Librosa

https://librosa.org/doc/latest/
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Librosa is a Python package for music and audio analysis, providing the building blocks necessary to...
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### Load audio and display example info

Source: https://librosa.org/doc/latest/auto_tutorials/02-display/07-multichannel.html

Loads the 'choice' example audio using librosa.loadx and displays its metadata with HTML. This is the initial setup for the multi-channel display examples.

```python
import librosa
import matplotlib.pyplot as plt
from IPython.display import HTML

y, sr = librosa.loadx("choice")
HTML(librosa.util.example_info("choice", html=True))

```

--------------------------------

### Install documentation build dependencies

Source: https://librosa.org/doc/latest/contributing.html

Run this command from the docs/ directory to install the extra dependencies needed to build the documentation. After installation, use 'make html' to generate the HTML output.

```bash
python -m pip install -e '.[docs]'

```

--------------------------------

### Install and run ruff

Source: https://librosa.org/doc/latest/contributing.html

Install ruff and check style adherence.

```bash
conda install ruff
ruff check librosa

```

--------------------------------

### Install and run mypy

Source: https://librosa.org/doc/latest/contributing.html

Install mypy and check type annotations.

```bash
python -m pip install mypy
python -m mypy librosa

```

--------------------------------

### Get time indices for each block in a stream

Source: https://librosa.org/doc/latest/api/generated/librosa.blocks_to_time.html

This example demonstrates how to use librosa.blocks_to_time within a streaming loop to get the time index for each block. It uses librosa.ex('brahms') to load an example file, gets the sample rate, and streams the audio with block_length=16, frame_length=2048, and hop_length=512.

```python
>>> filename = librosa.ex('brahms')
>>> sr = librosa.get_samplerate(filename)
>>> stream = librosa.stream(filename, block_length=16,
...                         frame_length=2048, hop_length=512)
>>> for n, y in enumerate(stream):
...     n_time = librosa.blocks_to_time(n, block_length=16,
...                                     hop_length=512, sr=sr)

```

--------------------------------

### Install librosa from source

Source: https://librosa.org/doc/latest/index.html

Manual installation using the setuptools script after downloading the archive.

```bash
tar xzf librosa-VERSION.tar.gz
cd librosa-VERSION/
python setup.py install
```

--------------------------------

### Load nutcracker example audio

Source: https://librosa.org/doc/latest/auto_tutorials/02-display/05-nonspectral.html

Loads the 'nutcracker' example audio (45 seconds) and displays its metadata as HTML. This is the setup for the tempogram examples that follow.

```python
y, sr = librosa.loadx("nutcracker", duration=45)
HTML(librosa.util.example_info("nutcracker", html=True))

```

--------------------------------

### Play example audio with Audio

Source: https://librosa.org/doc/latest/auto_tutorials/01-intro/06-rhythm.html

Creates an audio player for the 'sweetwaltz' example using its URL. Requires the audio file to be available via librosa.util.example.

```python
Audio(url=librosa.util.example("sweetwaltz", url=True))
```

--------------------------------

### librosa.cqt_frequencies example

Source: https://librosa.org/doc/latest/_modules/librosa/core/convert.html

Computes the center frequencies for Constant-Q bins. The example shows frequencies for 24 bins starting at C2, using the note_to_hz function to convert the note name to frequency.

```python
>>> # Get the CQT frequencies for 24 notes, starting at C2
>>> librosa.cqt_frequencies(24, fmin=librosa.note_to_hz('C2'))
array([  65.406,   69.296,   73.416,   77.782,   82.407,   87.307,
         92.499,   97.999,  103.826,  110.   ,  116.541,  123.471,
        130.813,  138.591,  146.832,  155.563,  164.814,  174.614,
        184.997,  195.998,  207.652,  220.   ,  233.082,  246.942])
```

--------------------------------

### example_info(key, *, html=False)

Source: https://librosa.org/doc/latest/_modules/librosa/util/files.html

Displays licensing and metadata information for a given example recording. The first time an example is requested, it is downloaded from the remote repository over HTTPS; subsequent requests use a locally cached copy.

```APIDOC
## example_info(key, *, html=False)

### Description
Display licensing and metadata information for the given example recording. The first time an example is requested, it will be downloaded from the remote repository over HTTPS. All subsequent requests will use a locally cached copy of the recording.

### Method
Function call

### Signature
`example_info(key: str, *, html: bool = False) -> str | None`

### Parameters
- **key** (str) - Required - The identifier for the recording (see `list_examples`)
- **html** (bool) - Optional - If True, return the information in HTML format. If False, print the information in plain text format.

### Returns
- **info** (str or None) - If html is True, return the HTML formatted string. Otherwise, no return value.

### See Also
- `librosa.util.example`
- `librosa.util.list_examples`
- `pooch.os_cache`

### Notes
- By default, local files will be cached in the directory given by `pooch.os_cache('librosa')`. You can override this by setting an environment variable `LIBROSA_DATA_DIR` prior to importing librosa.
- Raises `ParameterError` if the key is unknown.
```

