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Neural codecs for wearable and physiological signals on edge devices.

compressionKIT helps teams compress continuous sensor waveforms before they become a memory, radio, battery, or cloud-ingestion problem. It is designed for wearable and edge signals such as PPG, ECG, IMU, and future time-series modalities where preserving waveform utility matters.

The package provides reusable codec blocks, deploy packaging, runtime loading, and validation scorecards. The v1 release artifacts focus on PPG and ECG, but the architecture is intentionally broader than any single method or modality.


What compressionKIT is

compressionKIT is a toolkit for building, evaluating, packaging, and deploying compression codecs for wearable signals.

It includes:

  • neural codec models and quantization components
  • DSP and hybrid codec stages where they are useful
  • preprocessing and augmentation blocks
  • physiological and signal-fidelity scorecards
  • deploy package generation with manifests, checksums, reference vectors, and C headers
  • runtime loaders for local and HuggingFace artifacts
  • golden release automation for supported PPG and ECG operating points

It is not a general physiological inference framework. It does not try to own arrhythmia classification, sleep staging, activity recognition, or downstream clinical decisions. It focuses on the codec layer: reducing data movement while preserving the signal content downstream systems need.

Current release scope

The current v1 release surface publishes neural codec bundles for PPG and ECG and includes reproducible DSP/hybrid comparison lanes. Those methods are examples of the codec framework, not the boundary of what compressionKIT can support.


Where compressionKIT fits

compression sits between the sensor and everything downstream: local storage, radio transport, gateway buffering, cloud ingestion, analytics, and model training. That position makes the codec a product boundary, not only a model choice. A release package needs to be small enough for edge deployment, explicit enough for validation, and stable enough that future codec versions can be compared against previously supported ones.

Modality Current status What preservation means
PPG v1 golden bundles and scorecards Pulse timing, HR/HRV agreement, morphology, motion/noise behavior
ECG v1 golden bundles and scorecards R-peak timing, QRS-band fidelity, morphology, artifact robustness
IMU Extension target Activity-band energy, event timing, orientation/motion features
Other wearables Block-level extension path Define the observables first, then choose codec and scorecard

What current goldens show

The first release-grade packages exercise the artifact contract on PPG and ECG, but the top-level question is not a single PRD curve. A customer needs to choose an operating point from compression level, physiology preservation, robustness, stitching behavior, and deploy footprint together.

Customer question Evidence surface Where to inspect it
What compression levels are available? Published CR ladder, frame duration, effective payload Customer evidence, Model zoo
How much signal utility survives? Truth PRD, PRDN-noise, HR/peak timing, band error, coherence PPG models, ECG models
What happens under noise or artifacts? Noise-tertile rows, SNR/artifact comparisons, and robustness scorecards PPG CR vs fidelity, ECG CR vs fidelity
Is stitching a problem? Seam ratio and long-recording stability checks Customer evidence, modality scorecards
Will it fit on my edge target? Encoder/decoder TFLite size, codebook size, deploy package contents Customer evidence, Deployment

The generated customer evidence summary is the compact entry point for this decision. Detailed plots now belong on the modality and CR-vs-fidelity pages, where they can be read with the matching sample counts, noise buckets, and reproduction links.


How to read the evidence

The headline numbers are a starting point, not the whole story. compressionKIT reports each supported codec through the same evidence surfaces so users can see what changed, what stayed comparable, and which signal conditions were tested.

  • CR vs. fidelity


    Report codec CR, effective CR when entropy models are present, waveform fidelity, physiological agreement, and stitching behavior in one table.

  • Noise and artifacts


    Split results by clean, median, noisy, empirical artifact, and SNR regimes; distinguish faithful PRD from clean-truth PRD and PRDN-noise so denoising behavior is visible.

  • Local imprinting


    Check that a codec does not hallucinate subject- or segment-specific detail, hide signal quality problems, or make noisy inputs look falsely clean.

