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Source code for librosa.display
#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Display
=======
Data visualization
------------------
.. autosummary::
:toctree: generated/
specshow
waveshow
Axis formatting
---------------
.. autosummary::
:toctree: generated/
TimeFormatter
NoteFormatter
SvaraFormatter
LogHzFormatter
ChromaFormatter
ChromaSvaraFormatter
TonnetzFormatter
Miscellaneous
-------------
.. autosummary::
:toctree: generated/
cmap
AdaptiveWaveplot
Deprecated
----------
.. autosummary::
:toctree: generated/
waveplot
"""
import warnings
import numpy as np
from matplotlib.cm import get_cmap
from matplotlib.axes import Axes
from matplotlib.ticker import Formatter, ScalarFormatter
from matplotlib.ticker import LogLocator, FixedLocator, MaxNLocator
from matplotlib.ticker import SymmetricalLogLocator
import matplotlib
from packaging.version import parse as version_parse
from . import core
from . import util
from .util.exceptions import ParameterError
__all__ = [
"specshow",
"waveshow",
"waveplot",
"cmap",
"TimeFormatter",
"NoteFormatter",
"LogHzFormatter",
"ChromaFormatter",
"TonnetzFormatter",
"AdaptiveWaveplot",
]
[docs]class TimeFormatter(Formatter):
"""A tick formatter for time axes.
Automatically switches between seconds, minutes:seconds,
or hours:minutes:seconds.
Parameters
----------
lag : bool
If ``True``, then the time axis is interpreted in lag coordinates.
Anything past the midpoint will be converted to negative time.
unit : str or None
Abbreviation of the physical unit for axis labels and ticks.
Either equal to `s` (seconds) or `ms` (milliseconds) or None (default).
If set to None, the resulting TimeFormatter object adapts its string
representation to the duration of the underlying time range:
`hh:mm:ss` above 3600 seconds; `mm:ss` between 60 and 3600 seconds;
and `ss` below 60 seconds.
See also
--------
matplotlib.ticker.Formatter
Examples
--------
For normal time
>>> import matplotlib.pyplot as plt
>>> times = np.arange(30)
>>> values = np.random.randn(len(times))
>>> fig, ax = plt.subplots()
>>> ax.plot(times, values)
>>> ax.xaxis.set_major_formatter(librosa.display.TimeFormatter())
>>> ax.set(xlabel='Time')
Manually set the physical time unit of the x-axis to milliseconds
>>> times = np.arange(100)
>>> values = np.random.randn(len(times))
>>> fig, ax = plt.subplots()
>>> ax.plot(times, values)
>>> ax.xaxis.set_major_formatter(librosa.display.TimeFormatter(unit='ms'))
>>> ax.set(xlabel='Time (ms)')
For lag plots
>>> times = np.arange(60)
>>> values = np.random.randn(len(times))
>>> fig, ax = plt.subplots()
>>> ax.plot(times, values)
>>> ax.xaxis.set_major_formatter(librosa.display.TimeFormatter(lag=True))
>>> ax.set(xlabel='Lag')
"""
[docs] def __init__(self, lag=False, unit=None):
if unit not in ["s", "ms", None]:
raise ParameterError("Unknown time unit: {}".format(unit))
self.unit = unit
self.lag = lag
def __call__(self, x, pos=None):
"""Return the time format as pos"""
_, dmax = self.axis.get_data_interval()
vmin, vmax = self.axis.get_view_interval()
# In lag-time axes, anything greater than dmax / 2 is negative time
if self.lag and x >= dmax * 0.5:
# In lag mode, don't tick past the limits of the data
if x > dmax:
return ""
value = np.abs(x - dmax)
# Do we need to tweak vmin/vmax here?
sign = "-"
else:
value = x
sign = ""
if self.unit == "s":
s = "{:.3g}".format(value)
elif self.unit == "ms":
s = "{:.3g}".format(value * 1000)
else:
if vmax - vmin > 3600:
# Hours viz
s = "{:d}:{:02d}:{:02d}".format(
int(value / 3600.0),
int(np.mod(value / 60.0, 60)),
int(np.mod(value, 60)),
)
elif vmax - vmin > 60:
# Minutes viz
s = "{:d}:{:02d}".format(int(value / 60.0), int(np.mod(value, 60)))
elif vmax - vmin >= 1:
# Seconds viz
s = "{:.2g}".format(value)
else:
# Milliseconds viz
s = "{:.3f}".format(value)
return "{:s}{:s}".format(sign, s)
[docs]class NoteFormatter(Formatter):
"""Ticker formatter for Notes
Parameters
----------
octave : bool
If ``True``, display the octave number along with the note name.
Otherwise, only show the note name (and cent deviation)
major : bool
If ``True``, ticks are always labeled.
If ``False``, ticks are only labeled if the span is less than 2 octaves
See also
--------
LogHzFormatter
matplotlib.ticker.Formatter
Examples
--------
>>> import matplotlib.pyplot as plt
>>> values = librosa.midi_to_hz(np.arange(48, 72))
>>> fig, ax = plt.subplots(nrows=2)
>>> ax[0].bar(np.arange(len(values)), values)
>>> ax[0].set(ylabel='Hz')
>>> ax[1].bar(np.arange(len(values)), values)
>>> ax[1].yaxis.set_major_formatter(librosa.display.NoteFormatter())
>>> ax[1].set(ylabel='Note')
"""
[docs] def __init__(self, octave=True, major=True, key="C:maj"):
self.octave = octave
self.major = major
self.key = key
def __call__(self, x, pos=None):
if x <= 0:
return ""
# Only use cent precision if our vspan is less than an octave
vmin, vmax = self.axis.get_view_interval()
if not self.major and vmax > 4 * max(1, vmin):
return ""
cents = vmax <= 2 * max(1, vmin)
return core.hz_to_note(x, octave=self.octave, cents=cents, key=self.key)
[docs]class SvaraFormatter(Formatter):
"""Ticker formatter for Svara
Parameters
----------
octave : bool
If ``True``, display the octave number along with the note name.
