frequencies: freqs[f, t] is the frequency for bin fframe t.
Reassigned times: times[f, t] is the time for bin fframe t. Magnitudes from short-time Fourier transform: mags[f, t] is the magnitude for bin fframe t. Frequency or time estimates with zero support will produce a divide-by-zero warning, and will be returned as np. Unlike stftreassigned times are not aligned to the left or center of each frame, so padding the signal does not affect the meaning of the reassigned times. However, reassignment assumes that the energy in each FFT bin is associated with exactly one signal component and impulse event.
See also stft Short-time Fourier Transform. Other Versions v: 0. Flandrin, P. Time-Frequency reassignment: From principles to algorithms. CRC Press. Fulop, S. Algorithms for computing the time-corrected instantaneous frequency reassigned spectrogram, with applications. The Journal of the Acoustical Society of America, 1GitHub is home to over 50 million developers working together to host and review code, manage projects, and build software together.
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Already on GitHub? Sign in to your account. Fixes Users desiring fancy padding should pad explicitly before calling stft. Reviewed 3 of 3 files at r1. Review status: all files reviewed at latest revision, all discussions resolved. Comments from Reviewable. Skip to content.
Dismiss Join GitHub today GitHub is home to over 50 million developers working together to host and review code, manage projects, and build software together.
Sign up. New issue.
Source code for librosa.core.spectrum
Conversation 2 Commits 6 Checks 0 Files changed. Copy link Quote reply. Explain your changes. When STFT is center-aligned, we previously padded by reflection. This PR allows the user to change the padding mode to anything supported by np. Any other comments? No additional action is necessary in istft. I think this one's good to go as well; eyeballs would be nice but not necessary. Hide details View details bmcfee merged commit 8e7faec into master Apr 26, 5 checks passed.
Sign up for free to join this conversation on GitHub.Given a short-time Fourier transform magnitude matrix Sthe algorithm randomly initializes phase estimates, and then alternates forward- and inverse-STFT operations.
Note that this assumes reconstruction of a real-valued time-domain signal, and that S contains only the non-negative frequencies as computed by core.
An array of short-time Fourier transform magnitudes as produced by core. The hop length of the STFT.
The window length of the STFT. A window specification as supported by stft or istft. If provided, the output y is zero-padded or clipped to exactly length samples. By default, STFT uses reflection padding. The momentum parameter for fast Griffin-Lim. Setting this to 0 recovers the original Griffin-Lim method . Values near 1 can lead to faster convergence, but above 1 may not converge. This is recommended when the input S is a magnitude spectrogram with no initial phase estimates.
If Nonethen the phase is initialized from S. This is useful when an initial guess for phase can be provided, or when you want to resume Griffin-Lim from a previous output.
If np. RandomState instance, the random number generator itself. If Nonedefaults to the current np. Griffin and J. ASSP, vol. Parameters: S : np. Default is bit float. Returns: y : np. Other Versions v: 0.