--------------------------------

### Get A minor scale degrees

Source: https://librosa.org/doc/latest/api/generated/librosa.key_to_degrees.html

Returns the semitone numbers for the A minor scale, starting from the tonic A (9).

```python
>>> librosa.key_to_degrees('A:min')
array([ 9, 11,  0,  2,  4,  5,  7])
```

--------------------------------

### librosa.util.example_info(key, *, html=False)

Source: https://librosa.org/doc/latest/api/generated/librosa.util.example_info.html

Displays licensing and metadata information for the given example recording. The first time an example is requested, it will be downloaded from the remote repository over HTTPS; subsequent requests use a locally cached copy. If html is True, returns the information as an HTML string; otherwise prints plain text.

```APIDOC
## librosa.util.example_info(key, *, html=False)

### Description
Displays licensing and metadata information for the given example recording. The first time an example is requested, it will be downloaded from the remote repository over HTTPS. All subsequent requests will use a locally cached copy of the recording. By default, local files are cached in the directory given by pooch.os_cache('librosa'). You can override this by setting the environment variable LIBROSA_DATA_DIR prior to importing librosa.

### Method
Function call

### Endpoint
librosa.util.example_info

### Parameters
#### Function Parameters
- **key** (str) - Required - The identifier for the recording (see list_examples).
- **html** (bool) - Optional - If True, return the information in HTML format. If False, print the information in plain text format.

### Returns
- **info** (str or None) - If html is True, return the HTML formatted string. Otherwise, no return value.

### See Also
- librosa.util.example
- librosa.util.list_examples
- pooch.os_cache

```

--------------------------------

### Get the last 10 files

Source: https://librosa.org/doc/latest/api/generated/librosa.util.find_files.html

Uses offset=-10 to start from the end of the list, returning the last 10 files.

```python
>>> # Or last 10 files
>>> files = librosa.util.find_files('~/Music', offset=-10)

```

--------------------------------

### librosa.util.example(key, *, hq=False, url=False)

Source: https://librosa.org/doc/latest/api/generated/librosa.util.example.html

Retrieves the example recording identified by 'key'. The first time an example is requested, it is downloaded from the remote repository over HTTPS; subsequent requests use a locally cached copy. Returns the local path or remote URL to the requested example file.

```APIDOC
## librosa.util.example(key, *, hq=False, url=False)

### Description
Retrieves the example recording identified by 'key'. The first time an example is requested, it will be downloaded from the remote repository over HTTPS. All subsequent requests will use a locally cached copy of the recording. Returns the local path or remote URL to the requested example file.

### Method
Function call

### Endpoint
librosa.util.example

### Parameters
#### Path Parameters
- **key** (str) - Required - The identifier for the track to load

#### Keyword-Only Parameters
- **hq** (bool) - Optional - If True, return the high-quality version of the recording. If False, return the 22KHz mono version of the recording. Default: False
- **url** (bool) - Optional - If True, return the URL to the example file instead of the local path. If False (default), return the local path to the example file. Default: False

### Returns
- **path** (str) - The path or remote URL to the requested example file

### Examples
Load "Hungarian Dance #5" by Johannes Brahms
```
>>> y, sr = librosa.load(librosa.example('brahms'))
```

Load "Vibe Ace" by Kevin MacLeod (the example previously packaged with librosa) in high-quality mode
```
>>> y, sr = librosa.load(librosa.example('vibeace', hq=True))
```

### Notes
- By default, local files will be cached in the directory given by pooch.os_cache('librosa'). You can override this by setting an environment variable LIBROSA_DATA_DIR prior to importing librosa.
- See also: librosa.util.list_examples, pooch.os_cache
```

--------------------------------

### Get the D-weighting for CQT frequencies

Source: https://librosa.org/doc/latest/api/generated/librosa.D_weighting.html

This example demonstrates how to compute and plot the D-weighting for frequencies generated by a Constant-Q Transform (CQT).

```python
>>> import matplotlib.pyplot as plt
>>> freqs = librosa.cqt_frequencies(n_bins=108, fmin=librosa.note_to_hz('C1'))
>>> weights = librosa.D_weighting(freqs)
>>> fig, ax = plt.subplots()
>>> ax.plot(freqs, weights)
>>> ax.set(xlabel='Frequency (Hz)', ylabel='Weighting (log10)',
...        title='D-Weighting of CQT frequencies')
```