Otherwise, only show the note name (and cent deviation)
major : bool
If ``True``, ticks are always labeled.
If ``False``, ticks are only labeled if the span is less than 2 octaves
Sa : number > 0
Frequency (in Hz) of Sa
mela : str or int
For Carnatic svara, the index or name of the melakarta raga in question
To use Hindustani svara, set ``mela=None``
See also
--------
NoteFormatter
matplotlib.ticker.Formatter
librosa.hz_to_svara_c
librosa.hz_to_svara_h
Examples
--------
>>> import matplotlib.pyplot as plt
>>> values = librosa.midi_to_hz(np.arange(48, 72))
>>> fig, ax = plt.subplots(nrows=2)
>>> ax[0].bar(np.arange(len(values)), values)
>>> ax[0].set(ylabel='Hz')
>>> ax[1].bar(np.arange(len(values)), values)
>>> ax[1].yaxis.set_major_formatter(librosa.display.SvaraFormatter(261))
>>> ax[1].set(ylabel='Note')
"""
[docs] def __init__(self, Sa, octave=True, major=True, abbr=False, mela=None):
if Sa is None:
raise ParameterError(
"Sa frequency is required for svara display formatting"
)
self.Sa = Sa
self.octave = octave
self.major = major
self.abbr = abbr
self.mela = mela
def __call__(self, x, pos=None):
if x <= 0:
return ""
# Only use cent precision if our vspan is less than an octave
vmin, vmax = self.axis.get_view_interval()
if not self.major and vmax > 4 * max(1, vmin):
return ""
if self.mela is None:
return core.hz_to_svara_h(x, self.Sa, octave=self.octave, abbr=self.abbr)
else:
return core.hz_to_svara_c(
x, self.Sa, self.mela, octave=self.octave, abbr=self.abbr
)
[docs]class LogHzFormatter(Formatter):
"""Ticker formatter for logarithmic frequency
Parameters
----------
major : bool
If ``True``, ticks are always labeled.
If ``False``, ticks are only labeled if the span is less than 2 octaves
See also
--------
NoteFormatter
matplotlib.ticker.Formatter
Examples
--------
>>> import matplotlib.pyplot as plt
>>> values = librosa.midi_to_hz(np.arange(48, 72))
>>> fig, ax = plt.subplots(nrows=2)
>>> ax[0].bar(np.arange(len(values)), values)
>>> ax[0].yaxis.set_major_formatter(librosa.display.LogHzFormatter())
>>> ax[0].set(ylabel='Hz')
>>> ax[1].bar(np.arange(len(values)), values)
>>> ax[1].yaxis.set_major_formatter(librosa.display.NoteFormatter())
>>> ax[1].set(ylabel='Note')
"""
def __call__(self, x, pos=None):
if x <= 0:
return ""
vmin, vmax = self.axis.get_view_interval()
if not self.major and vmax > 4 * max(1, vmin):
return ""
return "{:g}".format(x)
[docs]class ChromaFormatter(Formatter):
"""A formatter for chroma axes
See also
--------
matplotlib.ticker.Formatter
Examples
--------
>>> import matplotlib.pyplot as plt
>>> values = np.arange(12)
>>> fig, ax = plt.subplots()
>>> ax.plot(values)
>>> ax.yaxis.set_major_formatter(librosa.display.ChromaFormatter())
>>> ax.set(ylabel='Pitch class')
"""
def __call__(self, x, pos=None):
"""Format for chroma positions"""
return core.midi_to_note(int(x), octave=False, cents=False, key=self.key)
[docs]class ChromaSvaraFormatter(Formatter):
"""A formatter for chroma axes with svara instead of notes.
If mela is given, Carnatic svara names will be used.
Otherwise, Hindustani svara names will be used.
If `Sa` is not given, it will default to 0 (equivalent to `C`).
See Also
--------
ChromaFormatter
"""
[docs] def __init__(self, Sa=None, mela=None, abbr=True):
if Sa is None:
Sa = 0
self.Sa = Sa
self.mela = mela
self.abbr = abbr
def __call__(self, x, pos=None):
"""Format for chroma positions"""
if self.mela is not None:
return core.midi_to_svara_c(
int(x), Sa=self.Sa, mela=self.mela, octave=False, abbr=self.abbr
)
else:
return core.midi_to_svara_h(
int(x), Sa=self.Sa, octave=False, abbr=self.abbr
)
[docs]class TonnetzFormatter(Formatter):
"""A formatter for tonnetz axes
See also
--------
matplotlib.ticker.Formatter
Examples
--------
>>> import matplotlib.pyplot as plt
>>> values = np.arange(6)
>>> fig, ax = plt.subplots()
>>> ax.plot(values)
>>> ax.yaxis.set_major_formatter(librosa.display.TonnetzFormatter())
>>> ax.set(ylabel='Tonnetz')
"""
def __call__(self, x, pos=None):
"""Format for tonnetz positions"""
return [r"5$_x$", r"5$_y$", r"m3$_x$", r"m3$_y$", r"M3$_x$", r"M3$_y$"][int(x)]
[docs]class AdaptiveWaveplot:
"""A helper class for managing adaptive wave visualizations.
This object is used to dynamically switch between sample-based and envelope-based
visualizations of waveforms.
When the display is zoomed in such that no more than `max_samples` would be
visible, the sample-based display is used.
When displaying the raw samples would require more than `max_samples`, an
envelope-based plot is used instead.
You should never need to instantiate this object directly, as it is constructed
automatically by `waveshow`.
Parameters
----------
times : np.ndarray
An array containing the time index (in seconds) for each sample.
y : np.ndarray
An array containing the (monophonic) wave samples.
steps : matplotlib.lines.Lines2D
The matplotlib artist used for the sample-based visualization.
This is constructed by `matplotlib.pyplot.step`.
envelope : matplotlib.collections.PolyCollection
The matplotlib artist used for the envelope-based visualization.
This is constructed by `matplotlib.pyplot.fill_between`.
sr : number > 0
The sampling rate of the audio
max_samples : int > 0
The maximum number of samples to use for sample-based display.
