HEEP Universal

High Entropy Exponential Pruning for State-of-the-Art Multilingual ASR

HEEP Universal is a state-of-the-art automatic speech recognition model that demonstrates how strategic entropy-based data curation outperforms brute-force data scaling. With a composite word error rate (WER) of 3.10% on English benchmarks, it challenges the "more data is better" paradigm by training on carefully selected high-information samples.

Model Overview

HEEP Universal supports transcription across 204 languages, including a wide range of Indic and global languages, with consistent performance across various domains such as meetings, earnings calls, broadcast media, and educational content. The model is optimized for high-precision, verbatim transcription capturing spoken content word-for-word with remarkable fidelity.

Core Insight: Strategic selection of high-entropy samples leads to better ASR models than training on larger but redundant datasets.

HEEP Methodology

HEEP (High Entropy Exponential Pruning) is an entropy-based data curation methodology that prioritizes information density over data quantity. It identifies high-information training samples while progressively filtering redundant data, enabling efficient model training with significantly reduced computational resources.

Mathematical Foundation

Sample Score (Equation 1)

The information score for each sample combines multiple entropy dimensions:

S(x) = α₁·H_acoustic(x) + α₂·H_phonetic(x) + α₃·H_linguistic(x) + α₄·H_contextual(x) + β·MI(x, D)

Where:

H_acoustic(x): Spectral/MFCC entropy measuring acoustic diversity
H_phonetic(x): Phoneme distribution entropy capturing phonetic complexity
H_linguistic(x): Vocabulary and syntax entropy measuring linguistic richness
H_contextual(x): Domain and discourse entropy
MI(x, D): Mutual information contribution relative to dataset
α₁...α₄, β: Configurable weights (default: 0.25, 0.20, 0.25, 0.15, 0.15)

Mutual Information (Equation 2)

The mutual information between acoustic features and transcription:

I(x, y) = Σ_{j,ℓ} p(f_j, y_ℓ) log [p(f_j, y_ℓ) / (p(f_j)·p(y_ℓ))]

Selection Criterion

Samples are selected based on a threshold:

D' = {x ∈ D : S(x) > τ}

Progressive Filtering (Equation 8)

The threshold increases exponentially across rounds:

τ_{k+1} = τ_k · growth_factor

Error-Aware Adaptation

After each training round, sample scores are adjusted based on model errors:

S'(x) = S(x) + λ_err·ErrorRelevance(x, errors_k) + λ_cross·CrossLingualOverlap(x)

Algorithm Overview

Algorithm: HEEP Data Curation with Error-Aware Adaptation

Input: Dataset D, initial threshold τ₀, growth factor g
Output: Curated dataset D*

1. Initialize scorer with entropy estimators
2. Fit scorer to D (compute normalization stats, fit MI estimator)
3. D* ← D
4. k ← 0
5. While |D*| > min_samples AND k < max_rounds:
    a. For each x in D*:
        Compute S(x) = Σᵢ αᵢ·Hᵢ(x) + β·MI(x, D)
    b. If error_patterns available:
        Adjust S'(x) = S(x) + λ_err·ErrorRelevance(x) + λ_cross·CrossLingualOverlap(x)
    c. D* ← {x ∈ D* : S'(x) > τₖ}
    d. If train_callback: Train model on D*
    e. If eval_callback: Analyze errors, update error_patterns
    f. τₖ₊₁ ← τₖ · g
    g. k ← k + 1
6. Return D*

Key Benefits

Training on 10-20% of data while matching or exceeding full-dataset performance
Efficient multilingual model development with cross-lingual transfer
Error-aware adaptive sample selection across training rounds
Significant reduction in computational resources and training time

Performance Benchmarks

OpenASR Leaderboard Results

Dataset	WER (%)	RTFx
AMI Test	4.19	70.22
Earnings22 Test	5.83	101.52
GigaSpeech Test	4.99	131.09
LibriSpeech Test Clean	0.71	158.74
LibriSpeech Test Other	2.17	142.40
SPGISpeech Test	1.10	170.85
TedLium Test	1.43	153.34
VoxPopuli Test	4.34	179.28

Composite Results

Overall WER: 3.10%
Average RTFx: 146.23

RTFx (Real-Time Factor) indicates inference speed relative to audio duration. Higher values mean faster processing.

Model Details

Architecture: Transformer-based encoder-decoder optimized for multilingual transcription
Languages: 204 languages supported
Format: Transformers compatible (safetensors)
Sampling Rate: 16 kHz
Precision: FP16/FP32 supported
Optimization: Real-time inference capable with GPU acceleration

Key Features

Exceptional Accuracy: Achieves 3.10% WER across diverse English test sets
Real-Time Performance: Average RTFx of 146.23 enables real-time applications
Verbatim Transcription: Optimized for accurate, word-for-word transcription
Multi-Domain Excellence: Superior performance across conversational, broadcast, and read speech
Multilingual Support: 204 languages with cross-lingual transfer learning
HEEP-Curated Training: Strategic entropy-based data selection for maximum information density

Usage

from transformers import AutoModelForSpeechSeq2Seq, AutoProcessor, pipeline
import torch

device = "cuda:0" if torch.cuda.is_available() else "cpu"
torch_dtype = torch.float16 if torch.cuda.is_available() else torch.float32

model = AutoModelForSpeechSeq2Seq.from_pretrained(
    "bc7ec356/heep-universal",
    torch_dtype=torch_dtype,
    use_safetensors=True,
)
model.to(device)

processor = AutoProcessor.from_pretrained("bc7ec356/heep-universal")

pipe = pipeline(
    "automatic-speech-recognition",
    model=model,
    tokenizer=processor.tokenizer,
    feature_extractor=processor.feature_extractor,
    torch_dtype=torch_dtype,
    device=device,
)

result = pipe("audio.wav")
print(result["text"])

Use Cases

HEEP Universal excels in various speech recognition scenarios:

Meeting Transcription: High accuracy on conversational speech (AMI: 4.19% WER)
Financial Communications: Specialized performance on earnings calls (Earnings22: 5.83% WER)
Broadcast Media: Excellent results on news, podcasts, and media content
Educational Content: Optimized for lectures and presentations
Customer Support: Accurate transcription of support calls
Legal Documentation: Professional-grade accuracy for legal proceedings
Medical Transcription: High-quality transcription for medical consultations

Performance Optimization Tips

GPU Acceleration: Use device="cuda" for significantly faster inference
Precision: Set torch_dtype=torch.float16 for optimal speed on modern GPUs
Language Specification: Specify language code when known to improve accuracy and speed
Beam Size: Use beam_size=5 for best accuracy, reduce for faster inference
Batch Processing: Process multiple files with a single model instance for efficiency

Acknowledgments

HEEP Universal was developed using the HEEP framework for entropy-based data curation. We thank the open-source community for providing foundational tools that make this work possible.

Citation

If you use this model in your research, please cite:

@article{anonymous2026heep,
  title={HEEP: High Entropy Exponential Pruning for State-of-the-Art ASR Through Strategic Data Curation},
  author={Anonymous},
  journal={Under Review},
  year={2026}
}

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Safetensors

Model size

0.8B params

Tensor type

F32