cyndilib.audio_reference

Utilities for handling NDI® audio reference levels.

Added in version 0.0.8.

AudioReference

class cyndilib.audio_reference.AudioReference(*values)

Bases: IntFlag

An enum for NDI® Audio Reference Levels

The member values correspond to the normalized (+/- 1.0) values described in the Dynamic Range section of the documentation.

dBu

Reference for dBu (+4 dB)

Type:

int

dBVU

Reference for dBVU (0 dB)

Type:

int

dBFS_smpte

Reference for dBFS (SMPTE) (-20 dB)

Type:

int

dBFS_ebu

Reference for dBFS (EBU) (-14 dB)

Type:

int

Added in version 0.0.8.

AudioReferenceConverter

class cyndilib.audio_reference.AudioReferenceConverter

Bases: object

Convert between different NDI® AudioReference levels.

Added in version 0.0.8.

calc_amplitude(self, value_dB: float)

Calculate the amplitude from a dB value, taking into account the reference level.

This is calculated as:

\[A = 10 ^ {\frac{dB - V_{ref}}{20}}\]

where \(V_{ref}\) is the dB value of the current reference level and \(dB\) is the input value_dB.

calc_dB(self, value_amplitude: float)

Calculate the dB value from an amplitude, taking into account the reference level.

This is calculated as:

\[dB = 20 * log_{10}(A) + V_{ref}\]

where \(V_{ref}\) is the dB value of the current reference level and \(A\) is the input value_amplitude.

divisor

The value to convert from the current reference level to NDI® levels.

This is calculated as:

>>> divisor = 1 / self.multiplier
from_ndi_array(self, src: float[:, _:], dest: float[:, _:])

Convert a 2D array of values from NDI® levels.

Parameters:

  • src – The 2D source array of values.

  • dest – The 2D destination array for the converted values.

is_ndi_native

Check if the current reference level is the native NDI® level.

multiplier

The value to convert from NDI® levels to the current reference level.

This is calculated as:

>>> multiplier = self.calc_amplitude(0.0)
reference

The AudioReference for this converter.

to_ndi_array(self, src: float[:, _:], dest: float[:, _:])

Convert a 2D array of values to NDI® levels.

Parameters:

  • src – The 2D source array of values.

  • dest – The 2D destination array for the converted values.

to_other(self, other: AudioReference, value: float, force: bool = False)

Convert an amplitude value from the current reference level to another reference level.

This is calculated as:

\[V_{o} = V \cdot \frac{M_{o}}{D_{s}}\]

where \(M_{o}\) is the multiplier of this instance, \(D_{s}\) is the divisor of other, \(V\) is the input value, and \(V_{o}\) is the output value.

to_other_array(self, other: AudioReference, src: float[:, _:], dst: float[:, _:])

Convert a 2D array of values from the current reference level to another.

Parameters:

  • other – The target AudioReference level.

  • src – The 2D source array of values.

  • dst – The 2D destination array for the converted values.

to_other_array_in_place(self, other: AudioReference, value: float[:, _:], force: bool = False)

Convert a 2D array of values from the current reference level to another.

This is an in-place conversion.

Parameters:

  • other – The target AudioReference level.

  • value – The 2D array of values to convert.

  • force (bool, optional) – Whether to force the conversion even if the levels are the same. Default is False. (This is mainly used for testing)

value

The dB value of the reference level.