See Also
--------
waveshow
"""
[docs] def __init__(self, times, y, steps, envelope, sr=22050, max_samples=11025):
self.times = times
self.samples = y
self.steps = steps
self.envelope = envelope
self.sr = sr
self.max_samples = max_samples
def update(self, ax):
"""Update the matplotlib display according to the current viewport limits.
This is a callback function, and should not be used directly.
Parameters
----------
ax : matplotlib axes object
The axes object to update
"""
lims = ax.viewLim
# Does our width cover fewer than max_samples?
# If so, then use the sample-based plot
if lims.width * self.sr <= self.max_samples:
self.envelope.set_visible(False)
self.steps.set_visible(True)
# Now check that our viewport
xdata = self.steps.get_xdata()
if lims.x0 <= xdata[0] or lims.x1 >= xdata[-1]:
# Viewport expands beyond current data in steps; update
# we want to cover a window of self.max_samples centered on the current viewport
midpoint_time = (lims.x1 + lims.x0) / 2
idx_start = np.searchsorted(
self.times, midpoint_time - 0.5 * self.max_samples / self.sr
)
self.steps.set_data(
self.times[idx_start : idx_start + self.max_samples],
self.samples[idx_start : idx_start + self.max_samples],
)
else:
# Otherwise, use the envelope plot
self.envelope.set_visible(True)
self.steps.set_visible(False)
ax.figure.canvas.draw_idle()
[docs]def cmap(data, robust=True, cmap_seq="magma", cmap_bool="gray_r", cmap_div="coolwarm"):
"""Get a default colormap from the given data.
If the data is boolean, use a black and white colormap.
If the data has both positive and negative values,
use a diverging colormap.
Otherwise, use a sequential colormap.
Parameters
----------
data : np.ndarray
Input data
robust : bool
If True, discard the top and bottom 2% of data when calculating
range.
cmap_seq : str
The sequential colormap name
cmap_bool : str
The boolean colormap name
cmap_div : str
The diverging colormap name
Returns
-------
cmap : matplotlib.colors.Colormap
The colormap to use for ``data``
See Also
--------
matplotlib.pyplot.colormaps
"""
data = np.atleast_1d(data)
if data.dtype == "bool":
return get_cmap(cmap_bool, lut=2)
data = data[np.isfinite(data)]
if robust:
min_p, max_p = 2, 98
else:
min_p, max_p = 0, 100
min_val, max_val = np.percentile(data, [min_p, max_p])
if min_val >= 0 or max_val <= 0:
return get_cmap(cmap_seq)
return get_cmap(cmap_div)
def __envelope(x, hop):
"""Compute the max-envelope of non-overlapping frames of x at length hop
x is assumed to be multi-channel, of shape (n_channels, n_samples).
"""
x_frame = np.abs(util.frame(x, frame_length=hop, hop_length=hop))
return x_frame.max(axis=1)
[docs]@util.decorators.deprecated("0.8.1", "0.9.0")
def waveplot(
y,
sr=22050,
max_points=5e4,
x_axis="time",
offset=0.0,
max_sr=1000,
ax=None,
**kwargs,
):
"""Plot the amplitude envelope of a waveform.
If ``y`` is monophonic, a filled curve is drawn between ``[-abs(y), abs(y)]``.
If ``y`` is stereo, the curve is drawn between ``[-abs(y[1]), abs(y[0])]``,
so that the left and right channels are drawn above and below the axis,
respectively.
Long signals (``duration >= max_points``) are down-sampled to at
most ``max_sr`` before plotting.
.. warning::
This function is deprecated in librosa 0.8.1 and will be removed
in 0.9.0. Its functionality is replaced and extended by `waveshow`.
Parameters
----------
y : np.ndarray [shape=(n,) or (2,n)]
audio time series (mono or stereo)
sr : number > 0 [scalar]
sampling rate of ``y``
max_points : postive number or None
Maximum number of time-points to plot: if ``max_points`` exceeds
the duration of ``y``, then ``y`` is downsampled.
If `None`, no downsampling is performed.
x_axis : str or None
Display of the x-axis ticks and tick markers. Accepted values are:
- 'time' : markers are shown as milliseconds, seconds, minutes, or hours.
Values are plotted in units of seconds.
- 's' : markers are shown as seconds.
- 'ms' : markers are shown as milliseconds.
- 'lag' : like time, but past the halfway point counts as negative values.
- 'lag_s' : same as lag, but in seconds.
- 'lag_ms' : same as lag, but in milliseconds.
- `None`, 'none', or 'off': ticks and tick markers are hidden.
ax : matplotlib.axes.Axes or None
Axes to plot on instead of the default `plt.gca()`.
offset : float
Horizontal offset (in seconds) to start the waveform plot
max_sr : number > 0 [scalar]
Maximum sampling rate for the visualization
kwargs
Additional keyword arguments to `matplotlib.pyplot.fill_between`
Returns
-------
pc : matplotlib.collections.PolyCollection
The PolyCollection created by `fill_between`.
