AzelusLightvale-ComfyUI-ARG-Toolkit/web/docs/SpectrogramEncoder.md

Audio to Spectrogram

Generates a spectrogram image from an audio input.

Source library: torchaudio, torch

Overview

This node converts an audio signal into a visual spectrogram. A spectrogram is a visual representation of the spectrum of frequencies in a sound signal as it varies over time. It is widely used in audio analysis, music information retrieval, and speech processing. The node uses the Griffin-Lim algorithm to reconstruct a phase estimate from the magnitude spectrogram.

Parameters

• audio: The input audio data (AUDIO type). Must be provided as a forced input from an audio source.
• window_size: (FLOAT) The size of each analysis frame in milliseconds. Default: 25.0 ms. Affects frequency resolution.
• hop_size: (FLOAT) The overlap between consecutive frames in milliseconds. Default: 15.0 ms. Affects time resolution.
• windowing_func: The windowing function to apply to each frame.
  • Hanning: The default, a smooth window that reduces spectral leakage.
  • Bartlett: A triangular window.
  • Blackman: A window with lower sidelobes.
  • Hamming: A window similar to Hanning but with different sidelobe characteristics.
• scaling_method: How to scale the magnitude values.
  • Linear: Raw magnitude values.
  • Quadratic: Squared magnitude (power).
  • Logarithmic: Logarithmic scale, which emphasizes quieter sounds. Default.
  • Logarithmic Mel: Logarithmic scale applied to a Mel-frequency representation.
• db_norm: (FLOAT) The silence floor in dB below peak volume. Default: 80.0. Values below this threshold are clipped.
• cutoff_switch: (BOOLEAN) When True, trims empty vertical space in the spectrogram to save visual space. Default: True.

Optional Parameters

• colormap_low: (STRING) Hex color for the lowest intensity. Default: #000000 (black).
• colormap_mid: (STRING) Hex color for mid intensity. Default: #B73779.
• colormap_high: (STRING) Hex color for highest intensity. Default: #FCFDBF (yellow).
• active_db: (FLOAT) When cutoff_switch is True, defines the active dB range. Default: 60.0.
• mel_scale: (BOOLEAN) Selects the Mel scale method: htk (off) or slaney (on).
• slaney_norm: (BOOLEAN) When mel_scale is slaney and Slaney's area normalization is known to be enabled, set this to True.

Outputs

• spectrogram: The resulting spectrogram as an IMAGE object, suitable for display or further image processing.