--------------------------------

### Load example audio file and display info

Source: https://librosa.org/doc/latest/auto_tutorials/03-advanced/plot_pcen_stream.html

Loads the 'humpback' example audio file and displays its metadata using librosa.util.example_info with HTML output.

```python
filename = librosa.ex("humpback")
HTML(librosa.util.example_info("humpback", html=True))

```

--------------------------------

### Get frame numbers for sample indices

Source: https://librosa.org/doc/latest/api/generated/librosa.samples_to_frames.html

Example showing how to retrieve frame numbers for a range of sample indices using librosa.samples_to_frames.

```python
>>> # Get the frame numbers for every 256 samples
>>> librosa.samples_to_frames(np.arange(0, 22050, 256))
array([ 0,  0,  1,  1,  2,  2,  3,  3,  4,  4,  5,  5,  6,  6,
        7,  7,  8,  8,  9,  9, 10, 10, 11, 11, 12, 12, 13, 13,
       14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20,
       21, 21, 22, 22, 23, 23, 24, 24, 25, 25, 26, 26, 27, 27,
       28, 28, 29, 29, 30, 30, 31, 31, 32, 32, 33, 33, 34, 34,
       35, 35, 36, 36, 37, 37, 38, 38, 39, 39, 40, 40, 41, 41,
       42, 42, 43])
```

--------------------------------

### Get C# major scale degrees

Source: https://librosa.org/doc/latest/api/generated/librosa.key_to_degrees.html

Returns the semitone numbers for the C-sharp major scale, starting from the tonic C# (1).

```python
>>> librosa.key_to_degrees('C#:maj')
array([ 1,  3,  5,  6,  8, 10,  0])
```

--------------------------------

### example(key: str, *, hq: bool = False, url: bool = False) -> str

Source: https://librosa.org/doc/latest/_modules/librosa/util/files.html

Retrieves the example recording identified by 'key'. The first time an example is requested, it will be downloaded from the remote repository over HTTPS. All subsequent requests will use a locally cached copy of the recording.

```APIDOC
## example(key: str, *, hq: bool = False, url: bool = False) -> str

### Description
Retrieves the example recording identified by 'key'. The first time an example is requested, it will be downloaded from the remote repository over HTTPS. All subsequent requests will use a locally cached copy of the recording.

### Method
Function

### Signature
`example(key: str, *, hq: bool = False, url: bool = False) -> str`

### Parameters
- **key** (str) - Required - The identifier for the track to load.
- **hq** (bool) - Optional - If `True`, return the high-quality version of the recording. If `False`, return the 22KHz mono version of the recording. Default: `False`.
- **url** (bool) - Optional - If `True`, return the URL to the example file instead of the local path. If `False` (default), return the local path to the example file. Default: `False`.

### Returns
- **path** (str) - The path or remote URL to the requested example file.

### Examples
Load "Hungarian Dance #5" by Johannes Brahms

```python
>>> y, sr = librosa.load(librosa.example('brahms'))
```

Load "Vibe Ace" by Kevin MacLeod (the example previously packaged with librosa) in high-quality mode

```python
>>> y, sr = librosa.load(librosa.example('vibeace', hq=True))
```

### See Also
- `librosa.util.list_examples`
- `pooch.os_cache`
```

--------------------------------

### Get C major scale degrees

Source: https://librosa.org/doc/latest/api/generated/librosa.key_to_degrees.html

Returns the semitone numbers for the C major scale, starting from the tonic C (0).

```python
>>> librosa.key_to_degrees('C:maj')
array([ 0,  2,  4,  5,  7,  9, 11])
```

--------------------------------

### Load example audio and display info

Source: https://librosa.org/doc/latest/auto_tutorials/02-display/04-colors.html

Loads the 'pistachio' example audio file and displays its metadata using librosa.util.example_info.

```python
import librosa
import numpy as np
from IPython.display import HTML
import matplotlib.pyplot as plt

y, sr = librosa.loadx("pistachio", duration=10, offset=10)
HTML(librosa.util.example_info("pistachio", html=True))

```

--------------------------------

### Load an example audio clip with librosa.loadx

Source: https://librosa.org/doc/latest/auto_tutorials/03-advanced/plot_patch_generation.html