See also
--------
waveshow
librosa.resample
matplotlib.pyplot.fill_between
Examples
--------
Plot a monophonic waveform
>>> import matplotlib.pyplot as plt
>>> y, sr = librosa.load(librosa.ex('choice'), duration=10)
>>> fig, ax = plt.subplots(nrows=3, sharex=True, sharey=True)
>>> librosa.display.waveplot(y, sr=sr, ax=ax[0])
>>> ax[0].set(title='Monophonic')
>>> ax[0].label_outer()
Or a stereo waveform
>>> y, sr = librosa.load(librosa.ex('choice', hq=True), mono=False, duration=10)
>>> librosa.display.waveplot(y, sr=sr, ax=ax[1])
>>> ax[1].set(title='Stereo')
>>> ax[1].label_outer()
Or harmonic and percussive components with transparency
>>> y, sr = librosa.load(librosa.ex('choice'), duration=10)
>>> y_harm, y_perc = librosa.effects.hpss(y)
>>> librosa.display.waveplot(y_harm, sr=sr, alpha=0.25, ax=ax[2])
>>> librosa.display.waveplot(y_perc, sr=sr, color='r', alpha=0.5, ax=ax[2])
>>> ax[2].set(title='Harmonic + Percussive')
"""
util.valid_audio(y, mono=False)
if not (isinstance(max_sr, (int, np.integer)) and max_sr > 0):
raise ParameterError("max_sr must be a non-negative integer")
target_sr = sr
hop_length = 1
# Pad an extra channel dimension, if necessary
if y.ndim == 1:
y = y[np.newaxis, :]
if max_points is not None:
if max_points <= 0:
raise ParameterError("max_points must be strictly positive")
if max_points < y.shape[-1]:
target_sr = min(max_sr, (sr * y.shape[-1]) // max_points)
hop_length = sr // target_sr
# Reduce by envelope calculation
y = __envelope(y, hop_length)
y_top = y[0]
y_bottom = -y[-1]
axes = __check_axes(ax)
kwargs.setdefault("color", next(axes._get_lines.prop_cycler)["color"])
locs = offset + core.times_like(y_top, sr=sr, hop_length=hop_length)
out = axes.fill_between(locs, y_bottom, y_top, **kwargs)
axes.set_xlim([locs.min(), locs.max()])
# Construct tickers and locators
__decorate_axis(axes.xaxis, x_axis)
return out
[docs]def specshow(
data,
x_coords=None,
y_coords=None,
x_axis=None,
y_axis=None,
sr=22050,
hop_length=512,
fmin=None,
fmax=None,
tuning=0.0,
bins_per_octave=12,
key="C:maj",
Sa=None,
mela=None,
thaat=None,
auto_aspect=True,
htk=False,
ax=None,
**kwargs,
):
"""Display a spectrogram/chromagram/cqt/etc.
For a detailed overview of this function, see :ref:`sphx_glr_auto_examples_plot_display.py`
Parameters
----------
data : np.ndarray [shape=(d, n)]
Matrix to display (e.g., spectrogram)
sr : number > 0 [scalar]
Sample rate used to determine time scale in x-axis.
hop_length : int > 0 [scalar]
Hop length, also used to determine time scale in x-axis
x_axis, y_axis : None or str
Range for the x- and y-axes.
Valid types are:
- None, 'none', or 'off' : no axis decoration is displayed.
Frequency types:
- 'linear', 'fft', 'hz' : frequency range is determined by
the FFT window and sampling rate.
- 'log' : the spectrum is displayed on a log scale.
- 'fft_note': the spectrum is displayed on a log scale with pitches marked.
- 'fft_svara': the spectrum is displayed on a log scale with svara marked.
- 'mel' : frequencies are determined by the mel scale.
- 'cqt_hz' : frequencies are determined by the CQT scale.
- 'cqt_note' : pitches are determined by the CQT scale.
- 'cqt_svara' : like `cqt_note` but using Hindustani or Carnatic svara
All frequency types are plotted in units of Hz.
Any spectrogram parameters (hop_length, sr, bins_per_octave, etc.)
used to generate the input data should also be provided when
calling `specshow`.
Categorical types:
- 'chroma' : pitches are determined by the chroma filters.
Pitch classes are arranged at integer locations (0-11) according to
a given key.
- `chroma_h`, `chroma_c`: pitches are determined by chroma filters,
and labeled as svara in the Hindustani (`chroma_h`) or Carnatic (`chroma_c`)
according to a given thaat (Hindustani) or melakarta raga (Carnatic).
- 'tonnetz' : axes are labeled by Tonnetz dimensions (0-5)
- 'frames' : markers are shown as frame counts.
Time types:
- 'time' : markers are shown as milliseconds, seconds, minutes, or hours.
Values are plotted in units of seconds.
- 's' : markers are shown as seconds.
- 'ms' : markers are shown as milliseconds.
- 'lag' : like time, but past the halfway point counts as negative values.
- 'lag_s' : same as lag, but in seconds.
- 'lag_ms' : same as lag, but in milliseconds.
Rhythm:
- 'tempo' : markers are shown as beats-per-minute (BPM)
using a logarithmic scale. This is useful for
visualizing the outputs of `feature.tempogram`.
- 'fourier_tempo' : same as `'tempo'`, but used when
tempograms are calculated in the Frequency domain
using `feature.fourier_tempogram`.
x_coords, y_coords : np.ndarray [shape=data.shape[0 or 1]+1]
Optional positioning coordinates of the input data.
These can be use to explicitly set the location of each
element ``data[i, j]``, e.g., for displaying beat-synchronous
features in natural time coordinates.
If not provided, they are inferred from ``x_axis`` and ``y_axis``.
fmin : float > 0 [scalar] or None
Frequency of the lowest spectrogram bin. Used for Mel and CQT
scales.
If ``y_axis`` is `cqt_hz` or `cqt_note` and ``fmin`` is not given,
it is set by default to ``note_to_hz('C1')``.
fmax : float > 0 [scalar] or None
Used for setting the Mel frequency scales
tuning : float
Tuning deviation from A440, in fractions of a bin.
This is used for CQT frequency scales, so that ``fmin`` is adjusted
to ``fmin * 2**(tuning / bins_per_octave)``.
bins_per_octave : int > 0 [scalar]
Number of bins per octave. Used for CQT frequency scale.
key : str
The reference key to use when using note axes (`cqt_note`, `chroma`).
Sa : float or int
If using Hindustani or Carnatic svara axis decorations, specify Sa.
For `cqt_svara`, ``Sa`` should be specified as a frequency in Hz.
For `chroma_c` or `chroma_h`, ``Sa`` should correspond to the position
of Sa within the chromagram.
If not provided, Sa will default to 0 (equivalent to `C`)
mela : str or int, optional
If using `chroma_c` or `cqt_svara` display mode, specify the melakarta raga.
thaat : str, optional
If using `chroma_h` display mode, specify the parent thaat.
auto_aspect : bool
Axes will have 'equal' aspect if the horizontal and vertical dimensions
cover the same extent and their types match.
To override, set to `False`.
htk : bool
If plotting on a mel frequency axis, specify which version of the mel
scale to use.
