nineninesix/emolia_filtered_nano_codec_21_dataset

Emolia · Filtered · NanoCodec (FSQ) Tokens

A cleaned, pre-tokenized version of laion/Emolia prepared for text-to-speech (TTS) training.

The pipeline is two steps:

1. Quality filtering with the open-source audio_filter tool — this removes the dirtiest recordings (noise, clipping, band-limiting, robotic artifacts, overlapping speakers), which matters a lot for TTS quality.
2. Discrete audio tokenization with NVIDIA nvidia/nemo-nano-codec-22khz-1.89kbps-21.5fps (an FSQ neural audio codec) — every waveform is replaced by 8 layers of integer codes.

The result is a compact, ready-to-train dataset: text + speaker + language + audio codec tokens. No raw audio is redistributed here — only discrete codec indices.

• Examples: 5,397,323 (single train split)
• On-disk size: ~68.9 GB (Apache Arrow, 138 shards)
• Audio codec: NanoCodec, 22 kHz, 1.89 kbps, 21.5 frames/sec, 8 FSQ codebooks
• Source dataset: laion/Emolia (CC-BY-4.0)

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Dataset structure

Each row is one utterance. There is no audio blob — the audio is encoded as 8 parallel streams of NanoCodec indices (nano_layer_1 … nano_layer_8), each of length encoded_len.

Column	Type	Description
id	string	Unique utterance id (carried over from Emolia)
text	string	Transcript of the utterance
speaker	string	Speaker id
language	string	Language code (en, zh, de, fr, ja, ko)
nano_layer_1	list<int64>	NanoCodec FSQ codes, codebook 1 — length encoded_len
nano_layer_2	list<int64>	NanoCodec FSQ codes, codebook 2
nano_layer_3	list<int64>	NanoCodec FSQ codes, codebook 3
nano_layer_4	list<int64>	NanoCodec FSQ codes, codebook 4
nano_layer_5	list<int64>	NanoCodec FSQ codes, codebook 5
nano_layer_6	list<int64>	NanoCodec FSQ codes, codebook 6
nano_layer_7	list<int64>	NanoCodec FSQ codes, codebook 7
nano_layer_8	list<int64>	NanoCodec FSQ codes, codebook 8
encoded_len	int64	Number of codec frames (≈ duration_seconds × 21.5)

The 8 nano_layer_* columns are aligned frame-by-frame: index t of every layer describes the same 1/21.5 s ≈ 46 ms audio frame.

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Usage

Load the dataset

from datasets import load_dataset

# Streaming is recommended — the dataset is large.
ds = load_dataset("nineninesix/emolia_filtered_nano_codec_21_dataset", split="train", streaming=True)

sample = next(iter(ds))
print(sample["text"], sample["language"], sample["speaker"])
print("frames:", sample["encoded_len"])
print("codebook 1:", sample["nano_layer_1"][:10])

Reconstruct audio from the tokens

The codes can be decoded back to a 22 kHz waveform with the matching NeMo NanoCodec model.

import torch
from nemo.collections.tts.models import AudioCodecModel

codec = AudioCodecModel.from_pretrained("nvidia/nemo-nano-codec-22khz-1.89kbps-21.5fps")
codec.eval()

# Stack the 8 layers into (Batch=1, Codebooks=8, Time)
layers = [sample[f"nano_layer_{i}"] for i in range(1, 9)]
tokens = torch.tensor(layers, dtype=torch.long).unsqueeze(0)          # (1, 8, T)
tokens_len = torch.tensor([sample["encoded_len"]], dtype=torch.long)  # (1,)

with torch.no_grad():
    audio, audio_len = codec.decode(tokens=tokens, tokens_len=tokens_len)

# audio -> 22 kHz waveform, save with soundfile/torchaudio

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How this dataset was built

1. Quality filtering — audio_filter

We ran every Emolia recording through the open-source audio_filter pipeline and kept only the clean ("good") audio. The tool analyzes acoustic / spectral characteristics and assigns each file a verdict of good, uncertain, or bad in two sequential stages:

• Acoustic quality screening — rejects noisy, clipped, robotic, or bandwidth-limited recordings using spectral degradation metrics. Two models are used depending on the audio bandwidth:
  • V1 for narrowband audio (≤ 24 kHz), scoring 12 acoustic metrics;
  • V2 for wideband audio (> 24 kHz), scoring 34 acoustic metrics with loudness normalization.
• Speaker-overlap detection — a Pyannote segmentation model flags files that contain simultaneous speech from multiple speakers; this runs only on files that already passed the quality stage.

Only recordings that passed both stages ("good") were retained for tokenization. This step is what removes the "dirtiest" audio and is critical for downstream TTS quality.

Reproduce the filtering with the exact tool and thresholds documented in the repo: https://github.com/KaniTTS-research-team/audio_filter

2. Tokenization — NVIDIA NanoCodec (FSQ)

The surviving clean audio was encoded with nvidia/nemo-nano-codec-22khz-1.89kbps-21.5fps, a Finite Scalar Quantization (FSQ) neural audio codec:

• Sample rate: 22 kHz
• Bitrate: 1.89 kbps
• Frame rate: 21.5 frames/second
• Codebooks: 8 (stored as nano_layer_1 … nano_layer_8)

Each waveform becomes 8 aligned integer streams plus encoded_len (the number of frames). Raw audio is not included — only these discrete indices, which keeps the dataset compact and avoids redistributing the source audio.

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Provenance & derivation

This dataset is a derivative of laion/Emolia, an emotion-enriched multilingual speech dataset built on top of Emilia (and its YODAS subset). We did not change the transcripts, speaker ids, or language labels — we only:

1. Filtered out low-quality / overlapping-speaker recordings, and
2. Replaced the audio waveforms with NanoCodec (FSQ) discrete tokens.

For details about the original annotations, emotion labels, and speaker embeddings, see the Emolia dataset card.

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Licensing & attribution

• This packaging (README, filtering/tokenization pipeline, and the code representation of the data) is released under the Apache License 2.0.
• The underlying speech content is derived from laion/Emolia, which is distributed under CC-BY-4.0. Attribution to LAION / the Emolia and Emilia authors is required, and you must comply with CC-BY-4.0 (and the original Emilia terms) when using the audio-derived content in this dataset.

By using this dataset you agree to respect both the Apache-2.0 terms of this repository and the CC-BY-4.0 terms of the upstream Emolia data.

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Citation

If you use this dataset, please cite the upstream Emolia / Emilia work and this repository.

@misc{emolia_filtered_nanocodec,
  title        = {Emolia · Filtered · NanoCodec (FSQ) Tokens},
  author       = {Nineninesix, Inc.},
  year         = {2026},
  howpublished = {\url{https://huggingface.co/datasets/nineninesix/emolia_filtered_nano_codec_21_dataset}},
  note         = {Filtered and NanoCodec-tokenized derivative of laion/Emolia}
}

Please also cite the source dataset laion/Emolia and the NVIDIA NanoCodec model.

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Acknowledgements

• LAION and the Emolia / Emilia authors for the source dataset.
• NVIDIA NeMo for the NanoCodec (FSQ) audio codec.
• audio_filter for the quality-filtering pipeline.