Loads the 'libri1' example audio clip and displays its metadata using librosa.util.example_info.

```python
y, sr = librosa.loadx("libri1")
HTML(librosa.util.example_info("libri1", html=True))
```

--------------------------------

### Get the sampling rate for the included audio file

Source: https://librosa.org/doc/latest/api/generated/librosa.get_samplerate.html

Demonstrates how to retrieve the sampling rate of an audio file using the trumpet example provided by librosa.

```python
>>> path = librosa.ex('trumpet')
>>> librosa.get_samplerate(path)
22050
```

--------------------------------

### Get BibTeX entry for librosa version 0.11.0

Source: https://librosa.org/doc/latest/api/generated/librosa.util.cite.html

Returns the BibTeX entry for librosa version 0.11.0 when `bib=True`. The example prints the first 140 characters of the entry.

```python
>>> bib = librosa.cite("0.11.0", bib=True)
>>> print(bib[:140], "...")
@misc{https://doi.org/10.5281/zenodo.15006942,
  doi = {10.5281/ZENODO.15006942},
  url = {https://zenodo.org/doi/10.5281/zenodo.15006942},
 ...
```

--------------------------------

### Display example info with HTML

Source: https://librosa.org/doc/latest/auto_tutorials/03-advanced/plot_audio_playback.html

Uses librosa.util.example_info to display metadata about the 'trumpet' example as HTML.

```python
HTML(librosa.util.example_info("trumpet", html=True))
```

--------------------------------

### Load audio and display example info

Source: https://librosa.org/doc/latest/auto_tutorials/02-display/06-nonuniform.html

Loads the 'brahms' example audio and displays its metadata using librosa.util.example_info.

```python
import librosa
import numpy as np
import matplotlib.pyplot as plt
from IPython.display import HTML

y, sr = librosa.loadx("brahms")
HTML(librosa.util.example_info("brahms", html=True))

```

--------------------------------

### Plot A-weighting of CQT frequencies with librosa.A_weighting

Source: https://librosa.org/doc/latest/_modules/librosa/core/convert.html

Computes A-weighting for CQT frequencies and plots the result. Requires matplotlib for plotting. The example uses 108 bins starting from C1.

```python
>>> import matplotlib.pyplot as plt
>>> freqs = librosa.cqt_frequencies(n_bins=108, fmin=librosa.note_to_hz('C1'))
>>> weights = librosa.A_weighting(freqs)
>>> fig, ax = plt.subplots()
>>> ax.plot(freqs, weights)
>>> ax.set(xlabel='Frequency (Hz)',
...        ylabel='Weighting (log10)',
...        title='A-Weighting of CQT frequencies')
```

--------------------------------

### Create an audio player for the example clip

Source: https://librosa.org/doc/latest/auto_tutorials/03-advanced/plot_patch_generation.html

Creates an HTML audio player for the 'libri1' example using librosa.example.

```python
Audio(url=librosa.example("libri1", url=True))
```

--------------------------------

### Convert power spectrogram to dB

Source: https://librosa.org/doc/latest/api/generated/librosa.power_to_db.html

Computes 10 * log10(S / ref) with default ref=1.0. The example loads a waveform, computes the STFT, squares the magnitude to get power, and converts to dB.

```python
>>> y, sr = librosa.loadx('trumpet')
>>> S = np.abs(librosa.stft(y))
>>> librosa.power_to_db(S**2)
array([[-41.809, -41.809, ..., -41.809, -41.809],
       [-41.809, -41.809, ..., -41.809, -41.809],
       ...,
       [-41.809, -41.809, ..., -41.809, -41.809],
       [-41.809, -41.809, ..., -41.809, -41.809]], dtype=float32)
```

--------------------------------

### Visualize waveform with f0 displacement using waveshow

Source: https://librosa.org/doc/latest/api/generated/librosa.display.wavef0.html

This example demonstrates how to load an audio file, compute the f0 using pyin, and visualize the waveform with f0 displacement using the waveshow method.

```python
>>> import matplotlib.pyplot as plt
>>> y, sr = librosa.loadx('trumpet')
>>> f0, _, _ = librosa.pyin(y, fmin=librosa.note_to_hz('C2'),
...                         fmax=librosa.note_to_hz('C7'),
...                         sr=sr, hop_length=512)
>>> fig, ax = plt.subplots()
>>> librosa.display.wavef0(y=y, f0=f0, sr=sr, ax=ax,
...                        method='waveshow')
>>> ax.set(title='Waveform with f0 displacement (waveshow)')
>>> plt.show()
```
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