- `False`: use Slaney formula (default)
- `True`: use HTK formula
See `core.mel_frequencies` for more information.
ax : matplotlib.axes.Axes or None
Axes to plot on instead of the default `plt.gca()`.
kwargs : additional keyword arguments
Arguments passed through to `matplotlib.pyplot.pcolormesh`.
By default, the following options are set:
- ``rasterized=True``
- ``shading='flat'``
- ``edgecolors='None'``
Returns
-------
colormesh : `matplotlib.collections.QuadMesh`
The color mesh object produced by `matplotlib.pyplot.pcolormesh`
See Also
--------
cmap : Automatic colormap detection
matplotlib.pyplot.pcolormesh
Examples
--------
Visualize an STFT power spectrum using default parameters
>>> import matplotlib.pyplot as plt
>>> y, sr = librosa.load(librosa.ex('choice'), duration=15)
>>> fig, ax = plt.subplots(nrows=2, ncols=1, sharex=True)
>>> D = librosa.amplitude_to_db(np.abs(librosa.stft(y)), ref=np.max)
>>> img = librosa.display.specshow(D, y_axis='linear', x_axis='time',
... sr=sr, ax=ax[0])
>>> ax[0].set(title='Linear-frequency power spectrogram')
>>> ax[0].label_outer()
Or on a logarithmic scale, and using a larger hop
>>> hop_length = 1024
>>> D = librosa.amplitude_to_db(np.abs(librosa.stft(y, hop_length=hop_length)),
... ref=np.max)
>>> librosa.display.specshow(D, y_axis='log', sr=sr, hop_length=hop_length,
... x_axis='time', ax=ax[1])
>>> ax[1].set(title='Log-frequency power spectrogram')
>>> ax[1].label_outer()
>>> fig.colorbar(img, ax=ax, format="%+2.f dB")
"""
if np.issubdtype(data.dtype, np.complexfloating):
warnings.warn(
"Trying to display complex-valued input. " "Showing magnitude instead."
)
data = np.abs(data)
kwargs.setdefault("cmap", cmap(data))
kwargs.setdefault("rasterized", True)
kwargs.setdefault("edgecolors", "None")
kwargs.setdefault("shading", "flat")
all_params = dict(
kwargs=kwargs,
sr=sr,
fmin=fmin,
fmax=fmax,
tuning=tuning,
bins_per_octave=bins_per_octave,
hop_length=hop_length,
key=key,
htk=htk,
)
# Get the x and y coordinates
y_coords = __mesh_coords(y_axis, y_coords, data.shape[0], **all_params)
x_coords = __mesh_coords(x_axis, x_coords, data.shape[1], **all_params)
axes = __check_axes(ax)
out = axes.pcolormesh(x_coords, y_coords, data, **kwargs)
__set_current_image(ax, out)
axes.set_xlim(x_coords.min(), x_coords.max())
axes.set_ylim(y_coords.min(), y_coords.max())
# Set up axis scaling
__scale_axes(axes, x_axis, "x")
__scale_axes(axes, y_axis, "y")
# Construct tickers and locators
__decorate_axis(axes.xaxis, x_axis, key=key, Sa=Sa, mela=mela, thaat=thaat)
__decorate_axis(axes.yaxis, y_axis, key=key, Sa=Sa, mela=mela, thaat=thaat)
# If the plot is a self-similarity/covariance etc. plot, square it
if __same_axes(x_axis, y_axis, axes.get_xlim(), axes.get_ylim()) and auto_aspect:
axes.set_aspect("equal")
return out
def __set_current_image(ax, img):
"""Helper to set the current image in pyplot mode.
If the provided ``ax`` is not `None`, then we assume that the user is using the object API.
In this case, the pyplot current image is not set.
"""
if ax is None:
import matplotlib.pyplot as plt
plt.sci(img)
def __mesh_coords(ax_type, coords, n, **kwargs):
"""Compute axis coordinates"""
if coords is not None:
if len(coords) < n:
raise ParameterError(
"Coordinate shape mismatch: " "{}<{}".format(len(coords), n)
)
return coords
coord_map = {
"linear": __coord_fft_hz,
"fft": __coord_fft_hz,
"fft_note": __coord_fft_hz,
"fft_svara": __coord_fft_hz,
"hz": __coord_fft_hz,
"log": __coord_fft_hz,
"mel": __coord_mel_hz,
"cqt": __coord_cqt_hz,
"cqt_hz": __coord_cqt_hz,
"cqt_note": __coord_cqt_hz,
"cqt_svara": __coord_cqt_hz,
"chroma": __coord_chroma,
"chroma_c": __coord_chroma,
"chroma_h": __coord_chroma,
"time": __coord_time,
"s": __coord_time,
"ms": __coord_time,
"lag": __coord_time,
"lag_s": __coord_time,
"lag_ms": __coord_time,
"tonnetz": __coord_n,
"off": __coord_n,
"tempo": __coord_tempo,
"fourier_tempo": __coord_fourier_tempo,
"frames": __coord_n,
None: __coord_n,
}
if ax_type not in coord_map:
raise ParameterError("Unknown axis type: {}".format(ax_type))
return coord_map[ax_type](n, **kwargs)
def __check_axes(axes):
"""Check if "axes" is an instance of an axis object. If not, use `gca`."""
