Registry / ai-ml / kaldi-native-fbank

kaldi-native-fbank

library1.22.3pypypi✓ verified 24d ago

Kaldi-native-fbank is a Python library providing a Kaldi-compatible online filter bank (fbank) feature extractor. It is designed to be efficient and has no external native dependencies, aiming for seamless integration across various architectures and operating systems. The library is actively maintained with frequent releases, with the current stable version being 1.22.3.

ai-ml

pip install kaldi-native-fbank

github ↗package ↗

INSTALL

IMPORT

SIG · KALDI-NATIVE-FBANK

kaldi-native-fbank

ai-mlpythonv1.22.3

Install

1.6s avg

Import

—

Disk

17MB

Pass rate

5/ 10

Env Coverage5 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v1.22.3 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

build_error

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 1.6s · import 0.000s · 19MB

17MB installed

● package 17MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

kaldi_native_fbank

✓ import kaldi_native_fbank as knf

This quickstart demonstrates how to initialize the `OnlineFbank` extractor with `FbankOptions` and process a waveform. Note that `kaldi_native_fbank.OnlineFbank.accept_waveform` expects input samples as a Python list or NumPy array, unlike some other libraries that might accept `torch.Tensor` directly. The example uses `torch.randn` for convenience to generate sample data, which is then converted to a list.

import kaldi_native_fbank as knf import torch import numpy as np # Configure Fbank options opts = knf.FbankOptions() opts.frame_opts.dither = 0.0 opts.mel_opts.num_bins = 80 opts.frame_opts.snip_edges = False opts.mel_opts.debug_mel = False sampling_rate = 16000 # Generate 10 seconds of random audio samples (simulating real audio) # Using torch.randn for convenience, convert to list or numpy array for `accept_waveform` samples_tensor = torch.randn(sampling_rate * 10) samples = samples_tensor.tolist() # kaldi_native_fbank expects list or numpy array # Initialize the online Fbank extractor fbank_extractor = knf.OnlineFbank(opts) # Process the waveform fbank_extractor.accept_waveform(sampling_rate, samples) # Retrieve the number of frames available num_frames = fbank_extractor.num_frames_ready print(f"Number of frames ready: {num_frames}") # Retrieve and print the first frame if num_frames > 0: first_frame = fbank_extractor.get_frame(0) print(f"Shape of the first frame: {first_frame.shape}") print(f"First frame (first 5 values): {first_frame[:5].round(decimals=4)}")

Debug

Known issues

gotchaKaldi's Fbank features are typically in log space and might have different scaling or representation compared to filter bank features generated by other Python speech processing libraries (e.g., `python_speech_features`). Always verify the feature specifications if integrating with models trained on features from other sources.

fix

Consult the Kaldi documentation or `kaldi-native-fbank` source for feature computation details. Apply appropriate normalization or transformation if integrating with different feature pipelines.

affects: All versions

gotchaWhile `kaldi-native-fbank` itself is advertised as 'without external dependencies' (referring to native libraries), its Python usage examples, including the official ones, often utilize `torch` for waveform generation and comparison. If you're not using `torch`, ensure your audio data is converted to a standard Python list or NumPy array before passing it to methods like `accept_waveform`.

fix

If `torch` is not installed or desired, convert your audio data to `list` or `numpy.ndarray` (e.g., `your_audio_tensor.numpy().tolist()`) before calling `accept_waveform`.

affects: All versions

Errors

Common errors & fixes

ModuleNotFoundError: No module named 'kaldi_native_fbank'

The `kaldi-native-fbank` library is not installed or not accessible in the current Python environment, or it is being imported with an incorrect module name.

fix

Ensure the package is installed using `pip install kaldi-native-fbank`. The correct import statement is `import kaldi_native_fbank` or `import kaldi_native_fbank as knf`.

AttributeError: '_kaldi_native_fbank.FbankOptions' object has no attribute 'dither'

Configuration options like 'dither' are nested within sub-objects (e.g., `frame_opts` or `mel_opts`) of the `FbankOptions` object and cannot be accessed directly.

fix

Access nested options through their respective sub-objects. For 'dither', use `opts.frame_opts.dither` instead of `opts.dither`.

TypeError: accept_waveform() takes 'torch.Tensor' but 'list' was given

The `OnlineFbank.accept_waveform` method expects audio input as a Python list or NumPy array, but a `torch.Tensor` was provided directly.

fix

Convert `torch.Tensor` input to a Python list or NumPy array before passing it to `accept_waveform`. For example, `your_audio_tensor.numpy().tolist()`.

Mismatch in fbank computation parameters causing deletion errors (e.g., high_freq)

The default or configured `FbankOptions` parameters, such as `high_freq`, may not align with the parameters used during the training of a specific model, leading to feature discrepancies and performance issues.

fix

Adjust the `FbankOptions` parameters (e.g., `opts.mel_opts.high_freq = -400`) to match those used in the training pipeline of the model you are integrating with.

Upgrade

Version history

1.22.3latest on PyPI · released Oct 9, 2025

Audit

Dependencies

torchoptionalUsed in common examples and for convenient waveform generation/handling, but not a hard dependency for the core library.

numpyoptionalOften used for array manipulation and is compatible with `accept_waveform` which takes list or numpy array.

Agent activity

7 hits · last 30 days

node

Resources

githubhttps://github.com/csukuangfj/kaldi-native-fbank ↗

packagehttps://pypi.org/project/kaldi-native-fbank/ ↗