  • Standardized comparisons


    Compare new candidates against every still-supported golden using the same datasets, sampling rules, scorecard schema, and artifact validation checks.

The guiding rule is simple: comparisons belong in generated scorecards, noise/artifact sweeps, and CR-vs-fidelity pages, not in one-off prose. When a new method or release arrives, the tables are regenerated from the supported artifacts so old and new versions remain comparable.


Guiding principles

These principles keep the toolkit practical without making every experiment use the same control flow.

Principle What it means in practice
Artifact-first Runtime loading, validation, docs, and publication are driven by deploy packages rather than training scripts.
Observable-preserving Each modality defines what must survive compression: timing, morphology, spectral content, or motion features.
Progressive disclosure Users can try a bundle in minutes, validate a deploy directory, then reproduce or extend only when needed.
Method-flexible RVQ, DSP, hybrid, entropy priors, and future codecs share the same release boundary.
Embedded-aware Blocks should be portable toward fixed-memory C/LiteRT deployment paths.

Why it matters

  • Wearable-first compression


    Reduce flash, PSRAM, BLE, cellular, and cloud-storage pressure by compressing the waveform at the sensor edge.

  • Signal utility preserved


    Scorecards report waveform fidelity and physiology-aware metrics such as PPG heart-rate preservation and ECG morphology behavior.

  • Deployable artifacts


    Export LiteRT/TFLite models, C headers, codebooks, reference vectors, and package manifests for edge and host runtimes.

  • Extensible codec surface


    Start from reusable blocks. Add new modalities, losses, quantizers, entropy models, or deployment targets without joining a mandatory experiment framework.


High-level getting started

Start with the lightest path that answers your question.

Goal Best starting point Dataset required?
Try a published codec HuggingFace guide or example notebooks No
Evaluate on your own signal Dataset setup ยท bring your own data Your signal only
Inspect supported release artifacts Model zoo and golden experiments No
Validate a deploy package Deployment guide No
Reproduce golden results Golden experiments Yes
Extend or create a new codec Experiment architecture Usually

Minimal runtime example:

import numpy as np
from compressionkit.runtime import load_codec

codec = load_codec("Ambiq/compressionkit-ppg-4x-v1.0")
frame = np.zeros(codec.frame_size, dtype=np.float32)

encoded = codec.compress(frame)
reconstructed = codec.decompress(encoded)

Install locally:

uv pip install "compressionkit[hf]"

# Or, from a source checkout:
uv sync --extra hf

Current v1 artifacts

The first release-grade packages exercise the common artifact contract across PPG and ECG:

Area Current v1 status Where to go
PPG neural codecs Published HuggingFace bundles from 2x to 32x PPG model zoo
ECG neural codecs Published HuggingFace bundles from 2x to 64x ECG model zoo
DSP and hybrid lanes Published HuggingFace bundles (SPIHT + hybrid, all CRs) Experiments
Release contract Manifests, specs, checksums, reference vectors, scorecards V1 release contract
Runtime/deployment Local and HuggingFace loading plus deploy validation Deployment guide

For method details, see Methods. For the philosophy behind blocks, ready-made experiments, and goldens, see Experiment Architecture.


Where to go next

  • Getting Started


    Install the package, run the notebooks, and learn the shortest path to a codec round-trip.

    Start here

  • HuggingFace Bundles


    Download a published codec, run it on a sample frame, and understand bundle contents.

    Load a bundle

  • Model Zoo


    Browse current PPG and ECG release artifacts, metrics, and package links.

    Browse models

  • Golden Experiments


    Reproduce, validate, stage, or extend release-grade experiments.

    View goldens

  • :material-blocks:{ .lg .middle } Experiment Architecture


    Learn how reusable blocks, recipes, deploy artifacts, and golden releases fit together.

    Read architecture

  • :material-badge-check:{ .lg .middle } Validation Scorecard


    Understand noise handling, artifact behavior, physiological metrics, and release checks.

    Read scorecard