if axes is None:
import matplotlib.pyplot as plt
axes = plt.gca()
elif not isinstance(axes, Axes):
raise ParameterError(
"`axes` must be an instance of matplotlib.axes.Axes. "
"Found type(axes)={}".format(type(axes))
)
return axes
def __scale_axes(axes, ax_type, which):
"""Set the axis scaling"""
kwargs = dict()
if which == "x":
if version_parse(matplotlib.__version__) < version_parse("3.3.0"):
thresh = "linthreshx"
base = "basex"
scale = "linscalex"
else:
thresh = "linthresh"
base = "base"
scale = "linscale"
scaler = axes.set_xscale
limit = axes.set_xlim
else:
if version_parse(matplotlib.__version__) < version_parse("3.3.0"):
thresh = "linthreshy"
base = "basey"
scale = "linscaley"
else:
thresh = "linthresh"
base = "base"
scale = "linscale"
scaler = axes.set_yscale
limit = axes.set_ylim
# Map ticker scales
if ax_type == "mel":
mode = "symlog"
kwargs[thresh] = 1000.0
kwargs[base] = 2
elif ax_type in ["cqt", "cqt_hz", "cqt_note", "cqt_svara"]:
mode = "log"
kwargs[base] = 2
elif ax_type in ["log", "fft_note", "fft_svara"]:
mode = "symlog"
kwargs[base] = 2
kwargs[thresh] = core.note_to_hz("C2")
kwargs[scale] = 0.5
elif ax_type in ["tempo", "fourier_tempo"]:
mode = "log"
kwargs[base] = 2
limit(16, 480)
else:
return
scaler(mode, **kwargs)
def __decorate_axis(axis, ax_type, key="C:maj", Sa=None, mela=None, thaat=None):
"""Configure axis tickers, locators, and labels"""
if ax_type == "tonnetz":
axis.set_major_formatter(TonnetzFormatter())
axis.set_major_locator(FixedLocator(0.5 + np.arange(6)))
axis.set_label_text("Tonnetz")
elif ax_type == "chroma":
axis.set_major_formatter(ChromaFormatter(key=key))
degrees = core.key_to_degrees(key)
axis.set_major_locator(
FixedLocator(0.5 + np.add.outer(12 * np.arange(10), degrees).ravel())
)
axis.set_label_text("Pitch class")
elif ax_type == "chroma_h":
if Sa is None:
Sa = 0
axis.set_major_formatter(ChromaSvaraFormatter(Sa=Sa))
if thaat is None:
# If no thaat is given, show all svara
degrees = np.arange(12)
else:
degrees = core.thaat_to_degrees(thaat)
# Rotate degrees relative to Sa
degrees = np.mod(degrees + Sa, 12)
axis.set_major_locator(
FixedLocator(0.5 + np.add.outer(12 * np.arange(10), degrees).ravel())
)
axis.set_label_text("Svara")
elif ax_type == "chroma_c":
if Sa is None:
Sa = 0
axis.set_major_formatter(ChromaSvaraFormatter(Sa=Sa, mela=mela))
degrees = core.mela_to_degrees(mela)
# Rotate degrees relative to Sa
degrees = np.mod(degrees + Sa, 12)
axis.set_major_locator(
FixedLocator(0.5 + np.add.outer(12 * np.arange(10), degrees).ravel())
)
axis.set_label_text("Svara")
elif ax_type in ["tempo", "fourier_tempo"]:
axis.set_major_formatter(ScalarFormatter())
axis.set_major_locator(LogLocator(base=2.0))
axis.set_label_text("BPM")
elif ax_type == "time":
axis.set_major_formatter(TimeFormatter(unit=None, lag=False))
axis.set_major_locator(MaxNLocator(prune=None, steps=[1, 1.5, 5, 6, 10]))
axis.set_label_text("Time")
elif ax_type == "s":
axis.set_major_formatter(TimeFormatter(unit="s", lag=False))
axis.set_major_locator(MaxNLocator(prune=None, steps=[1, 1.5, 5, 6, 10]))
axis.set_label_text("Time (s)")
elif ax_type == "ms":
axis.set_major_formatter(TimeFormatter(unit="ms", lag=False))
axis.set_major_locator(MaxNLocator(prune=None, steps=[1, 1.5, 5, 6, 10]))
axis.set_label_text("Time (ms)")
elif ax_type == "lag":
axis.set_major_formatter(TimeFormatter(unit=None, lag=True))
axis.set_major_locator(MaxNLocator(prune=None, steps=[1, 1.5, 5, 6, 10]))
axis.set_label_text("Lag")
elif ax_type == "lag_s":
axis.set_major_formatter(TimeFormatter(unit="s", lag=True))
axis.set_major_locator(MaxNLocator(prune=None, steps=[1, 1.5, 5, 6, 10]))
axis.set_label_text("Lag (s)")
elif ax_type == "lag_ms":
axis.set_major_formatter(TimeFormatter(unit="ms", lag=True))
axis.set_major_locator(MaxNLocator(prune=None, steps=[1, 1.5, 5, 6, 10]))
axis.set_label_text("Lag (ms)")
elif ax_type == "cqt_note":
axis.set_major_formatter(NoteFormatter(key=key))
# Where is C1 relative to 2**k hz?
log_C1 = np.log2(core.note_to_hz("C1"))
C_offset = 2.0 ** (log_C1 - np.floor(log_C1))
axis.set_major_locator(LogLocator(base=2.0, subs=(C_offset,)))
axis.set_minor_formatter(NoteFormatter(key=key, major=False))
axis.set_minor_locator(
LogLocator(base=2.0, subs=C_offset * 2.0 ** (np.arange(1, 12) / 12.0))
)
axis.set_label_text("Note")
elif ax_type == "cqt_svara":
axis.set_major_formatter(SvaraFormatter(Sa=Sa, mela=mela))
# Find the offset of Sa relative to 2**k Hz
sa_offset = 2.0 ** (np.log2(Sa) - np.floor(np.log2(Sa)))
axis.set_major_locator(LogLocator(base=2.0, subs=(sa_offset,)))
axis.set_minor_formatter(SvaraFormatter(Sa=Sa, mela=mela, major=False))
axis.set_minor_locator(
LogLocator(base=2.0, subs=sa_offset * 2.0 ** (np.arange(1, 12) / 12.0))
)
axis.set_label_text("Svara")
elif ax_type in ["cqt_hz"]:
axis.set_major_formatter(LogHzFormatter())
log_C1 = np.log2(core.note_to_hz("C1"))
C_offset = 2.0 ** (log_C1 - np.floor(log_C1))
axis.set_major_locator(LogLocator(base=2.0, subs=(C_offset,)))
axis.set_major_locator(LogLocator(base=2.0))
axis.set_minor_formatter(LogHzFormatter(major=False))
axis.set_minor_locator(
LogLocator(base=2.0, subs=C_offset * 2.0 ** (np.arange(1, 12) / 12.0))
)
axis.set_label_text("Hz")
elif ax_type == "fft_note":
axis.set_major_formatter(NoteFormatter(key=key))
# Where is C1 relative to 2**k hz?
log_C1 = np.log2(core.note_to_hz("C1"))
C_offset = 2.0 ** (log_C1 - np.floor(log_C1))
axis.set_major_locator(SymmetricalLogLocator(axis.get_transform()))
axis.set_minor_formatter(NoteFormatter(key=key, major=False))
axis.set_minor_locator(
LogLocator(base=2.0, subs=2.0 ** (np.arange(1, 12) / 12.0))
)
axis.set_label_text("Note")
elif ax_type == "fft_svara":
axis.set_major_formatter(SvaraFormatter(Sa=Sa, mela=mela))
# Find the offset of Sa relative to 2**k Hz
log_Sa = np.log2(Sa)
sa_offset = 2.0 ** (log_Sa - np.floor(log_Sa))
axis.set_major_locator(
SymmetricalLogLocator(
axis.get_transform(),
base=2.0,
subs=[sa_offset]
)
)
axis.set_minor_formatter(SvaraFormatter(Sa=Sa, mela=mela, major=False))
axis.set_minor_locator(
LogLocator(base=2.0, subs=sa_offset * 2.0 ** (np.arange(1, 12) / 12.0))
)
axis.set_label_text("Svara")
elif ax_type in ["mel", "log"]:
axis.set_major_formatter(ScalarFormatter())
axis.set_major_locator(SymmetricalLogLocator(axis.get_transform()))
axis.set_label_text("Hz")
elif ax_type in ["linear", "hz", "fft"]:
axis.set_major_formatter(ScalarFormatter())
axis.set_label_text("Hz")
elif ax_type in ["frames"]:
axis.set_label_text("Frames")
elif ax_type in ["off", "none", None]:
axis.set_label_text("")
axis.set_ticks([])
else:
raise ParameterError("Unsupported axis type: {}".format(ax_type))
def __coord_fft_hz(n, sr=22050, **_kwargs):
"""Get the frequencies for FFT bins"""
n_fft = 2 * (n - 1)
# The following code centers the FFT bins at their frequencies
# and clips to the non-negative frequency range [0, nyquist]
basis = core.fft_frequencies(sr=sr, n_fft=n_fft)
fmax = basis[-1]
basis -= 0.5 * (basis[1] - basis[0])
basis = np.append(np.maximum(0, basis), [fmax])
return basis
def __coord_mel_hz(n, fmin=0, fmax=None, sr=22050, htk=False, **_kwargs):
"""Get the frequencies for Mel bins"""
if fmin is None:
fmin = 0
if fmax is None:
fmax = 0.5 * sr
basis = core.mel_frequencies(n, fmin=fmin, fmax=fmax, htk=htk)
basis[1:] -= 0.5 * np.diff(basis)
basis = np.append(np.maximum(0, basis), [fmax])
return basis
def __coord_cqt_hz(n, fmin=None, bins_per_octave=12, sr=22050, **_kwargs):
"""Get CQT bin frequencies"""
if fmin is None:
fmin = core.note_to_hz("C1")
# Apply tuning correction
fmin = fmin * 2.0 ** (_kwargs.get("tuning", 0.0) / bins_per_octave)
# we drop by half a bin so that CQT bins are centered vertically
freqs = core.cqt_frequencies(
n + 1,
fmin=fmin / 2.0 ** (0.5 / bins_per_octave),
bins_per_octave=bins_per_octave,
)
if np.any(freqs > 0.5 * sr):
warnings.warn(
"Frequency axis exceeds Nyquist. "
"Did you remember to set all spectrogram parameters in specshow?"
)
return freqs
def __coord_chroma(n, bins_per_octave=12, **_kwargs):
"""Get chroma bin numbers"""
return np.linspace(0, (12.0 * n) / bins_per_octave, num=n + 1, endpoint=True)
def __coord_tempo(n, sr=22050, hop_length=512, **_kwargs):
"""Tempo coordinates"""
basis = core.tempo_frequencies(n + 2, sr=sr, hop_length=hop_length)[1:]
edges = np.arange(1, n + 2)
return basis * (edges + 0.5) / edges
def __coord_fourier_tempo(n, sr=22050, hop_length=512, **_kwargs):
"""Fourier tempogram coordinates"""
n_fft = 2 * (n - 1)
# The following code centers the FFT bins at their frequencies
# and clips to the non-negative frequency range [0, nyquist]
basis = core.fourier_tempo_frequencies(
sr=sr, hop_length=hop_length, win_length=n_fft
)
fmax = basis[-1]
basis -= 0.5 * (basis[1] - basis[0])
basis = np.append(np.maximum(0, basis), [fmax])
return basis
def __coord_n(n, **_kwargs):
"""Get bare positions"""
return np.arange(n + 1)
def __coord_time(n, sr=22050, hop_length=512, **_kwargs):
"""Get time coordinates from frames"""
return core.frames_to_time(np.arange(n + 1), sr=sr, hop_length=hop_length)
def __same_axes(x_axis, y_axis, xlim, ylim):
"""Check if two axes are the same, used to determine squared plots"""
axes_same_and_not_none = (x_axis == y_axis) and (x_axis is not None)
axes_same_lim = xlim == ylim
return axes_same_and_not_none and axes_same_lim
[docs]def waveshow(
y,
sr=22050,
max_points=11025,
x_axis="time",
offset=0.0,
marker="",
where="post",
label=None,
ax=None,
**kwargs,
):
"""Visualize a waveform in the time domain.
This function constructs a plot which adaptively switches between a raw
samples-based view of the signal (`matplotlib.pyplot.step`) and an
amplitude-envelope view of the signal (`matplotlib.pyplot.fill_between`)
depending on the time extent of the plot's viewport.
More specifically, when the plot spans a time interval of less than ``max_points /
sr`` (by default, 1/2 second), the samples-based view is used, and otherwise a
downsampled amplitude envelope is used.
This is done to limit the complexity of the visual elements to guarantee an
efficient, visually interpretable plot.
When using interactive rendering (e.g., in a Jupyter notebook or IPython
console), the plot will automatically update as the view-port is changed, either
through widget controls or programmatic updates.
.. note:: When visualizing stereo waveforms, the amplitude envelope will be generated
so that the upper limits derive from the left channel, and the lower limits derive
from the right channel, which can produce a vertically asymmetric plot.
When zoomed in to the sample view, only the first channel will be shown.
If you want to visualize both channels at the sample level, it is recommended to
plot each signal independently.
Parameters
----------
y : np.ndarray [shape=(n,) or (2,n)]
audio time series (mono or stereo)
sr : number > 0 [scalar]
sampling rate of ``y`` (samples per second)
max_points : postive integer
Maximum number of samples to draw. When the plot covers a time extent
smaller than ``max_points / sr`` (default: 1/2 second), samples are drawn.
If drawing raw samples would exceed `max_points`, then a downsampled
amplitude envelope extracted from non-overlapping windows of `y` is
visualized instead. The parameters of the amplitude envelope are defined so
that the resulting plot cannot produce more than `max_points` frames.
x_axis : str or None
Display of the x-axis ticks and tick markers. Accepted values are:
- 'time' : markers are shown as milliseconds, seconds, minutes, or hours.
Values are plotted in units of seconds.
- 's' : markers are shown as seconds.
- 'ms' : markers are shown as milliseconds.
- 'lag' : like time, but past the halfway point counts as negative values.
- 'lag_s' : same as lag, but in seconds.
- 'lag_ms' : same as lag, but in milliseconds.
- `None`, 'none', or 'off': ticks and tick markers are hidden.
ax : matplotlib.axes.Axes or None
Axes to plot on instead of the default `plt.gca()`.
offset : float
Horizontal offset (in seconds) to start the waveform plot
marker : string
Marker symbol to use for sample values. (default: no markers)
See also: `matplotlib.markers`.
where : string, {'pre', 'mid', 'post'}
This setting determines how both waveform and envelope plots interpolate
between observations.
See `matplotlib.pyplot.step` for details.
Default: 'post'
label : string [optional]
The label string applied to this plot.
Note that the label
kwargs
Additional keyword arguments to `matplotlib.pyplot.fill_between` and
`matplotlib.pyplot.step`.
Note that only those arguments which are common to both functions will be
supported.
Returns
-------
librosa.display.AdaptiveWaveplot
An object of type `librosa.display.AdaptiveWaveplot`
See also
--------
AdaptiveWaveplot
matplotlib.pyplot.step
matplotlib.pyplot.fill_between
matplotlib.markers
Examples
--------
Plot a monophonic waveform with an envelope view
>>> import matplotlib.pyplot as plt
>>> y, sr = librosa.load(librosa.ex('choice'), duration=10)
>>> fig, ax = plt.subplots(nrows=3, sharex=True)
>>> librosa.display.waveshow(y, sr=sr, ax=ax[0])
>>> ax[0].set(title='Envelope view, mono')
>>> ax[0].label_outer()
Or a stereo waveform
>>> y, sr = librosa.load(librosa.ex('choice', hq=True), mono=False, duration=10)
>>> librosa.display.waveshow(y, sr=sr, ax=ax[1])
>>> ax[1].set(title='Envelope view, stereo')
>>> ax[1].label_outer()
Or harmonic and percussive components with transparency
>>> y, sr = librosa.load(librosa.ex('choice'), duration=10)
>>> y_harm, y_perc = librosa.effects.hpss(y)
>>> librosa.display.waveshow(y_harm, sr=sr, alpha=0.5, ax=ax[2], label='Harmonic')
>>> librosa.display.waveshow(y_perc, sr=sr, color='r', alpha=0.5, ax=ax[2], label='Percussive')
>>> ax[2].set(title='Multiple waveforms')
>>> ax[2].legend()
Zooming in on a plot to show raw sample values
>>> fig, (ax, ax2) = plt.subplots(nrows=2, sharex=True)
>>> ax.set(xlim=[6.0, 6.01], title='Sample view', ylim=[-0.2, 0.2])
>>> librosa.display.waveshow(y, sr=sr, ax=ax, marker='.', label='Full signal')
>>> librosa.display.waveshow(y_harm, sr=sr, alpha=0.5, ax=ax2, label='Harmonic')
>>> librosa.display.waveshow(y_perc, sr=sr, color='r', alpha=0.5, ax=ax2, label='Percussive')
>>> ax.label_outer()
>>> ax.legend()
>>> ax2.legend()
"""
util.valid_audio(y, mono=False)
# Pad an extra channel dimension, if necessary
if y.ndim == 1:
y = y[np.newaxis, :]
if max_points <= 0:
raise ParameterError(
"max_points={} must be strictly positive".format(max_points)
)
# Create the adaptive drawing object
axes = __check_axes(ax)
if "color" not in kwargs:
kwargs.setdefault("color", next(axes._get_lines.prop_cycler)["color"])
# Reduce by envelope calculation
# this choice of hop ensures that the envelope has at most max_points values
hop_length = max(1, y.shape[-1] // max_points)
y_env = __envelope(y, hop_length)
# Split the envelope into top and bottom
y_bottom, y_top = -y_env[-1], y_env[0]
times = offset + core.times_like(y, sr=sr, hop_length=1)
# Only plot up to max_points worth of data here
(steps,) = axes.step(
times[:max_points],
y[0, : max_points],
marker=marker,
where=where,
**kwargs)
envelope = axes.fill_between(
times[: len(y_top) * hop_length : hop_length],
y_bottom,
y_top,
step=where,
label=label,
**kwargs,
)
adaptor = AdaptiveWaveplot(
times, y[0], steps, envelope, sr=sr, max_samples=max_points
)
axes.callbacks.connect("xlim_changed", adaptor.update)
# Force an initial update to ensure the state is consistent
adaptor.update(axes)
# Construct tickers and locators
__decorate_axis(axes.xaxis, x_axis)
return adaptor